Testing for a leaking, ruptured, fuel pressure regulator diaphragm
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- Опубліковано 12 вер 2024
- How to verify the cause of an intermittent long crank and a start/stall condition.
Keep in mind as you follow this video that there are differences in fuel system designs. Some fuel pressure regulators are in the fuel tank or are part of the fuel filter. While other systems use a variable speed fuel pump and have no fuel pressure regulator at all.
Symptoms:
- intermittent long or extended cranking
- start/stall condition
- rich exhaust trouble codes (P0172, P0175)
- no start from a flooded condition (severe leak)
- fuel contaminated oil (severe leak)
Fix:
- replace the fuel pressure regulator
- change the engine oil (possible fuel contamination)
Testing procedures shown:
- how to use fuel trim as a guide in finding a leaking fuel pressure regulator
Tools used:
- scanner (Solus Pro)
Related videos:
Leaking Fuel Pressure Regulator (symptoms and testing)
• Leaking Fuel Pressure ...
GM CPI Leak Part 1 (bleed down testing)
• How to identify and re...
GM CPI Leak (part 2) Regulator repair
• How to identify and re...
Playlists:
(Chapters 14, 15,16) Fuel Delivery and Fuel Pressure Testing
• (Chapters 14, 15,16) F...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium www.scannerdan... There is a 14 day free trial.
On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.
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They say a person learns something new everyday. Today, that was me. And I have you to thank. You just saved me a lot of time and money. God bless you
This is a great example. I think many techs would have missed that call. I would expect to see fuel immediately.
These videos are really helpful. Much more so than the grumpy old guys I had in the shop teaching me stuff when they felt like it.
That was THE BEST - ABSOLUTE BEST - TESTING VIDEO I've ever seen so far. You actually showed the damn failure. I already tested it according to what I read online and I didn't wait. Thanks for the excellent test tutorial.
Thanks so much! I'm glad this helped you
Thank you for replying so quick 👍. This is a fuel return to the fuel tank port injected setup system.The fuel regulator required vacuum from the intake manifold and it is installed right after the fuel rail. Do you know how to test a fuel regulator before it is install on any car. with a vacuum pump ?
ScannerDanner your video just saved a Canadian working man some time, effort and money. You are the man, ScannerDanner! Good on ya!
Graeme Berke
Just wanted to say a huge thank you for the video. I have been fighting a stall/hard start problem for months. A mechanic I asked, told me he was sure it WASN"T the FPR cause he has never had to change one. So I threw several other parts at it. Nothing. Even sucked on the regulator to check for gas. Once I ran the car without the vacuum line, seven seconds and it started spewing fuel! Great job!!!
Wow Paul, even these OLD videos are great. I would never have waited that long if I hadn't see this.
I've had cranking and idling problems just as explained in your video and sure enough fuel sprays from my regulator once the house is pulled... Glad to see it was a simple as this. Great explanation too, along with your other videos. Keep em coming!
dude, you have no idea how much pain ive been through. i got a 1988 chrysler dynasty, and it was having a hard time starting without me putting the gas pedal to the floor. i replaced just about every sensor i could, i checked my pressure (obviously not long enough) and only once i removed half my manifold did i realize my fuel pressure regulatore is completely buggered. THANK YOU MAN THIS IS STILL SO HELPFUL!!!!
awesome, glad it helped you!
Man I've been learning a quite bit from you I tell ya. love how you get straight to the point. Keep up the great work. 👍
What is your fuel pressure? Also these 3.1 engines are known for intake gaskets leaking coolant into the engine, this could contaminate your O2 sensor and cause a false rich condition and negative fuel trim numbers.
U are a hero to fix ur own car guys, I'd never think to wait, bless u good sir.
Thank you someone who actually tested this problem. Best video out there plain simple. Thanks again
Thanks brother
Thanks for another great video..You and Eric The Car Guy are my 2 main go-to guys online..Thank you for your comprehensive instructional videos..They've taught me so much when I needed it most..God bless!!
