The coolant temperature sensor should be at 2.4k ohms cold and 200 ohms at normal operating temperature. Corrosion at the connector is usually the problem for over rich issues. I installed a 0 to 2k ohm potentiometer in line from my temperature sensor to the ecu so I could increase the pulse duration on demand when I want to go out and play. I have a another AFM that I have adjusted the potentiometer and flap spring tension for performance. The screw you are adjusting is for CO mixture at idle. It is an air bypass (unmetered air). By the way, if your 280z all of a sudden starts huffing out black smoke and stalls even after repairing your temperature sensor connector you may have a PC board issue with the ECM. Usually you can slam the driver's door and replicate the problem. I've experienced a lot over the 40 plus years of owning my 77 Z. Also been a Nissan master tech since 1987. You're good, keep pumping out the videos brother.
The flapper box is called a vane air meter. I have the same setup on my turbo swap ford ranger. Totally gonna check this procedure out! Thanks for the info! Priceless
Man you saved me so much time. I cranked my 82 280zx over for the first time and it was ridiculously lean but adjusted it, started sounding better at idle and when I’m going through the gears
I FINALLY GOT MY Z RUNNING!!! I haven't checked into the channel for a couple of weeks, I've been to busy swapping in the new block. So here I am about to start tuning and when I searched for "280Z AFR" OF COURSE you're working on it right now. I got my Z just as you started working on mine and have coincidentally been working in parallel to your restoration series. Let me stop rambling and just say Thank You for keeping up with the uploads. Will resume watching them weekly.
Great video!!! I’ve been having some issues tuning my 1982 280zx to run smoother. This definitely helped out. I appreciate the video and the content you put out.
Anybody struggling with these type of vehicles I will let you know that most of the aftermarket fuel pumps especially the Carter brand do not have a check valve in them so if your fuel pressure is bleeding off you need to install an inline check valve right after the fuel pump fuel pump pressure should be about 39 PSI with no vacuum applied to the regulator and it will drop to about 29 or 30 with vacuum applied I've been working on one for a while over Rich when I got there due to a faulty temperature sensor connector soldered wires directly to the sender so there's no way there can be a bad connection now the vehicle exhibits lean conditions off idle you can adjust the air-fuel mixture box but what I did was added 1000 ohms to the temperature sender so when the engine is warm it gets about 1.5 K to the computer and that solved all the lean running issues for me if you're going to mess with the air-fuel mixture box you better be a good mechanic sometimes things get old and get a little bit out of whack and wiring it's worn on these cars over the years it's always best to check the basics first make sure your valves are adjusted correctly check the timing chain to make sure it's not stretched or somebody put it out of whack no vacuum leaks excetera all the years I worked on these cars back in the days the most common problem was over rich condition due to bad connection at the temperature sending unit also do yourself a favor and get inline fuel filter between the gas tank and the fuel pump it's hard to find a 7/16 fuel line filter but they are out there you can stretch a half inch inline filter in there it's a little difficult with the original hose but it can be done make sure you don't put it on the pressure side
You are not reducing idle air to the engine to richen the fuel mixture, that could only be done at the throttle. You are decreasing the amount of air that is bypassing the air flow meter. The same amount of air is going into the engine, but now more of it is actually going through the flap of the AFM and being accounted for. Now that the ECU can see this air, it adds more fuel to correct the lean condition.
From my understanding the coolant temperature sensor in the thermostat housing does not play a significant role in the air fuel mixture ratio of the engine unless it is a Canadian model. U.S models base the air fuel ratio mostly on the CHTS sensor which is located on the passenger side of the engine in the head between spark plug 5 and 6. Often times replacing this sensor or cleaning up the connection points will get the car running well again. If it’s a Canadian model car then I have no clue.
The WTS does have an affect on the After-Start Enrichment by the change in its resistance value, thus changing the Injector open time or pulse width. The CHTS was introduced on S30’s built after 04/77 or 07/77 for the 78 model year and on until the introduction of the S130 in 79 for the US market.
