The FACTORY MANUALS are the best. For almost all repairs, they give thorough instructions. They are written by the enginers that designed the car! Haynes, Chilton, Mitchell... are ok. One good thing about the non-factory manuals/data: they show alternative ways of solving problems...without the ultra expensive factory tools, jigs, etc.
Glad to see progress! These old rear wheel drive Volvos will run forever with just basic maintenance. I just purchased a 1989 240 sedan for $225 US that was severely neglected and for just a few hours of my time it is back to life. Save the Volvos worldwide!
Congratulations! Very durable car (got one 1990 to) A nice fuelsaving mod is to get rid of the original viskosfan and add a aftermarket electric fan with a termoswitch. Did it to mine and it works great👍
If the fuel pump won't shut down after few seconds while the engine is off, your fuel system has a leak somewhere preventing the pressure build up, or the fuel pump is weak and needs to be replaced. Also the time that the fuel pump stays on after the switch is off, is due to the relay residual inductance.
Really love your videos! I am always waiting anxiously for a new episode to come out :) Glad that you are making more car repair videos. Keep up the great work!
The fuel pump on these, and indeed all fuel injected cars, isn't controlled by an electronic timer but rather by a pressure switch mounted on the end of the fuel rail on the engine that feeds the fuel injectors. What should happen is that when you switch the ignition on before starting the car (so that the warning lights on the dashboard come on) the fuel pump will run until the fuel pressure in the fuel line and fuel rail reaches a certain point which is above what the car requires to start. This won't be the same for every car due to variation in maintenance and manufacturing tolerances in the components in the fuel system so having some form of electronic timer won't work. Just like oil pressure warning light switches in car engines the fuel pressure switch suffers from mechanical wear so that eventually the switch may turn off the fuel pump before there is enough fuel pressure for the car to start which can lead to lazy owners by-passing the fuel pressure switch and so the fuel pump runs all the time that the ignition is switched on as here. What can also happen, more unusually, is that the switch fails in a way that it is constantly active as here, possibly due to internal corrosion or contamination of the switch. Being as the fuel pump relay, a common failure point on these cars and indeed most fuel injected Volvos, appears to be in good condition and working correctly I would suggest that replacing the fuel pressure switch is extremely likely to solve the problem, especially if the switch is visibly old as it may well be the original part and all they are, basically, is a spring-loaded contact which makes or breaks the circuit and over time the spring is going to wear out. It is worth making the point that when working on the fuel system of a fuel injected vehicle it is essential to depressurize the fuel system as it runs at much higher pressure than on a carburettor vehicle. The usual and best method to do this is to remove the fuel pump fuse and then start the car and allow it to run until it stalls, then attempt to start it 4 or 5 more times which uses up the fuel in the fuel lines and enables the fuel system to be opened with just a small loss of fuel rather than the large spray of high pressure fuel that you otherwise get and which is highly flammable, as I have experienced in the past...
I just love this video! You are so systematic, it´s fun to watch. Good filming too!! You don´t have all the answers from the beginning, you reason yourself forward. Really clever! This is DIY super stuff! I really liked your reasoning with the rapidly blinking turning lights. Do we get to see the car on the road, ready, running and shining? Please post a fourth video. I have fallen in love with your Volvo! Ove, Sweden
My dad had the sedan version of this car until he developed epilepsy, I miss it as we had great memories driving it. It had the same colour like this car.
The flasher is a old fashioned bi-metalic strip circuit breaker (a electromechanical multivibrator). The turn signal circuit cycles by a function of the amount of current that flows through the bi-metalic strip. A overloaded or shorted turn signal circuit to ground will cause the lights to flash rapidly. Some thought should go into rewiring the trailer lights and possible auxiliary power...those little wires can only supply a small amount of current.... In USA the Department of Transportation dictates (since a lot of light duty trailers have "electric brakes": things get complicated for "failsafe" operation). Approved designs are available.
We got a load of manuals and guides for Volvo 740 and 940 and more on the channel and the website if you need. That haynes manual are a bit hard to understand and there is some really bad pictures in that book.
Ah, I miss my Volvo brick. If you do replace the in tank pump, upgrade it to a 740 turbo's pump. They flow a lot more and help reduce the strain on the main fuel pump. :)
These cars are amazing! I used to have one, and now I drive a 240. My 240 drove for several years with a loose carburettor.. the carburettor was just sitting on top of the engine with loose bolts ;).. I also made a video about diagnosing that weird problem, which ppl might find useful..
Absolutely positive. The pump should shut off after a few seconds if the ECU looses cranck signal (key in II pos). I'm an authorized car technician so i'm pretty sure on this. The relay should have a control signal from the ECU directly or via other control circuits. I suspect that someone has damaged the original wiring system when doing a repair job and not being able to correct the problem they probably added wires to the system to make the pump run uncontrolled from ignition switch (key pos II). It makes no sense that fuel pump runs for a few seconds in AUX ( I ) position. This is how the fuel system should work when key is in pos II and the pump should not run at all in pos 1 (AUX) I hope you love reading wiring diagrams cause this seems to be a complex problem. I would suggest that you first follow the circuitry activating the coil in the fuel pump relay all the way to the ignition switch. I bet you will find a fuel shut of control relay somewhere in between. Pay especially notice to the wiring and the color coding on these components. Good luck!
Big thumbs up here. Definitely check that the wiring is correct. The fuel pump should not run until in Pos 2, and then just for no more than 2 seconds or so. I completely agree that someone has likely found an issue and applied a "work around" by adding a wire to make it run all the time. I might even consider that the fuel pressure sensor (if equipped in this car) went bad and this was how they fixed it.
Be nice to get a fuel pressure gauge on the fuel rail, then compare to specs. However, it appears the fuel filter was the urgent problem. I always wanted a 740 wagon. I had a 142, a 164, a 244 wagon, and an 1800S. Check that timing belt.
