once every couple generations, a man comes along that revolutionizes an industry and ALSO has a passion to teach it to everyone eager enough to learn it and listen to it. Mr. thompson you are a gift
Once you know it's fuel Delivery first thing I do is pinch the rubber return line to the gas tank and watch the data quick way to check the regulator Holds the volume in the fuel rail 👍
Man i love these videos. Bernie has such passion for thinking through problems to find the fix. Amazing! Anyone who doesnt believe in using scopes is doomed
Hi Bernie great video. I I'm alittle confused with some of the other people in the comments about the fuel pressure reading showing good with a bad regulator. Thanks for the awesome video as always..SAVAGE
Fuel pressure at the rail is good, but the regulator is letting it bypass it afterwards and return to the tank instead of keep pressure on the injectors
I have a 1991that I brought brand new, when last year injector #3 shorted and went to "technicians" who did not know how to analyze this primitive OBD 1 fuel injection system, and ended up doing it myself, buying only OEM sensors, as process of elimination. I swear I will never trust OBD2 technicians who do not show remorse, charging high prices, plus mark-up for counterfeit Chinese injectors, and sensors. I spent about $1,500 and swapped those sensors, all of them OEM which included ECM. MAF, TEMP, IAC, TPS, AIR TEMP, AND OXYGEN. I even had those new injectors tested, from a shop in Torrance, California who gave me a detailed report of the performance of each injector, and with my confidence boosted I passed emissions with flying colors. I am new to your channel and I am subscribing, I only whish I did before going to the scum bag "technicians" who only ripped me off.
Big fan of your channel. Moral of story is, it takes 8k worth of equipment these days to fix 800 dollar truck, plus price of time invested in acquiring the knowledge on how to. My 2 cents Go figure ...
First of all mad props to Mr. Thompson for his excellent diagnostic routine. My Issue I have with the FPR (Fuel Pressure Regulator) being at fault is this: The Fuel Pressure was being monitored by a pressure transducer into the scope, if the FRP was just full on returning at pump rate, then when the key was switched on and engine not started, you would have seen the fuel pressure dropping off immediately. I am confused, I hope I am not alone
I also have seen a full on returning FPR and i use hose pliers and shut the return down to visually witness the pressure cease to drop off on my gauge.
learning on you tube tnx to all this veteran pelple that dont mind sharing their knowledge,,,,,tnx to all,,,,,,,,,,,,i never knew what was rich or lean conditions till now,,,now i undertand if its too much air or too much gas,,,,,,,,,,,,,,,,,,,,,,,,,
Great information. Wouldn't you see a stuck open fuel pressure regulator watching fuel pressure bleed off or not seeing a pressure rise while snapping the throttle?
Those case studies are great and I wish I could just retain all your teachings. I feel like I need some kind of regulator replaced in my brain. All the info goes in, but some how all the important things leak back out and stupid stuff stays behind. Please do a case study on my head and tell me which part we need to poke to fix it.
Very helpful, same thing happened to my truck got on highway and it jus bogged out and died. Well it’s not the only issue I have right now, the break lights won’t shut off, radio quit working. I got some connection issue I believe.
Bernie ripping around in a hot stick-shift pickup...what a boss! :))) So how is the RAIL pressure different from the pressure at the TRANSDUCER? If all the fuel just went back into the tank due to a faulty regulator, then there is NO WAY you would have 35psi in the rail. This one doesn't make any sense!! We need a scientific explanation, Bernie! At 40:30 you mention "if there is a restriction before the rail..."...what would that restriction be?
Also a quick check for a bad regulator is rest pressure. Did this one hold 40psi? Seems like this truck would be a quick 15 minute diag with a fuel pressure gauge and some needle nose pliers... No scopes or gas analyzers required! 😉
I'm guessing it's an off-brand o2 misreporting rich. When the maf is unplugged it defaults to the pre-engineered fuel table and ignores the o2. The pcm is clearly leaning out the system intentionally. I'm pretty sure those early Nissan pcm's report fuel trims opposite of what they really are, at least they have with my scan tools. We never see o2 voltage unfortunately. Combined with the timing having been messed with (mechanical distributor) and you have a nightmare.