First, I Love your content. It feels totally honest which I think is cool. But dude, you would be way happier with dual SU dome-tops, or Triple DCOE40s. Once you can restore and balance them they are both awesome. This antique fuel injection stuff seems to be a nightmare.
My 76 Does not have an idle mixture adjustment like you showed in the video. Unless it is behind the plug or some such where the screw is located on yours. I'll take a picture and try and get it to you.
Your Fuel Injectors are possibly not getting a signal to open. This can be validated by using a Noid light connected to the EFI harness to check for the presence of a a signal from the ECU at the Injectors. Failing that you need to start at the beginning to determine if your ECU is getting a minimum of 10V while cranking. In addition you’ll need to do the necessary troubleshooting steps defined in the FSM for a No Start condition
My car starts cutting off when i turn it on it starts cutting off i changed all the holes and and its still the same it cuts off u think the problem is from the afm
before the idle AF adjustment did you try removing the oil filler cap while the engine was idling? If so try that again and see if you notice any difference from before adjustment. On mine with what I will call the rich running AFM (great for smooth idle and high vacuum at idle) I noticed that removing the cap barely had any effect on the vacuum and engine while idling. I replace the AFM with what I will refer to the lean running AFM (again this is only as it relates to idle) and I had an rpm drop, vacuum drop and overall slightly rougher idle. Removing the oil filler cap with the lean running AFM will result in nearly instant stoppage of the engine. Now the conundrum, Are Datsun 280z EFI setup for lean running idle at the factory (perhaps as a preventive measure for emissions testing)? the reason I speculate this is most folks report engines that will stop running as soon as the oil cap is removed, implying a typically lean idle mix. Or is it something with the fuels being used today? Frankly I can see no reason to keep the lean burn at idle as most of these old cars exempt from emissions testing (if that is a problem with the rich AFM, I don't know as I have no way of testing the exhaust gas for emissions). The rich burn certainly feels better when sitting at a stop light, but other than that and the knowledge that the car is operating more efficiently I am not sure if it really matters. Both the rich and lean AFM have the same overall performance in every other respect. there is no popping or exhaust backfires, as the only mix that seems effected is the idle, hence as soon as off idle the ECU relies on other sensors to enrich the fuel mix. I will prob go back to the rich setting just for the slightly smoother idle, sitting at traffic lights is pretty common around here.
Yo yo yo saying was sup. And my z is running and brakes fix however cyn i can here feel its misfire. So thats next oh got to test drive her found out my dashboard lights dont work and mph klm doesnt work but rpm does.
Sorry for the late response man. My dashboard lights don't work either, I just try not to drive at night... for now. My speedo works, it's just not that accurate and it bounces a lot. Will eventually make a episode about that, but just use your phone as a speedo for now if you really need it. The misfiring can be a lot of different issues. What have you tried so far?
Hello, I appreciate all of your videos! thank you so much for all of them.. ive been following all of your episodes and it has been helping me.. btw if you get a chance please check out my videos .. am currently trouble shooting an intermittent stalling issue and a poor a/f ratio .. thank you!
The coolant temperature sensor should be at 2.4k ohms cold and 200 ohms at normal operating temperature. Corrosion at the connector is usually the problem for over rich issues. I installed a 0 to 2k ohm potentiometer in line from my temperature sensor to the ecu so I could increase the pulse duration on demand when I want to go out and play. I have a another AFM that I have adjusted the potentiometer and flap spring tension for performance. The screw you are adjusting is for CO mixture at idle. It is an air bypass (unmetered air). By the way, if your 280z all of a sudden starts huffing out black smoke and stalls even after repairing your temperature sensor connector you may have a PC board issue with the ECM. Usually you can slam the driver's door and replicate the problem. I've experienced a lot over the 40 plus years of owning my 77 Z. Also been a Nissan master tech since 1987. You're good, keep pumping out the videos brother.