I think that the fuel pump may have an internal pressure switch that shuts off the pump when the line to the fuel distribution system is sufficiently pressurized. You should be able to verify that with the new pump on the bench. FYI: On many GM large SUVs or pickups vehicles there is an electric fuel pump near the left rear wheel that is fairly loud and does seem to run continuously. As most flasher units use bi-metallic strips as the timing element, the current load of lamps determines the flashing rate. When a lamp burns out you will notice that the flashing rate slows down. The relays allow the flasher to see the normal complement of lamps while providing a separate circuit for the trailer tail, brake and turn signals. I think that i heard a sound related to a mis-adjusted or worn belt running off of the crankshaft pulley. The video showed the alternator or power steering pump belt with too much play while running. It is becoming popular to substitute a computer tablet for the source signals for the sound system. The tablet usually has a navigation app that uses the device GPS system to function. Also any stored music can be played through the former CD or cassette inputs. The Bluetooth capability may make a legal hands-free telephone connection and/or play tunes from your smartphone. I noticed that you mentioned that you lost your job from your previous employer; I hope that you found something better in Koln. (I used to have a 1974 Mercury Capri (Ford) that was assembled in Koln (my most reliable car until I let the Los Angeles California air embrittle a short section of rubber fuel hose that began burning while driving on a freeway (bahn) with my infant son in a rear car-seat. I got him out but could do nothing to extinguish the flames while holding my son (lost the car-seat too). I have yet to watch episode three of the Volvo project. good luck. I'm not a mechanic, but a retired videotape & systems technician (they call us engr.s but I am self taught; no degree).
the noise from a pump like that can be caused by cavitation. It could be that there is a pinhole in the suction side fuel line. These often don't leak owing to vacuum pressure but do admit air. Further - the pump may not be timed but is switched via a pressure transducer at the intake manifold or carburetor (if old school). Owing to air being compressible the pressure may be insufficient to trigger the transducer causing continuous running. I only mention this to prevent you from swapping working parts and not fixing it! BTW - I'm not a mechanic but a process pipework engineer...
I agree however I have seen some cars that have a pumps that do constantly run and whatever fuel is built up pressure wise recalculates back to the tank. I've only seen this happen to older Dodges and I don't know much of anything of Volvo.
I've also seen it caused by the tank lift pump as mentioned in the vid. Suction from the main pump lowers the pressure in the line from the tank causing the fuel to pretty much boil, hence the cavitation noises.
Hmmm, might be worth checking. I had an F reg ford granada that had a colision detector module next to the boot latch that triped when every time a heavy tool bumped about in the boot, i wonder if it may have been bypassed in the same peculiar way as the indicators where, as towing would have definatly triped my granada on every bump. However go with the experianced, the tank pump not delivering enough volume of fuel to the fuel injection pump does make sence.
I would also take a quick look at the fuel pressure regulator (FPR). There are 2 lines, 1 goes to the FPR from the tank, and 1 goes back to the tank (the return line). Unplug the return line from the tank and put it into a canister of some sort (or unplug it from the FPR and run a spare line into the canister). Start your car, there should be a large amount of gas coming out of this return line. If there is not, your FPR is bad and must be replaced. A fuel pump is capable of delivering MUCH more gas than is needed, the FPR sends the excess back to the tank, this could be damaged and not allowing the excess back to the tank. It's essentially free to check and not overly difficult.
As mentioned in another post the sound from the fuel pump could have been cavitation, it sounded like that and maybe you were getting some air in through the old filter. I am looking forward to seeing all the repairs you end up making on this vehicle. It looks like the car is not bad from a rusting/rotting problem.
I think it might be worth seeing about buying some fuel hose and re-doing all the fuel lines when you do the pumps. They really don't look very good. If you don't have a tiny fuel leak or air getting into the system I think you will. Also when you take the tank pump out it might be worth flushing out the fuel tank because after 20 years the tank probably has some crud in it. I think for a modest amount of money and a bit of time you could turn that Volvo into a good reliable car. I think it was a pretty good find. A lot of these have since gone to the scrap in the UK because their owners wanted something newer or couldn't afford to fuel them.
The relay turns on and off to adjust for fuel line pressure so excess pressure won’t fold engine or overwhelm fuel return system. Part of what makes it meet California emissions.
I'm not 100% sure on Volvo's, but on most EFI cars, the engine control module energizes the fuel pump relay, and thus the control logic is in the ECM, not an external circuit. Many will do a pump prime at key on then shut off, and wait for an ignition or crankshaft position sensor indication that the vehicle has started. At this point the fuel pump will be energized continuously until the engine is shut off or stalls. The mosfets that control this relay in the ECM do on occasion fail, and some mechanics will simply wire the fuel pump relay directly to a key on power source rather than repair or replace the ECM. In this case, the fuel pump will run continuously whenever the key is on, rather than prime and run only when the engine starts. The risk is in an accident the fuel system will remain pressurized and pump fuel whereas factory configuration will shut off fuel if engine is stopped. Also if you have a leaky injector, the cylinders or upper intake can flood in a key on, engine off state. Just my 2 cents, but verify that fuel pump relay exciter wire runs to ECM, and verify ECM is putting out 12v as intended.
Once I had suspect a problem with the white relay. I guessed that the coil inside is getting weak, so I adjust the related parts in the relay to compensate for it. Unfortunately I forgot what exactly since it was long ago. It works anyway. So much custom relay this car have.
The fuel pumps are controlled by the Engine Computer, the ECM, through the Fuel Pump Relay. Pretty sure the fuel pump isn't suppose to run all the time. Normally they run for about 5 seconds and if there is no crankshaft sensor input indicating cranking/running, then the ECM shuts the pump off when the Fuel Pressure Sensor or Switch says that the system is pressurized. They did this to keep the fuel pump from running all the time and to ensure that there is good line pressure to reduce crank times. Anyway, change the in-tank filter at the VERY least, preferably the whole pump too given it's age and the low cost of a replacement pump. Most likely the in-tank filter is clogged and reducing pressure to the second pump causing cavitation when the fuel boils in the partial vacuum. You can hear it when the pump runs, that's what the Whhiirr - Grrrrr- Whhirr noise is. The Grrrs are the cavitation. This is one of the biggest problems with two pump systems.
For the inspection in Germany you need to have a cover over the positive connection of the battery, as far as I remember (something to add to the list ^^)
keep the new fuel pump, but make a small adaptor loom so you dont have to change the old wiring; best of both worlds!, the fuel pump would be timed by pressure not electronics, so would be a valve/solenoid inside the pump, again, try the new pump and see if the situation changes.