That is amazing content. Thanks for posting all these videos. One thing I can't get my head around is why the car was able to correct the injectors pulse when in VE mode (maf disconnected). If there was no air flow issue with the car , the MaF model and VE model should be coming up with the same air mass thus the same injector open time.
Imagine you were the writer of the program- in a case where the MAF fails, you would want to never go lean. I think the strategy would be to use throttle position, MAP sensors, etc, to insure enough fuel was dumped in.
Is it possible to mount fuel pressure gage to measure return line and on that way figure out problem? Indeed on both, then difference in pressure or flow rate have to show us...
Just started watching - but I am thinking some plugged fuel injectors ? Possible bad fuel pump not delivering proper quantity or simply a very dirty fuel filter ?
i wish i knew the right way to learn, like REALLY learn, how to read waveforms and know what all of them mean. this wave form indicates this, that means that. i wish i knew where bernie learned the basics of it all so i could learn from experience after that. i need to know when a valve is opening too late and be able to tell on a wave form. how the heck do i learn this. thanks for the video bernie
Now that's a scan tool and more impressive is Now that's a master mechanic. sure wish I could find somebody like that in houston. my sentra P0171 has kicked my A** and still no fix.
I have the same Nissan and I have exactly the same problem I hope and after all the time I have invested, changing the fuel pressure regulator it will improve. Thanks you Sr.
ok i'm still confused on how you can have pressure, but that much return. there would have to be a restriction after the guage tap point and before the rail, unless the regulator is not at the end of the rail but in parallel with it. even then there's gotta be a restriction
Agree, we are missing some data. I've seen a pulse dampner do this on a Toyota or maybe a Nissan?? Years ago. It had good fuel psi between the filter and rail, but not in the rail. Can't remember though if it was return type of not. But I looked at this design and i don't see one!! Regulator is last in line and there is no way I can see fuel psi measuring good before the rail, but low in the rail. It's just not physically possible. But Bernie is a super genius, so maybe I'm missing something. It would have been helpful to see those fuel pressure connections and the rail itself. Something is missing here.
There is data which was briefly mentioned, but I thought highly important. In the beginning he mentions low vacuum, late ignition timing will cause that. Plausible previous parts changers set it by ear completely screwing the base timing the pcm needs. Although we see fuel trims, we never see upstream o2 voltage. We do see the pcm shortening the pulse width when the maf is plugged in. When the maf is unplugged, the pcm defaults to the pre-engineered fuel table and the truck runs okay. His transducer is reading down into the 37-ish psi area and specs call for 43psi (pressure regulator replacement completely justified) Opinion: This model was shortly after the obdii requirements, and Nissan did not adapt fast or in full compliance. From experience, the fuel trims read opposite of what they actually are. Although you can clear codes via a scan tool, there is a separate procedure for a relearn (not the proper word) on those Nissan pcm's that involves a screwdriver turning a recessed knob directly on the pcm with a LED turning green/red (I don't remember the exact procedure) which needs to be done even when installing a new o2 sensor. I think what we're missing is that when the MAF is unplugged, the pcm not only ignores that, but it also ignores the o2. It's running on pre calculated fuel tables. I think the o2 was likely showing a rich condition. If memory serves me, this is one of those vehicles where only the OE or OE manufacturer (Bosch for this) will read correctly. If the wrong o2 sensor is installed on the truck, this would make sense to me why the truck is showing lean on his analyzer and matching the injector pulse width. Fire the parts cannon with multiple sensors that all need that relearn procedure, base timing is way off, the situation is even worse.