The flapper box is called a vane air meter. I have the same setup on my turbo swap ford ranger. Totally gonna check this procedure out! Thanks for the info! Priceless
Man you saved me so much time. I cranked my 82 280zx over for the first time and it was ridiculously lean but adjusted it, started sounding better at idle and when I’m going through the gears
I FINALLY GOT MY Z RUNNING!!! I haven't checked into the channel for a couple of weeks, I've been to busy swapping in the new block. So here I am about to start tuning and when I searched for "280Z AFR" OF COURSE you're working on it right now. I got my Z just as you started working on mine and have coincidentally been working in parallel to your restoration series.
Let me stop rambling and just say Thank You for keeping up with the uploads. Will resume watching them weekly.
Thats awesome dude, happy to hear it!
Great video!!! I’ve been having some issues tuning my 1982 280zx to run smoother. This definitely helped out. I appreciate the video and the content you put out.
Really great explanation. Thanks!
I have pretty much the same issue with my AFM on m30b35 engine.
You saved me a lot of time and effort.
Good luck!
Anybody struggling with these type of vehicles I will let you know that most of the aftermarket fuel pumps especially the Carter brand do not have a check valve in them so if your fuel pressure is bleeding off you need to install an inline check valve right after the fuel pump fuel pump pressure should be about 39 PSI with no vacuum applied to the regulator and it will drop to about 29 or 30 with vacuum applied I've been working on one for a while over Rich when I got there due to a faulty temperature sensor connector soldered wires directly to the sender so there's no way there can be a bad connection now the vehicle exhibits lean conditions off idle you can adjust the air-fuel mixture box but what I did was added 1000 ohms to the temperature sender so when the engine is warm it gets about 1.5 K to the computer and that solved all the lean running issues for me if you're going to mess with the air-fuel mixture box you better be a good mechanic sometimes things get old and get a little bit out of whack and wiring it's worn on these cars over the years it's always best to check the basics first make sure your valves are adjusted correctly check the timing chain to make sure it's not stretched or somebody put it out of whack no vacuum leaks excetera all the years I worked on these cars back in the days the most common problem was over rich condition due to bad connection at the temperature sending unit also do yourself a favor and get inline fuel filter between the gas tank and the fuel pump it's hard to find a 7/16 fuel line filter but they are out there you can stretch a half inch inline filter in there it's a little difficult with the original hose but it can be done make sure you don't put it on the pressure side
Very nice good to see shes running good
Yes sir!
You are not reducing idle air to the engine to richen the fuel mixture, that could only be done at the throttle. You are decreasing the amount of air that is bypassing the air flow meter. The same amount of air is going into the engine, but now more of it is actually going through the flap of the AFM and being accounted for. Now that the ECU can see this air, it adds more fuel to correct the lean condition.
Super helpful video!! Thanks
Where did you get ignition power for the gaug
From my understanding the coolant temperature sensor in the thermostat housing does not play a significant role in the air fuel mixture ratio of the engine unless it is a Canadian model. U.S models base the air fuel ratio mostly on the CHTS sensor which is located on the passenger side of the engine in the head between spark plug 5 and 6. Often times replacing this sensor or cleaning up the connection points will get the car running well again. If it’s a Canadian model car then I have no clue.
The WTS does have an affect on the After-Start Enrichment by the change in its resistance value, thus changing the Injector open time or pulse width. The CHTS was introduced on S30’s built after 04/77 or 07/77 for the 78 model year and on until the introduction of the S130 in 79 for the US market.
First, I Love your content. It feels totally honest which I think is cool. But dude, you would be way happier with dual SU dome-tops, or Triple DCOE40s. Once you can restore and balance them they are both awesome.
This antique fuel injection stuff seems to be a nightmare.
Thank you for this!!!!! Perfect!
My 76 Does not have an idle mixture adjustment like you showed in the video. Unless it is behind the plug or some such where the screw is located on yours. I'll take a picture and try and get it to you.