The fuel pump fault may be caused by a faulty air flow sensor. If it's Bosch L Jetronic or a similar moving vane type there is a switch under the cover that detects air movement and switches the pump via the relay and ECU.
Oh yeah, don't touch the in-tank pump unless you have to. I guarantee that each of those fuel and return lines are going to need repair or replacement if you disconnect them, and the lines on some cars can be very long and hard to get to.
I have a 1990 Volvo 760 GLE with the V6 engine. The car has about 240,000 miles with the original fuel filter. Your fuel filter and fuel pump is configured just like mine. Your video is helpful in showing that these parts can be removed as a unit, then placed on a bench for further disassembly. However your video did not show how you disconnected the power cable wire to the fuel pump?
Hi mate, It looks like you have found yourself a very nice example of a Volvo, given that cars in Europe have a lot to deal with like salt, acid rain, and mechanics that don't care about your car . I have always liked the Volvos, but for their being quite underpowered for the bulk of the vehicle, power to weight ratio. I think I would like to see them with a nice V8 in them. I think that you will have to find some good replacements for all the plastics, if it has not broken now it will break soon, or when you take it loose. Unfortunately, a lot of mechanics are not very good at looking after the plastic panel parts of the car.
Great job fixing the lights and filter :-D People modify things without thinking, best to rip out the non standard systems :-). I would have made patch cables for the new pump from ebay, converter cables :-).
I agree with this. My view on repairs and restorations is that "factory standard" is not necessarily the best standard, it was the most cost efficient production standard.
the fuel pump doesn't turn off via a timer. Most "modern" vehicles the pump turns off once it reach's a certain fuel pressure. I don't know about your car in particular, but it may or may not be designed that way. The other way it's done is for the pump to run 100% of the time, and a fuel pressure regulator returns excess fuel to the tank via a return line. If your not able to get a refund on the pump you already bought, and are unwilling to change the connector on the car itself you might consider making a adapter. You might even be able to use the connector from the old pump, along with a few bits of wire and new connectors for the new pump.
the fuel pump turning off is probably linked to fuel rail pressure. the filthy filter was probably preventing the rail getting to pressure. that old filter was probably putting too much strain on the filter or cavitating.
Turning the ignition back should only turn on accessories radio and so on. Forward one time should turn the fuel pump on for a very short period of time less than 30 seconds. Turning it Forward twice from the off position the fuel pump will run constantly you will also get check engine light because normally Click 2 is where the car would normally be at when running after starting the engine. A consistent amount of fuel is sent to the engine any fuel that is not used will be sent back to the gas tank. That is why you see two gas lines.
The fuel pump shouldn't keep running with the ignition in run. Whatever drives that relay should have an RPM input as well as an ignition switch input, and shut the pump off if the engine stops running. This helps prevent a fuel fed fire in a crash.
Right, it should run for a moment and then shut off. When the system which runs the fuel pump relay senses the engine turning it turns the fuel pump back on.
PS. What I definitely want to do is to replace the fuel filter. Can you share how you disconnected the fuel hose from each end of the filter and reconnected. Are there any special tools or parts needed? Thanks.
though i'm glad you fixed things to your liking i do enjoy the idea of the spastic blinkers. Volvos are such sedate cars, it's like yours had too much caffeine.
No more hesitation on wide open throttle?? Asking as i own an 88 that's fuel pump sounds like that and its cutting out when on wide open throttle at low speed only so im thinking it would be the fuel filter blocking enough fuel from going to the rail! Pls respond i know its an old video but there isnt much content revolving around diying 740's H
Hi dreamsun. My 740 has only one intank fuel pump as it is a Regina system. I don't know if yours is. For quite sometime I have been having a hesitation ( backfire too) when the throttle is wide open . I will be fixng this soon ( after a lot of parts swap). It seems to me after extensive research on the internet , that the pulasation damper may be leaking. This is the ( some folks call it a pillow, others say it looks like a mini old ford brake master cylinder cover) little thingy that is attached to the output of the fuel pump. Many owners have had succes just removing this and installing a SUBMERSIBLE fuel line in place. I will be fixing this soon as it is not a priority now. Hope this helps
Nice, i hawe two old volvo, unfortunatly older model then this so i don´t know much of the 740 series, but there are lot of cheap spareparts around here in the origin country of Volvo... I think i possibly hawe some old intake parts, that i once found on a scrap Yard, for the 740 somewhere... Scrap cars are wery common here since we (in Sweden) does not hawe that law that provide people from letting old cars rust on tha backyard so many people (like me for example...) saving old cars for spare parts, one can ofte pick one up sheep i one need bigger or more expensive parts and then send the rest of it to metal recycling or sellin the remaining part weither. Unfortunatly i am more or less constantly out of money so i cant send anything at the moment, but i can give You the intake bar for free if You want it and possibly some other person can pay the shipment.
That car sure hasn't seen maintenance in many years!! Fuel filters must one of the most neglected service parts, most likely because of the location and relative difficulty in replacing them. Also garages charges for such items are excessive. I wouldn't like to live in Germany from a car owning perspective, the TUV is very severe! The UK actually imports part worn tyres from Germany because when they fail there they are still legal in the UK!!
Hi, my Volvo 740GL petrolengine( year 1986) will not shut OFF on many occasions. It will switch off if i turn key ON and immediately turn the key off. Sometimes i must repeat this action several times!! Any suggestions would be greatly appreciated as i have not found a solution yet, even after having it serviced at Volvo Distributor in my country
I always thought that the fuel pump shuts off automatically due to a pressure switch, so it builds up fuel pressure and then, when the necessary pressure is reached to start the engine, it will shut off. If that is the case, then there is no timing circuit needed for that, but some fuel pressure sensor on the engine. In that case, "it shuts off after a few seconds" would have been to describe "it shuts off when the correct fuel pressure is reached". But then, I didn't even look at the engine when it was shown in the video, in order to see whether it is carburated or fuel injected. I am guessing the latter, which would mean that it is electronically controlled by some kind of ECU. Look in the service manuals if you can see a fuel pressure sensor somewhere on the fuel rail or whatever type of fuel injection it may use, and see if that maybe needs replacing? Disclaimer: I'm just guessing here though, I've only got theoretical knowledge, never done any serious work on a car. It may be I'm right, or it may be I'm totally off and it's a completely different issue, or possibly even none at all.
you are correct it builds pressure and stops, i believe that mechanism is in the pump, and the pump is worn so leaking pressure back from its valves and not shutting off, he should use the new pump seeing as he bought it, i see no issue on a small wiring mod to use it, i doubt it will ever need replacing again to worry about.