@@ScannerDanner can"t wait for the answer. I like the way Bernie lets the dramatic tension build up before he weighs in. There could still be a restriction in any line between the gauge T point and the rail, theoretically at least, a clogged rail, though never seen a clogged rail to the extent necessary. Low vacuum, mentioned at the beginning, would cause a higher than spec pressure in the rail? Common Bernie, tell us the secret!!
@@dwasse6167: NICE POST. 1. Fuel pressure with NEW regulator 35-36psi vs 37psi original 😆. 2. Scanner indicated "LEAN" & "RICH" in sync with the gas analyzer and performance, so I'm inclined to believe PCM knew it was lean. Notice at end the LTFT finally started helping, and TOTAL fuel trim up to +30%, and injectors' at 3mS -- that's why it's idling. If MECHANICAL fuel supply problem is so bad that truck cannot idle, then it cannot pop up to 7% CO and ~1450 PPM HC just by unplug MAF 😆, and certainly cannot road test. I wish Scanner Danner there to do a WOT pull so we could see O2 indicator in OL with call for power.
Hi there, thank you for the video. I have been chasing an issue on my 96 that’s not nearly as bad of an idiot as this little red one but my idle will occasionally stumble and in some cases die will happen when I push the clutch in sometimes as well it will just fall on its face but cranks right back up. I ran the tests on my fuel output which is good snd aeration and fuel sample tests both good. Went to return side of regulator and got just as much fuel as the supply side like you showed here. Ordered one and hoping it helps or it’s back to chasing the unhappy sensor or control valve. Oh how I prefer a basic carburetor…
Although Bernie is the best, I kind of feel we have been misled. He said the pressure regulator was the fault, well as it is actually controls pressure how comes the pressure transducer read correct psi? I think a old analogue gauge would of been more accurate. But still he is a genius.
Pressure was 35-36psi at END of video; with "NEW" regulator. It was 37psi during troubleshooting 😆. Fuel regulator on opposite side of from fuel inlet (as most are), and BT demonstrated that no restrictions BEFORE regulator. You are not crazy to think something is fishy about conclusion. We're told that a mechanical fuel supply issue caused it not to idle, but it jumped to 7% CO & ~1450 PPM HC with MAF unplugged 😆. Funny. At end, total trim +30%; LTFT finally came around and increased TOTAL trim, which got injector pulse up to 3mS -- that's why it was finally idling. Trims, O2 indicator and exhaust analyzer readings interesting during video. This is a great case study. I will watch again when i have time.
Does someone have enough technical knowledge to explain why the Nissan's injector waveforms had, what appears to be, a mini sine-wave after the towers? Based on my knowledge, it would suggest that there is some type of capacitance in the circuit, as circuits with both inductance and capacitance will oscillate like this.
if there was an initial good fuel pressure reading and if the regulator is bypassing that much fuel, the fuel pressure should be low because the regulator is the restriction that creates a rise in fuel pressure as long as the pump is working correctly. Not sure how you can still read good fuel pressure. You said the fuel pressure was hooked up between the fuel filter and rail, so if the regulator is bypassing that much fuel I can't see why there is a normal fuel pressure reading? Something is still not adding up here.
I agree something isn't right,, The only way it can be doing that is that the fuel regulator is returning fuel before it gets to the injectors would have been nice to know what type of system and seen the connectors,, or just crimp off the return line and see what happens
Great lesson . I wonder if the shops who fired the parts cannon are going to take the blast ? Or do they pull out the list of 100 excuses ? Does their sign STILL read EXPERT Auto Repair ? Change it to EXPENSIVE AUTO Repair !
1st problem that vintage Nissan doesn't like aftermarket parts. 2nd problem is that vintage Nissan had injector problems. We used a wet cell injector. Which means the windings of the coil were submerged in gasoline. all the people that use cheap gas had injector problems . We really didn't have any issues with mass air . So at what point do you stop fixing what other people screw up. And start fixing the real Concern with the car.