So the car should be at around 15.5 at idle and 14.5 at highway speed?
How did you run your gauge after? Did you use a 12v switched source or straight to the batt?
Does the AFM move when cranking the engine I think mine is out of wack and my 280 won't start
Hi hav. gas at fuel rail but when cranking none going in engine . what prob. do u think hav. computer or air fiow . any help will be app.
My first guess would be the pump. Second guess is clogged filter.
It might be the fuel lines are reversed if you are getting fuel to the fuel rail. I am a z enthusiast. If it isn't that I can help.
Your Fuel Injectors are possibly not getting a signal to open. This can be validated by using a Noid light connected to the EFI harness to check for the presence of a a signal from the ECU at the Injectors. Failing that you need to start at the beginning to determine if your ECU is getting a minimum of 10V while cranking. In addition you’ll need to do the necessary troubleshooting steps defined in the FSM for a No Start condition
You adjus the idle mixture bypass screw using a CO meter. Please read the Factory Service manual.
My car starts cutting off when i turn it on it starts cutting off i changed all the holes and and its still the same it cuts off u think the problem is from the afm
I suspect your vacuum numbers will have improved as well.
I'll check again!
before the idle AF adjustment did you try removing the oil filler cap while the engine was idling? If so try that again and see if you notice any difference from before adjustment. On mine with what I will call the rich running AFM (great for smooth idle and high vacuum at idle) I noticed that removing the cap barely had any effect on the vacuum and engine while idling. I replace the AFM with what I will refer to the lean running AFM (again this is only as it relates to idle) and I had an rpm drop, vacuum drop and overall slightly rougher idle. Removing the oil filler cap with the lean running AFM will result in nearly instant stoppage of the engine. Now the conundrum, Are Datsun 280z EFI setup for lean running idle at the factory (perhaps as a preventive measure for emissions testing)? the reason I speculate this is most folks report engines that will stop running as soon as the oil cap is removed, implying a typically lean idle mix. Or is it something with the fuels being used today? Frankly I can see no reason to keep the lean burn at idle as most of these old cars exempt from emissions testing (if that is a problem with the rich AFM, I don't know as I have no way of testing the exhaust gas for emissions). The rich burn certainly feels better when sitting at a stop light, but other than that and the knowledge that the car is operating more efficiently I am not sure if it really matters. Both the rich and lean AFM have the same overall performance in every other respect. there is no popping or exhaust backfires, as the only mix that seems effected is the idle, hence as soon as off idle the ECU relies on other sensors to enrich the fuel mix. I will prob go back to the rich setting just for the slightly smoother idle, sitting at traffic lights is pretty common around here.
Woo called it.. I win!!
I wish I had a prize for you brother haha
Yo yo yo saying was sup. And my z is running and brakes fix however cyn i can here feel its misfire. So thats next oh got to test drive her found out my dashboard lights dont work and mph klm doesnt work but rpm does.
Sorry for the late response man. My dashboard lights don't work either, I just try not to drive at night... for now. My speedo works, it's just not that accurate and it bounces a lot. Will eventually make a episode about that, but just use your phone as a speedo for now if you really need it.
The misfiring can be a lot of different issues. What have you tried so far?
Restoration For Beginners fuel injector issues withtiming it wont advance past -3 it gos backwards from there so its off a tooth. Been busy myself.
dude im waiting for another vid please i miss your ???
Sorry, it's coming in the next hour!! I skipped a week because it got a little busy at work.
Thumbs up!!!
Yes sir!
Hello, I appreciate all of your videos! thank you so much for all of them.. ive been following all of your episodes and it has been helping me.. btw if you get a chance please check out my videos .. am currently trouble shooting an intermittent stalling issue and a poor a/f ratio .. thank you!
Hey did u ever figure it out?
Not my car.
Why can’t you just show how to adjust the fuel pressure I don’t need to see all of this