The pressure switch can be on the fuel rail, in the line, in the pump, or in the tank. Depends on where they put want to put it. Today on most systems the ECM will time out the pump if they don't get a crank signal after about 5 seconds regardless of the fuel pressure to keep from running the pump if there is a leak in the line somewhere.
jusb1066 Alright, but the problem with the wire mod is that this is Germany. He briefly mentioned the vehicle safety inspection (just as "inspection"), and any part that isn't stock has to have a dedicated permit of operation (usually, spare parts or modifications come with it or are not legal to be used), which you won't get for a wire mod, so it could mean the car is never allowed on the road again, because he cut off the plug from the wiring harness to the old fuel pump.
Seegal Galguntijak then i dont get how it was allowed to have all that wiring badly modified for the turn signals and terrible radio fitting job, but two new terminals on a fuel pump is not allowed....we have a EU vehicle safety inspection in the UK, but well made terminals on a new fuel pump would not be an issue
jusb1066 It was a presumption that he could get problems with that. I think it would stronly depend on how well the wiring is done, how well it's protected from the environment and so on. But the turn signals probably weren't legal either, how it was on the road like that remains a mystery to me. But, as always if you know the inspector, he can overlook certain things... The radio is not relevant for the safety and operation of the vehicle, so there you can get away with almost anything...
i do not understand why he installed the relays there.. i have the same model of the car, and my trailer wires are tapped into the rear light wires and the blinkers work just normal that way, without any addition relays.. strange
I think the previous owner cut the turn signal wire, wired the relay in series straight to a ground, then wired both the turn signals and the trailer lights to the load side of the relay. That caused less resistance in the turn signal circuit and the flasher relay to work faster. They should have just spliced the relay into the turn signal wire and left the bulb alone.
And even if they do, you'll need a special computer to program all the different computers for different purposes. These things (the ones that can do almost anything) are really expensive, like in the 3 to 4 figure range. And if the car is from any brand of the Volkswagen group, the universal computers don't even help, because they've got their own special system in the 5-figure-range. At least that's what a buddy of mine who works in a repair shop told me.
If I recall correctly the fuel system has the pump, the filter and an accumulator. When going to position 2 on the ignition switch the pump kicks in and if healthy charge the accumulator and when system pressure is achieved I believe a pressure sensor cuts the pump off. Of course if you start the engine then the fuel flow will drop the pressure and the pump will kick in immediately and the accumulator then essentially acts as a pressure damper. Long time since I had a Volvo so forgive me - and I am get ting old as well.😀👍
Wow, that is some rusty POS... I have big respect for people who get stuff like that working again or even in a perfect condition... I am far too lazy for that kind of stiuff... I just installed a new headunit into my car and had to find a switched 12V contact for that and run a wire. 1h worth of work for me and i hated it...
Most cars are completely gone when they even reach 20-25 years. I repaired many cars and volvo is on top of my list of durable and easy to service cars. Have seen old and new ones with over half million km with very few worn out parts. The old 700 series is also a nice car to drive, especially with some small mods to improve road holding.
zoidberg444 Yep, i think it is actually a very good time to buy a car currently, old cars are cheap and still in reasonable condition for the most part. Also they are realtively easy to work on and super high quality compared to modern cars. Still i had to buy a relatively new car because i hate working on them...
your fuel pump should shut off. you should only hear it for a few seconds after you turn the key (thereby priming the pump). the only situation in which I've seen a fuel injected vehicle with a continuously running fuel pump is in racing cars with a modified fuelling system. my guess is that the PO rigged up some kind of jumper to switched power in order to keep the pump on. no clue as to why someone would do that though. my 1989 325I has a dual pump setup like yours, and I would love to see how bad the inside of that filter looks. I changed mine 30 k after buying it, and threw it away without thinking about it.
One thing I like about VW/Audi is that you can download all the service/repair information for a nominal fee (I think 10eur or something), including schematics. This Volvo would just be a little too old and too rusty for me.
30 years ago I worked on the assemblyline at VOLVO. This brings back memories, thanks for that...
The FACTORY MANUALS are the best. For almost all repairs, they give thorough instructions. They are written by the enginers that designed the car! Haynes, Chilton, Mitchell... are ok. One good thing about the non-factory manuals/data: they show alternative ways of solving problems...without the ultra expensive factory tools, jigs, etc.
Glad to see progress! These old rear wheel drive Volvos will run forever with just basic maintenance. I just purchased a 1989 240 sedan for $225 US that was severely neglected and for just a few hours of my time it is back to life. Save the Volvos worldwide!
I come from a Software engineering background, but you've given me interest in both EE and general mechanical maintenance, cheers!
A $400 multimeter being used on a $500 car lol... A man's gotta have priorities
It's called Deutsche Gründlichkeit.
Congratulations! Very durable car (got one 1990 to) A nice fuelsaving mod is to get rid of the original viskosfan and add a aftermarket electric fan with a termoswitch. Did it to mine and it works great👍
add a thermo switch from a 940...IF you can find 1
If the fuel pump won't shut down after few seconds while the engine is off, your fuel system has a leak somewhere preventing the pressure build up, or the fuel pump is weak and needs to be replaced.
Also the time that the fuel pump stays on after the switch is off, is due to the relay residual inductance.
Really love your videos! I am always waiting anxiously for a new episode to come out :) Glad that you are making more car repair videos. Keep up the great work!