Nissan Juke 1.6 advice appreciated No fault codes on diagnostic . Drive above 50 mph with acceleration bring a abs and traction skid light on. And brakes applied itself. On live data while driving readings don't look correct on ABS pump solenoids. Sensors have no changes in readings. Can you help please
I don't understand why unplugging the MAF made it run better with fuel pressure at the rail being low. I understand different fueling strategies but why don't the different strategies match each other better. MAP sensor bad too? - not with Bernie checking it.
The MAF reads the air going across it and the computer calculates how much fuel to deliver. When the MAF gets unplugged the computer starts looking at the engine vacuum in this case and uses a different fuel map table. He showed the on times of the injectors and with the MAF unplugged the fuel injectors had a longer pulse and in that case the injectors sprayed more fuel and the engine ran better. I hope this makes sense.
It no longer knew what the airflow was so it could not use primary strategy (know air flow needs knows fuel amount) it had to rely on secondary feedback systems to adjust how much fuel it provided which in this case was better at providing enough fuel
@@troutjunkie7330 I see what you mean, unplugging MAF made the computer change to a different algorithm - but fuel pressure never changed so how can you get an improvement.
@@kandkob The injectors are still flowing but not at the correct rate. When the MAF was unplugged the PCM added more injector on time which equals more fuel entering the combustion chamber
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once every couple generations, a man comes along that revolutionizes an industry and ALSO has a passion to teach it to everyone eager enough to learn it and listen to it. Mr. thompson you are a gift
or this guy is nuts
@@111-c7x2t genius is commonly mistaken for eccentricity
45 Minutes of i Life i could not have spent better.....Thank you for these great Case Studys !
Second
Also it's a good day when Bernie posts a video!
It's great to see you're so enthusiastic about the car. It really shows your love for diagnosing vehicles. Glad you had fun on this .
You just know the car’s gonna get fixed when Bernie shows up!
Ironically I don't think this truck is fixed 😅 wish Bernie would respond to the comments!
So thankful Bernie is willing to share these case studies. So many gems
Very interesting, big thanks! "Volvo Laplander Camper"
I watch his videos a lot. I feel like the man is playing chess, while I’m trying to color inside the lines with my crayons
Brilliant Bernie as always. Really look forward to your teaching videos. Wish my school teachers had been this enthusiastic when i was at school.
Always get excited when I see a new video from Bernie. Always very interesting and learn a lot
Once you know it's fuel
Delivery first thing I do is pinch the rubber return line to the gas tank and watch the data quick way to check the regulator
Holds the volume in the fuel rail 👍
You sir will be jot down in history as a diagnosis legend.
Man i love these videos. Bernie has such passion for thinking through problems to find the fix. Amazing!
Anyone who doesnt believe in using scopes is doomed
Hi Bernie great video. I I'm alittle confused with some of the other people in the comments about the fuel pressure reading showing good with a bad regulator. Thanks for the awesome video as always..SAVAGE
Fuel pressure at the rail is good, but the regulator is letting it bypass it afterwards and return to the tank instead of keep pressure on the injectors
Thank you for another valuable lesson Mr.Thompson !
Excellent coverage loved the extra voltage to amp info. I had to watch this twice to absorb the info. Awesome stuff
Dang.. I got stuck on a similar red 4 cylinder nissan truck... and changed the throttle body with no success. Great video. Won't miss this again.
Thank you so much, you’re very appreciated in this community.
We Used an EGA back in the early 80s in high school for diag and tuning. Super useful tool!
Wow. What a rabbit hole BUT logic and data wins again! Extremely educational. Thanks for showing us. Peace
Bernie your videos are just a must watch your skill level is just another level.