The fuel pump on these, and indeed all fuel injected cars, isn't controlled by an electronic timer but rather by a pressure switch mounted on the end of the fuel rail on the engine that feeds the fuel injectors. What should happen is that when you switch the ignition on before starting the car (so that the warning lights on the dashboard come on) the fuel pump will run until the fuel pressure in the fuel line and fuel rail reaches a certain point which is above what the car requires to start. This won't be the same for every car due to variation in maintenance and manufacturing tolerances in the components in the fuel system so having some form of electronic timer won't work. Just like oil pressure warning light switches in car engines the fuel pressure switch suffers from mechanical wear so that eventually the switch may turn off the fuel pump before there is enough fuel pressure for the car to start which can lead to lazy owners by-passing the fuel pressure switch and so the fuel pump runs all the time that the ignition is switched on as here. What can also happen, more unusually, is that the switch fails in a way that it is constantly active as here, possibly due to internal corrosion or contamination of the switch. Being as the fuel pump relay, a common failure point on these cars and indeed most fuel injected Volvos, appears to be in good condition and working correctly I would suggest that replacing the fuel pressure switch is extremely likely to solve the problem, especially if the switch is visibly old as it may well be the original part and all they are, basically, is a spring-loaded contact which makes or breaks the circuit and over time the spring is going to wear out. It is worth making the point that when working on the fuel system of a fuel injected vehicle it is essential to depressurize the fuel system as it runs at much higher pressure than on a carburettor vehicle. The usual and best method to do this is to remove the fuel pump fuse and then start the car and allow it to run until it stalls, then attempt to start it 4 or 5 more times which uses up the fuel in the fuel lines and enables the fuel system to be opened with just a small loss of fuel rather than the large spray of high pressure fuel that you otherwise get and which is highly flammable, as I have experienced in the past...
I just love this video! You are so systematic, it´s fun to watch. Good filming too!! You don´t have all the answers from the beginning, you reason yourself forward. Really clever! This is DIY super stuff! I really liked your reasoning with the rapidly blinking turning lights. Do we get to see the car on the road, ready, running and shining? Please post a fourth video. I have fallen in love with your Volvo! Ove, Sweden
Fuel pump sounds great! Good work PAI.
I like the Swedish accent perfect for a Volvo repair video
My dad had the sedan version of this car until he developed epilepsy, I miss it as we had great memories driving it. It had the same colour like this car.
The flasher is a old fashioned bi-metalic strip circuit breaker (a electromechanical multivibrator). The turn signal circuit cycles by a function of the amount of current that flows through the bi-metalic strip. A overloaded or shorted turn signal circuit to ground will cause the lights to flash rapidly. Some thought should go into rewiring the trailer lights and possible auxiliary power...those little wires can only supply a small amount of current.... In USA the Department of Transportation dictates (since a lot of light duty trailers have "electric brakes": things get complicated for "failsafe" operation). Approved designs are available.
We got a load of manuals and guides for Volvo 740 and 940 and more on the channel and the website if you need. That haynes manual are a bit hard to understand and there is some really bad pictures in that book.
Interesting video. Waiting for the other one tomorrow! Thanks.
A German market 745 is rare and so cool!
this is such a pretty car, I hope you will be able to fully restore it and pass the inspection! :)
Ah, I miss my Volvo brick. If you do replace the in tank pump, upgrade it to a 740 turbo's pump. They flow a lot more and help reduce the strain on the main fuel pump. :)
Im enjoying this videos a lot! thanks for doing them =)
Good video, love an old Volvo.
Love that car, I hope you'll turn it into the best 740 ever eventually. WIth TPAI mods and Vault Tec components obviously.
These cars are amazing! I used to have one, and now I drive a 240. My 240 drove for several years with a loose carburettor.. the carburettor was just sitting on top of the engine with loose bolts ;).. I also made a video about diagnosing that weird problem, which ppl might find useful..
Great video as always !
Absolutely positive. The pump should shut off after a few seconds if the ECU looses cranck signal (key in II pos).
I'm an authorized car technician so i'm pretty sure on this. The relay should have a control signal from the ECU directly or via other control circuits. I suspect that someone has damaged the original wiring system when doing a repair job and not being able to correct the problem they probably added wires to the system to make the pump run uncontrolled from ignition switch (key pos II). It makes no sense that fuel pump runs for a few seconds in AUX ( I ) position. This is how the fuel system should work when key is in pos II and the pump should not run at all in pos 1 (AUX)
I hope you love reading wiring diagrams cause this seems to be a complex problem. I would suggest that you first follow the circuitry activating the coil in the fuel pump relay all the way to the ignition switch. I bet you will find a fuel shut of control relay somewhere in between. Pay especially notice to the wiring and the color coding on these components. Good luck!
Big thumbs up here. Definitely check that the wiring is correct. The fuel pump should not run until in Pos 2, and then just for no more than 2 seconds or so. I completely agree that someone has likely found an issue and applied a "work around" by adding a wire to make it run all the time. I might even consider that the fuel pressure sensor (if equipped in this car) went bad and this was how they fixed it.
Great video! You should do some cleaning on the motor and make a video about that process. Thanks for the tips!
Good job.
Be nice to get a fuel pressure gauge on the fuel rail, then compare to specs. However, it appears the fuel filter was the urgent problem. I always wanted a 740 wagon. I had a 142, a 164, a 244 wagon, and an 1800S.
Check that timing belt.
I think that the fuel pump may have an internal pressure switch that shuts off the pump when the line to the fuel distribution system is sufficiently pressurized. You should be able to verify that with the new pump on the bench.
FYI: On many GM large SUVs or pickups vehicles there is an electric fuel pump near the left rear wheel that is fairly loud and does seem to run continuously.
As most flasher units use bi-metallic strips as the timing element, the current load of lamps determines the flashing rate. When a lamp burns out you will notice that the flashing rate slows down. The relays allow the flasher to see the normal complement of lamps while providing a separate circuit for the trailer tail, brake and turn signals.
I think that i heard a sound related to a mis-adjusted or worn belt running off of the crankshaft pulley. The video showed the alternator or power steering pump belt with too much play while running.
It is becoming popular to substitute a computer tablet for the source signals for the sound system. The tablet usually has a navigation app that uses the device GPS system to function. Also any stored music can be played through the former CD or cassette inputs. The Bluetooth capability may make a legal hands-free telephone connection and/or play tunes from your smartphone.
I noticed that you mentioned that you lost your job from your previous employer; I hope that you found something better in Koln. (I used to have a 1974 Mercury Capri (Ford) that was assembled in Koln (my most reliable car until I let the Los Angeles California air embrittle a short section of rubber fuel hose that began burning while driving on a freeway (bahn) with my infant son in a rear car-seat. I got him out but could do nothing to extinguish the flames while holding my son (lost the car-seat too).
I have yet to watch episode three of the Volvo project. good luck. I'm not a mechanic, but a retired videotape & systems technician (they call us engr.s but I am self taught; no degree).
I agree the original shop repair manual is always good for repairing cars.
Great video!!!!
the noise from a pump like that can be caused by cavitation. It could be that there is a pinhole in the suction side fuel line. These often don't leak owing to vacuum pressure but do admit air. Further - the pump may not be timed but is switched via a pressure transducer at the intake manifold or carburetor (if old school). Owing to air being compressible the pressure may be insufficient to trigger the transducer causing continuous running. I only mention this to prevent you from swapping working parts and not fixing it! BTW - I'm not a mechanic but a process pipework engineer...
yup, i second that.
I agree however I have seen some cars that have a pumps that do constantly run and whatever fuel is built up pressure wise recalculates back to the tank. I've only seen this happen to older Dodges and I don't know much of anything of Volvo.
I've also seen it caused by the tank lift pump as mentioned in the vid. Suction from the main pump lowers the pressure in the line from the tank causing the fuel to pretty much boil, hence the cavitation noises.
Even Fuel injected volvos in the 70's had fuel shut of so there is definitly somthing really wrong with the electrical system on this 740 90mod
Hmmm, might be worth checking. I had an F reg ford granada that had a colision detector module next to the boot latch that triped when every time a heavy tool bumped about in the boot, i wonder if it may have been bypassed in the same peculiar way as the indicators where, as towing would have definatly triped my granada on every bump. However go with the experianced, the tank pump not delivering enough volume of fuel to the fuel injection pump does make sence.
I would also take a quick look at the fuel pressure regulator (FPR). There are 2 lines, 1 goes to the FPR from the tank, and 1 goes back to the tank (the return line). Unplug the return line from the tank and put it into a canister of some sort (or unplug it from the FPR and run a spare line into the canister). Start your car, there should be a large amount of gas coming out of this return line. If there is not, your FPR is bad and must be replaced. A fuel pump is capable of delivering MUCH more gas than is needed, the FPR sends the excess back to the tank, this could be damaged and not allowing the excess back to the tank. It's essentially free to check and not overly difficult.
As mentioned in another post the sound from the fuel pump could have been cavitation, it sounded like that and maybe you were getting some air in through the old filter.
I am looking forward to seeing all the repairs you end up making on this vehicle. It looks like the car is not bad from a rusting/rotting problem.
I think it might be worth seeing about buying some fuel hose and re-doing all the fuel lines when you do the pumps. They really don't look very good. If you don't have a tiny fuel leak or air getting into the system I think you will. Also when you take the tank pump out it might be worth flushing out the fuel tank because after 20 years the tank probably has some crud in it.
I think for a modest amount of money and a bit of time you could turn that Volvo into a good reliable car. I think it was a pretty good find. A lot of these have since gone to the scrap in the UK because their owners wanted something newer or couldn't afford to fuel them.
can't wait for tomorrow video
nice job
The relay turns on and off to adjust for fuel line pressure so excess pressure won’t fold engine or overwhelm fuel return system. Part of what makes it meet California emissions.
I'm not 100% sure on Volvo's, but on most EFI cars, the engine control module energizes the fuel pump relay, and thus the control logic is in the ECM, not an external circuit.
Many will do a pump prime at key on then shut off, and wait for an ignition or crankshaft position sensor indication that the vehicle has started. At this point the fuel pump will be energized continuously until the engine is shut off or stalls.
The mosfets that control this relay in the ECM do on occasion fail, and some mechanics will simply wire the fuel pump relay directly to a key on power source rather than repair or replace the ECM.
In this case, the fuel pump will run continuously whenever the key is on, rather than prime and run only when the engine starts.
The risk is in an accident the fuel system will remain pressurized and pump fuel whereas factory configuration will shut off fuel if engine is stopped. Also if you have a leaky injector, the cylinders or upper intake can flood in a key on, engine off state.
Just my 2 cents, but verify that fuel pump relay exciter wire runs to ECM, and verify ECM is putting out 12v as intended.
Nice car😊
Once I had suspect a problem with the white relay. I guessed that the coil inside is getting weak, so I adjust the related parts in the relay to compensate for it. Unfortunately I forgot what exactly since it was long ago. It works anyway. So much custom relay this car have.
The fuel pumps are controlled by the Engine Computer, the ECM, through the Fuel Pump Relay. Pretty sure the fuel pump isn't suppose to run all the time. Normally they run for about 5 seconds and if there is no crankshaft sensor input indicating cranking/running, then the ECM shuts the pump off when the Fuel Pressure Sensor or Switch says that the system is pressurized. They did this to keep the fuel pump from running all the time and to ensure that there is good line pressure to reduce crank times.
Anyway, change the in-tank filter at the VERY least, preferably the whole pump too given it's age and the low cost of a replacement pump. Most likely the in-tank filter is clogged and reducing pressure to the second pump causing cavitation when the fuel boils in the partial vacuum. You can hear it when the pump runs, that's what the Whhiirr - Grrrrr- Whhirr noise is. The Grrrs are the cavitation. This is one of the biggest problems with two pump systems.
For the inspection in Germany you need to have a cover over the positive connection of the battery, as far as I remember (something to add to the list ^^)
Please cut open that fuel filter with a hacksaw! I was getting anxious to see what is inside.
keep the new fuel pump, but make a small adaptor loom so you dont have to change the old wiring; best of both worlds!, the fuel pump would be timed by pressure not electronics, so would be a valve/solenoid inside the pump, again, try the new pump and see if the situation changes.
The fuel pump fault may be caused by a faulty air flow sensor. If it's Bosch L Jetronic or a similar moving vane type there is a switch under the cover that detects air movement and switches the pump via the relay and ECU.
WELL DONE MATE§§§§
Oh yeah, don't touch the in-tank pump unless you have to. I guarantee that each of those fuel and return lines are going to need repair or replacement if you disconnect them, and the lines on some cars can be very long and hard to get to.