Wow, I love this guy, deep in the deets, which I will be using to hopefully fix same problem with 86.5-V6D21
Thank you
Like always, enjoying and learning a lot with you, Mr. Bernie, everything its very useful from your videos, hope you have a great day
Great diagnostic and thought process , thanks for sharing
I have a 1991that I brought brand new, when last year injector #3 shorted and went to "technicians" who did not know how to analyze this primitive OBD 1 fuel injection system, and ended up doing it myself, buying only OEM sensors, as process of elimination. I swear I will never trust OBD2 technicians who do not show remorse, charging high prices, plus mark-up for counterfeit Chinese injectors, and sensors. I spent about $1,500 and swapped those sensors, all of them OEM which included ECM. MAF, TEMP, IAC, TPS, AIR TEMP, AND OXYGEN. I even had those new injectors tested, from a shop in Torrance, California who gave me a detailed report of the performance of each injector, and with my confidence boosted I passed emissions with flying colors. I am new to your channel and I am subscribing, I only whish I did before going to the scum bag "technicians" who only ripped me off.
A very valuable lesson. Specially the reading of the bottom of the injector voltage. Awsome
great job mr. Thompson. I love the way you break down the diagnostics.
Big fan of your channel.
Moral of story is, it takes 8k worth of equipment these days to fix 800 dollar truck, plus price of time invested in acquiring the knowledge on how to.
My 2 cents
Go figure ...
great car, very interesting case. learned a lot and enjoyed it very much, thank you!
Guys I hope this helps, famous last words on stuff that makes perfect sense. Awesome
First of all mad props to Mr. Thompson for his excellent diagnostic routine. My Issue I have with the FPR (Fuel Pressure Regulator) being at fault is this: The Fuel Pressure was being monitored by a pressure transducer into the scope, if the FRP was just full on returning at pump rate, then when the key was switched on and engine not started, you would have seen the fuel pressure dropping off immediately. I am confused, I hope I am not alone
I also have seen a full on returning FPR and i use hose pliers and shut the return down to visually witness the pressure cease to drop off on my gauge.
Excellent Video ! Love learning , Can't get enough Thanks Bernie !
Always enjoy your videos Bernie.
Very good video enjoyed it gotta learn how to read scan tool freeze frame data
learning on you tube tnx to all this veteran pelple that dont mind sharing their knowledge,,,,,tnx to all,,,,,,,,,,,,i never knew what was rich or lean conditions till now,,,now i undertand if its too much air or too much gas,,,,,,,,,,,,,,,,,,,,,,,,,
Thanks Bernie your lessons are always interesting, thanks for share.
Great video Bernie i learned lot of stuff from you thank you so much.
Great information. Wouldn't you see a stuck open fuel pressure regulator watching fuel pressure bleed off or not seeing a pressure rise while snapping the throttle?
Yup. I question the annunciated fuel pressure. It it measured upstream of an orifice?
Excellent case study Bernie. Thanks!
Those case studies are great and I wish I could just retain all your teachings. I feel like I need some kind of regulator replaced in my brain. All the info goes in, but some how all the important things leak back out and stupid stuff stays behind.
Please do a case study on my head and tell me which part we need to poke to fix it.
Very helpful, same thing happened to my truck got on highway and it jus bogged out and died. Well it’s not the only issue I have right now, the break lights won’t shut off, radio quit working. I got some connection issue I believe.
Bernie ripping around in a hot stick-shift pickup...what a boss! :)))
So how is the RAIL pressure different from the pressure at the TRANSDUCER? If all the fuel just went back into the tank due to a faulty regulator, then there is NO WAY you would have 35psi in the rail. This one doesn't make any sense!! We need a scientific explanation, Bernie! At 40:30 you mention "if there is a restriction before the rail..."...what would that restriction be?
I guess the hoses between the transducer and the fat rail could account for most of the pressure drop... Man this one messed with my head lol
Also a quick check for a bad regulator is rest pressure. Did this one hold 40psi? Seems like this truck would be a quick 15 minute diag with a fuel pressure gauge and some needle nose pliers... No scopes or gas analyzers required! 😉
He's keeping it "impressive", not "easy".
Nice point though!
@@PineHollowAutoDiagnostics for real huh that would have been one of my test for sure but how did it run better with the mass air unhooked?
I'm guessing it's an off-brand o2 misreporting rich. When the maf is unplugged it defaults to the pre-engineered fuel table and ignores the o2. The pcm is clearly leaning out the system intentionally. I'm pretty sure those early Nissan pcm's report fuel trims opposite of what they really are, at least they have with my scan tools. We never see o2 voltage unfortunately. Combined with the timing having been messed with (mechanical distributor) and you have a nightmare.
That is amazing content. Thanks for posting all these videos. One thing I can't get my head around is why the car was able to correct the injectors pulse when in VE mode (maf disconnected). If there was no air flow issue with the car , the MaF model and VE model should be coming up with the same air mass thus the same injector open time.
Imagine you were the writer of the program- in a case where the MAF fails, you would want to never go lean. I think the strategy would be to use throttle position, MAP sensors, etc, to insure enough fuel was dumped in.
Is it possible to mount fuel pressure gage to measure return line and on that way figure out problem? Indeed on both, then difference in pressure or flow rate have to show us...
Awesome work as always Bernie.
Just started watching - but I am thinking some plugged fuel injectors ? Possible bad fuel pump not delivering proper quantity or simply a very dirty fuel filter ?
Dr. Thompson fixed it again!
i wish i knew the right way to learn, like REALLY learn, how to read waveforms and know what all of them mean. this wave form indicates this, that means that. i wish i knew where bernie learned the basics of it all so i could learn from experience after that. i need to know when a valve is opening too late and be able to tell on a wave form. how the heck do i learn this. thanks for the video bernie
Amazing lecture!
I really appreciate the information, thank u sir
THE BEST Great Vid as Always Thanks so Much for Sharing
I like gas analyzers too
Now that's a scan tool and more impressive is Now that's a master mechanic. sure wish I could find somebody like that in houston. my sentra P0171 has kicked my A** and still no fix.
Thank ypu for sharing your knowledge and experience
Great stuff once again Bernie!
Hi, where is your shop located. This is very informative and I would like my Volvo Car with air-fuel issues diagnosed. Thank you.
Wow, this one would hurt a lot of people.
Another killer video Bernie.
A $22.OO PART...VS ALL THE MAN HRS AND PARTS SLINGING...WOW...Good Job Bernie
Very good video. Greetings and a big hug from Chile!!!! ;)
Very nice explanation, thanks for you teachings, Teacher
Bernie, your looking real tired, take a break. Well understand you being away.
Great work once again
I have the same Nissan and I have exactly the same problem I hope and after all the time I have invested, changing the fuel pressure regulator it will improve. Thanks you Sr.
Fixed?
Was it fixed
Thanks Bernie. great video so muck info
ok i'm still confused on how you can have pressure, but that much return. there would have to be a restriction after the guage tap point and before the rail, unless the regulator is not at the end of the rail but in parallel with it. even then there's gotta be a restriction
Agree, we are missing some data. I've seen a pulse dampner do this on a Toyota or maybe a Nissan?? Years ago. It had good fuel psi between the filter and rail, but not in the rail. Can't remember though if it was return type of not. But I looked at this design and i don't see one!! Regulator is last in line and there is no way I can see fuel psi measuring good before the rail, but low in the rail. It's just not physically possible. But Bernie is a super genius, so maybe I'm missing something. It would have been helpful to see those fuel pressure connections and the rail itself. Something is missing here.
Can Bernie do a follow up on this dilemma….
There is data which was briefly mentioned, but I thought highly important. In the beginning he mentions low vacuum, late ignition timing will cause that. Plausible previous parts changers set it by ear completely screwing the base timing the pcm needs.