I have a 1990 Volvo 760 GLE with the V6 engine. The car has about 240,000 miles with the original fuel filter. Your fuel filter and fuel pump is configured just like mine. Your video is helpful in showing that these parts can be removed as a unit, then placed on a bench for further disassembly. However your video did not show how you disconnected the power cable wire to the fuel pump?
Hi mate, It looks like you have found yourself a very nice example of a Volvo, given that cars in Europe have a lot to deal with like salt, acid rain, and mechanics that don't care about your car . I have always liked the Volvos, but for their being quite underpowered for the bulk of the vehicle, power to weight ratio. I think I would like to see them with a nice V8 in them. I think that you will have to find some good replacements for all the plastics, if it has not broken now it will break soon, or when you take it loose. Unfortunately, a lot of mechanics are not very good at looking after the plastic panel parts of the car.
my Volvo 940 wagon is surprisingly a chic magnet, stone really wholesome beauties give me long smiles and even compliment the car,,,
Great job fixing the lights and filter :-D
People modify things without thinking, best to rip out the non standard systems :-).
I would have made patch cables for the new pump from ebay, converter cables :-).
I agree with this. My view on repairs and restorations is that "factory standard" is not necessarily the best standard, it was the most cost efficient production standard.
the fuel pump doesn't turn off via a timer. Most "modern" vehicles the pump turns off once it reach's a certain fuel pressure. I don't know about your car in particular, but it may or may not be designed that way.
The other way it's done is for the pump to run 100% of the time, and a fuel pressure regulator returns excess fuel to the tank via a return line.
If your not able to get a refund on the pump you already bought, and are unwilling to change the connector on the car itself you might consider making a adapter. You might even be able to use the connector from the old pump, along with a few bits of wire and new connectors for the new pump.
the fuel pump turning off is probably linked to fuel rail pressure. the filthy filter was probably preventing the rail getting to pressure. that old filter was probably putting too much strain on the filter or cavitating.
I have the Haynes manual, but would like to know if you can get a 760Turbo, awesome work.
most external fuel pumps after market at least come with differ plugs even the internal ones as well.
Turning the ignition back should only turn on accessories radio and so on.
Forward one time should turn the fuel pump on for a very short period of time less than 30 seconds.
Turning it Forward twice from the off position the fuel pump will run constantly you will also get check engine light because normally Click 2 is where the car would normally be at when running after starting the engine.
A consistent amount of fuel is sent to the engine any fuel that is not used will be sent back to the gas tank. That is why you see two gas lines.
Write on the filter when it was changing. I saw ChrisFix do what.
Are you thinking of changing the timing belt? I seem to remember my 440 wasn't too difficult to do.
The fuel pump shouldn't keep running with the ignition in run. Whatever drives that relay should have an RPM input as well as an ignition switch input, and shut the pump off if the engine stops running. This helps prevent a fuel fed fire in a crash.
Fuel injected engines wont run without fuel pressure, so the pump HAS to run when the key is turned on.
Right, it should run for a moment and then shut off. When the system which runs the fuel pump relay senses the engine turning it turns the fuel pump back on.
PS. What I definitely want to do is to replace the fuel filter. Can you share how you disconnected the fuel hose from each end of the filter and reconnected. Are there any special tools or parts needed? Thanks.
though i'm glad you fixed things to your liking i do enjoy the idea of the spastic blinkers. Volvos are such sedate cars, it's like yours had too much caffeine.
cheers for that comment mate! got me laughing and sounding like a braying donkey having an anxiety attack :)
Man that fuel pump sounded like something out of a horror movie.
Really enjoying these videos
I think the inner shell had rusted away in a spot that sucked in air. And/or the layers where broken.
Can you make a video then you are painting the bumpers??
No more hesitation on wide open throttle??
Asking as i own an 88 that's fuel pump sounds like that and its cutting out when on wide open throttle at low speed only
so im thinking it would be the fuel filter blocking enough fuel from going to the rail!
Pls respond i know its an old video but there isnt much content revolving around diying 740's
H
Hi dreamsun. My 740 has only one intank fuel pump as it is a Regina system. I don't know if yours is. For quite sometime I have been having a hesitation ( backfire too) when the throttle is wide open . I will be fixng this soon ( after a lot of parts swap). It seems to me after extensive research on the internet , that the pulasation damper may be leaking. This is the ( some folks call it a pillow, others say it looks like a mini old ford brake master cylinder cover) little thingy that is attached to the output of the fuel pump. Many owners have had succes just removing this and installing a SUBMERSIBLE fuel line in place. I will be fixing this soon as it is not a priority now. Hope this helps
the fuel pump sounds like an old hard drive after your replaced the filter.
Rinoa Super-Genius omg lmao ahahhahahaha
It seems from the video you changed out the fuel line while replacing the filter. Did you find a new line or roll your own?
Nice, i hawe two old volvo, unfortunatly older model then this so i don´t know much of the 740 series, but there are lot of cheap spareparts around here in the origin country of Volvo...
I think i possibly hawe some old intake parts, that i once found on a scrap Yard, for the 740 somewhere...
Scrap cars are wery common here since we (in Sweden) does not hawe that law that provide people from letting old cars rust on tha backyard so many people (like me for example...) saving old cars for spare parts, one can ofte pick one up sheep i one need bigger or more expensive parts and then send the rest of it to metal recycling or sellin the remaining part weither.
Unfortunatly i am more or less constantly out of money so i cant send anything at the moment, but i can give You the intake bar for free if You want it and possibly some other person can pay the shipment.
Just in time.
That car sure hasn't seen maintenance in many years!! Fuel filters must one of the most neglected service parts, most likely because of the location and relative difficulty in replacing them. Also garages charges for such items are excessive. I wouldn't like to live in Germany from a car owning perspective, the TUV is very severe! The UK actually imports part worn tyres from Germany because when they fail there they are still legal in the UK!!
Why didn't you just use crimp connectors on the original loom for the new fuel pump?
What happend to the old Opel you had ?
Could not you figure it out that fuel pump has a timer from the circuit diagram?
Edit:If you upload hi-res picture of circuit diagram i like to see.
Hi, my Volvo 740GL petrolengine( year 1986) will not shut OFF on many occasions. It will switch off if i turn key ON and immediately turn the key off. Sometimes i must repeat this action several times!! Any suggestions would be greatly appreciated as i have not found a solution yet, even after having it serviced at Volvo Distributor in my country
Lino Stafrace im guesing your ignitionlock is vorn out so i advice you to go to The local junk yard an find another igniton lock they are rely cheep
Where can one buy those green books in English?