Although we see fuel trims, we never see upstream o2 voltage. We do see the pcm shortening the pulse width when the maf is plugged in. When the maf is unplugged, the pcm defaults to the pre-engineered fuel table and the truck runs okay. His transducer is reading down into the 37-ish psi area and specs call for 43psi (pressure regulator replacement completely justified)
Opinion: This model was shortly after the obdii requirements, and Nissan did not adapt fast or in full compliance. From experience, the fuel trims read opposite of what they actually are. Although you can clear codes via a scan tool, there is a separate procedure for a relearn (not the proper word) on those Nissan pcm's that involves a screwdriver turning a recessed knob directly on the pcm with a LED turning green/red (I don't remember the exact procedure) which needs to be done even when installing a new o2 sensor.
I think what we're missing is that when the MAF is unplugged, the pcm not only ignores that, but it also ignores the o2. It's running on pre calculated fuel tables. I think the o2 was likely showing a rich condition.
If memory serves me, this is one of those vehicles where only the OE or OE manufacturer (Bosch for this) will read correctly. If the wrong o2 sensor is installed on the truck, this would make sense to me why the truck is showing lean on his analyzer and matching the injector pulse width.
Fire the parts cannon with multiple sensors that all need that relearn procedure, base timing is way off, the situation is even worse.
@@ScannerDanner can"t wait for the answer. I like the way Bernie lets the dramatic tension build up before he weighs in. There could still be a restriction in any line between the gauge T point and the rail, theoretically at least, a clogged rail, though never seen a clogged rail to the extent necessary. Low vacuum, mentioned at the beginning, would cause a higher than spec pressure in the rail? Common Bernie, tell us the secret!!
@@dwasse6167: NICE POST. 1. Fuel pressure with NEW regulator 35-36psi vs 37psi original 😆. 2. Scanner indicated "LEAN" & "RICH" in sync with the gas analyzer and performance, so I'm inclined to believe PCM knew it was lean. Notice at end the LTFT finally started helping, and TOTAL fuel trim up to +30%, and injectors' at 3mS -- that's why it's idling. If MECHANICAL fuel supply problem is so bad that truck cannot idle, then it cannot pop up to 7% CO and ~1450 PPM HC just by unplug MAF 😆, and certainly cannot road test. I wish Scanner Danner there to do a WOT pull so we could see O2 indicator in OL with call for power.
Hi there, thank you for the video. I have been chasing an issue on my 96 that’s not nearly as bad of an idiot as this little red one but my idle will occasionally stumble and in some cases die will happen when I push the clutch in sometimes as well it will just fall on its face but cranks right back up. I ran the tests on my fuel output which is good snd aeration and fuel sample tests both good. Went to return side of regulator and got just as much fuel as the supply side like you showed here. Ordered one and hoping it helps or it’s back to chasing the unhappy sensor or control valve. Oh how I prefer a basic carburetor…
Haha that should say not nearly as bad of an idle as the red one was before replacing fuel pressure reg.
Great job and video like always
awesome, Bernie.
Although Bernie is the best, I kind of feel we have been misled. He said the pressure regulator was the fault, well as it is actually controls pressure how comes the pressure transducer read correct psi? I think a old analogue gauge would of been more accurate. But still he is a genius.
Pressure was 35-36psi at END of video; with "NEW" regulator. It was 37psi during troubleshooting 😆. Fuel regulator on opposite side of from fuel inlet (as most are), and BT demonstrated that no restrictions BEFORE regulator. You are not crazy to think something is fishy about conclusion. We're told that a mechanical fuel supply issue caused it not to idle, but it jumped to 7% CO & ~1450 PPM HC with MAF unplugged 😆. Funny. At end, total trim +30%; LTFT finally came around and increased TOTAL trim, which got injector pulse up to 3mS -- that's why it was finally idling. Trims, O2 indicator and exhaust analyzer readings interesting during video. This is a great case study. I will watch again when i have time.
Does someone have enough technical knowledge to explain why the Nissan's injector waveforms had, what appears to be, a mini sine-wave after the towers? Based on my knowledge, it would suggest that there is some type of capacitance in the circuit, as circuits with both inductance and capacitance will oscillate like this.
Simply the best !
Why would the fuel pressure reading be "ok-ish" when the fuel pressure regulator is leaking ?
FANTASTIC!
if there was an initial good fuel pressure reading and if the regulator is bypassing that much fuel, the fuel pressure should be low because the regulator is the restriction that creates a rise in fuel pressure as long as the pump is working correctly. Not sure how you can still read good fuel pressure. You said the fuel pressure was hooked up between the fuel filter and rail, so if the regulator is bypassing that much fuel I can't see why there is a normal fuel pressure reading? Something is still not adding up here.
I agree something isn't right,, The only way it can be doing that is that the fuel regulator is returning fuel before it gets to the injectors would have been nice to know what type of system and seen the connectors,, or just crimp off the return line and see what happens
You kick ass Bernie 🤘
Did anybody else notice the eye in his lecture lol creepy i had to cover it with my finger 😅 thx bernie for the knowledge
This guy’s a genius,but we all knew that…
That's pure experience !!!!!!!
Hi. My 1994 d21 nissan truck idling rough but won't die and lose power.
Great lesson . I wonder if the shops who fired the parts cannon are going to take the blast ? Or do they pull out the list of 100 excuses ? Does their sign STILL read EXPERT Auto Repair ? Change it to EXPENSIVE AUTO Repair !
You too will be successful all’s you need is a scope and a Bernie Thompson!
I would say that over the years I've attended at least 50 classes in person with Bernie. Between him and JT it made me into the tech I am today
Now I know about your
Secret weapon
Bernie Thompson 👃✌
Thanks Barni
Bernie is the GOAT
1st problem that vintage Nissan doesn't like aftermarket parts. 2nd problem is that vintage Nissan had injector problems. We used a wet cell injector. Which means the windings of the coil were submerged in gasoline. all the people that use cheap gas had injector problems . We really didn't have any issues with mass air . So at what point do you stop fixing what other people screw up. And start fixing the real Concern with the car.
Damn someone loaded the parts cannon and went crazy I know that was expensive
thanks, from peru
With Bernie on the job, the fix is in!
Nissan Juke 1.6 advice appreciated No fault codes on diagnostic . Drive above 50 mph with acceleration bring a abs and traction skid light on. And brakes applied itself. On live data while driving readings don't look correct on ABS pump solenoids. Sensors have no changes in readings. Can you help please
I’ve had this issue before. Under ABS module, Calibrate steering angle sensor and calibrate G sensor.
I don't understand why unplugging the MAF made it run better with fuel pressure at the rail being low. I understand different fueling strategies but why don't the different strategies match each other better. MAP sensor bad too? - not with Bernie checking it.
Thank you
Great stuff thanks.
Can that computer tell you about what’s going on with the transmission
O scope elite 8 e tradução português Brasil ?
Professor I utilize propane enrichment while scoping Ho2S.Quick like 5 minutes
I really enjoyed it too!!!
Amazing how knowledgeable you are
So it was the regulator? but why unplugging the MAF worked?
Exactly. It went from lean to rich by unplugging maf. How is that possible with no fuel pressure at the rail due to regulator.
The MAF reads the air going across it and the computer calculates how much fuel to deliver. When the MAF gets unplugged the computer starts looking at the engine vacuum in this case and uses a different fuel map table. He showed the on times of the injectors and with the MAF unplugged the fuel injectors had a longer pulse and in that case the injectors sprayed more fuel and the engine ran better. I hope this makes sense.
It no longer knew what the airflow was so it could not use primary strategy (know air flow needs knows fuel amount) it had to rely on secondary feedback systems to adjust how much fuel it provided which in this case was better at providing enough fuel
@@troutjunkie7330 I see what you mean, unplugging MAF made the computer change to a different algorithm - but fuel pressure never changed so how can you get an improvement.
@@kandkob The injectors are still flowing but not at the correct rate. When the MAF was unplugged the PCM added more injector on time which equals more fuel entering the combustion chamber
thanks for video