I know nothing about Volvos, but most vehicles will run the fuel pump until the system is pressurized, then shut it off until the engine is started.
Do you still have this car?
I always thought that the fuel pump shuts off automatically due to a pressure switch, so it builds up fuel pressure and then, when the necessary pressure is reached to start the engine, it will shut off. If that is the case, then there is no timing circuit needed for that, but some fuel pressure sensor on the engine. In that case, "it shuts off after a few seconds" would have been to describe "it shuts off when the correct fuel pressure is reached". But then, I didn't even look at the engine when it was shown in the video, in order to see whether it is carburated or fuel injected. I am guessing the latter, which would mean that it is electronically controlled by some kind of ECU. Look in the service manuals if you can see a fuel pressure sensor somewhere on the fuel rail or whatever type of fuel injection it may use, and see if that maybe needs replacing?
Disclaimer: I'm just guessing here though, I've only got theoretical knowledge, never done any serious work on a car. It may be I'm right, or it may be I'm totally off and it's a completely different issue, or possibly even none at all.
you are correct it builds pressure and stops, i believe that mechanism is in the pump, and the pump is worn so leaking pressure back from its valves and not shutting off, he should use the new pump seeing as he bought it, i see no issue on a small wiring mod to use it, i doubt it will ever need replacing again to worry about.
The pressure switch can be on the fuel rail, in the line, in the pump, or in the tank. Depends on where they put want to put it. Today on most systems the ECM will time out the pump if they don't get a crank signal after about 5 seconds regardless of the fuel pressure to keep from running the pump if there is a leak in the line somewhere.
jusb1066 Alright, but the problem with the wire mod is that this is Germany. He briefly mentioned the vehicle safety inspection (just as "inspection"), and any part that isn't stock has to have a dedicated permit of operation (usually, spare parts or modifications come with it or are not legal to be used), which you won't get for a wire mod, so it could mean the car is never allowed on the road again, because he cut off the plug from the wiring harness to the old fuel pump.
Seegal Galguntijak
then i dont get how it was allowed to have all that wiring badly modified for the turn signals and terrible radio fitting job, but two new terminals on a fuel pump is not allowed....we have a EU vehicle safety inspection in the UK, but well made terminals on a new fuel pump would not be an issue
jusb1066 It was a presumption that he could get problems with that. I think it would stronly depend on how well the wiring is done, how well it's protected from the environment and so on. But the turn signals probably weren't legal either, how it was on the road like that remains a mystery to me. But, as always if you know the inspector, he can overlook certain things...
The radio is not relevant for the safety and operation of the vehicle, so there you can get away with almost anything...
Pressure switch not timer.
i do not understand why he installed the relays there.. i have the same model of the car, and my trailer wires are tapped into the rear light wires and the blinkers work just normal that way, without any addition relays.. strange
I think the previous owner cut the turn signal wire, wired the relay in series straight to a ground, then wired both the turn signals and the trailer lights to the load side of the relay. That caused less resistance in the turn signal circuit and the flasher relay to work faster. They should have just spliced the relay into the turn signal wire and left the bulb alone.
I wonder if today's cars have these service manual with this level of details.
yes. but normal leased online today. + tool. an all car packet easy 5-10k euro a year.
And even if they do, you'll need a special computer to program all the different computers for different purposes. These things (the ones that can do almost anything) are really expensive, like in the 3 to 4 figure range. And if the car is from any brand of the Volkswagen group, the universal computers don't even help, because they've got their own special system in the 5-figure-range. At least that's what a buddy of mine who works in a repair shop told me.
matador battery? kkkkkk matador means killer in portuguese and spanish ! greetings from brazil
howdo I improve the poor fuel economy? 16miles per US Gallon,,, on a 940 Non Turbo wagon
If I recall correctly the fuel system has the pump, the filter and an accumulator. When going to position 2 on the ignition switch the pump kicks in and if healthy charge the accumulator and when system pressure is achieved I believe a pressure sensor cuts the pump off. Of course if you start the engine then the fuel flow will drop the pressure and the pump will kick in immediately and the accumulator then essentially acts as a pressure damper. Long time since I had a Volvo so forgive me - and I am get ting old as well.😀👍
Wow, that is some rusty POS...
I have big respect for people who get stuff like that working again or even in a perfect condition...
I am far too lazy for that kind of stiuff...
I just installed a new headunit into my car and had to find a switched 12V contact for that and run a wire. 1h worth of work for me and i hated it...
meh, at least the body won't rust.
Most cars are completely gone when they even reach 20-25 years. I repaired many cars and volvo is on top of my list of durable and easy to service cars. Have seen old and new ones with over half million km with very few worn out parts. The old 700 series is also a nice car to drive, especially with some small mods to improve road holding.
for it's age in a temperate climate it's in remarkably good knick.
zoidberg444 Yep, i think it is actually a very good time to buy a car currently, old cars are cheap and still in reasonable condition for the most part. Also they are realtively easy to work on and super high quality compared to modern cars. Still i had to buy a relatively new car because i hate working on them...
+Botje I have a 1989 VW Golf Mk2 and it still has not rotten
your fuel pump should shut off. you should only hear it for a few seconds after you turn the key (thereby priming the pump). the only situation in which I've seen a fuel injected vehicle with a continuously running fuel pump is in racing cars with a modified fuelling system.
my guess is that the PO rigged up some kind of jumper to switched power in order to keep the pump on. no clue as to why someone would do that though.
my 1989 325I has a dual pump setup like yours, and I would love to see how bad the inside of that filter looks. I changed mine 30 k after buying it, and threw it away without thinking about it.
One thing I like about VW/Audi is that you can download all the service/repair information for a nominal fee (I think 10eur or something), including schematics.
This Volvo would just be a little too old and too rusty for me.
God, I don`t understand any of this stuff. Reading music is easier then reading those diagrams...
I love saving old stuff, but man I can't see anything in that car, is just old and ugly.
Keep it up, good content anyway
ollythebest94 .....1 sec. into the vid.,,,,,,I'm with you.
Volvos rule :)