Excellent. Looking for a lack of fuel pressure and found this. Pressure reg was leaky, and was having intermittent long crank times. Didn't know how to describe this problem or how to go about diagnosing it. Thanks so much for this. Now onto the main issue - low fuel pressure.
DUDE, your video just helped me out so much. I just walked out to my car and tried the fuel regulator check and that was my hard start problem. ordered a regulator today. thanks alot your great.
after waching many of your videos i find a problem very fast in a nissan frontier 2006 that had a rough idle with up and down rpm, and i thought it was a vacuum leak, but after checking the data with the scanner the fuel trim numbers were negative in every rpm, my iac was not causing the up and downs, it was the injection pulse that was causing the up and downs, and also long crank time, and the first thing i did was to check for a ruptured in the fuel regulator and it was leaking very bad, 20 times worse than the one in this video, thank you so much, you are the best
MY GOD! WHAT A LEGEND IMA GO TEST MY 01 crv can’t wait. It has poor acceleration and I think it’s this part hopefully not the fuel pump
, this videos helped me resolve the issue of hard crank when warm, the old broken regulator would flood my vacuum lines. i watched your video after many failed attempts to resolve it otherwise and was able to fix it finally after this video one it. love you much.
nice job! you are clearly functional (and I mean that with the utmost respect)
With those numbers, what this tells us is you DO NOT have a fuel delivery problem and that your MAF sensor is clean. So what I am getting at is do not change the fuel pump and expect this thing to have more power. It will not. You may fix your bleed down issue and long crank time but NOT the low power issue. As I suspected, you have two problems, what does the customer want fixed? long crank time or low power?
Wow...this was really helpful. Patience is so important when it come to diagnosing mechanical problems. Thanks for this video.
I KEPT PULLING HOSE OFF, NEVER SAW FUEL. I AM NOW GOING TO INSTALL THE NEW FPR. THANK YOU!
I used this technique to solve a rough idle/stall complaint in about 5 minutes the other day that multiple other technicians couldn't find. And its all thanks to scannerdanner!
sounds like a lean condition. the reason it is possibly running better is when you disconnect the regulator vacuum hose you are increasing fuel psi by as much as 10 psi.
not sure about the vibrating return line. maybe a pulsator has gone bad?
check it for a vacuum leak
Thanks for the video bro. I have seen not one other video that has stated to give the regulator time to see if it will leak. They all say pull vacuum hose off and if you dont see fuel, put it back on. Props to you man!
@ScannerDanner BTW a slightly leaking regulator will cause starting problems and poor low RPM performance, but will run completely normal under loads. Engines can handle more fuel under load without any noticeable driveability problems.
I wish I had seen your video before the regulator went bad in my 97' Olds LSS with 3.8 engine, could have saved myself some money as I had a shop do the repair. Thanks for the video.
@michobebemckawi That is completely normal on a drive by wire system. It is a default mode that causes that. If the engine is not running the PCM will NOT open the throttle plate in direct proportion to accelerator pedal position.
........excellent , to the point, clearly stated.....best explanation if heard. I appreciate that you put this out here for us.
."i've heard" not if heard.
haha I knew that. You can edit your comment. Just so you know. Thanks again!
My test went for nearly 4-5 minutes. Yep i have a faulty fuel pressure regulator. Just as i thought. Great vid mate. Thanks
I love this channel, ScannerDanner you are the man!
I am working on a vacuum issue and suspect my regulator, but your showing the intensity of that vacuum just now would be good for me to try and demonstrate on my own vehicle. It s a FORD Sporttrack, so you can imagine my frustration. :)
@buddha65281 Any trouble codes? When you say "The start is rough" do you mean a long crank time or when it starts it runs rough for a few minutes? Could be many things: plugs, plug wires, one of the coil packs, clogged exhaust, fuel pressure dropping under load, dirty MAF sensor.....a loose nut behind the wheel :)
that connector is on the inner fender either on the driver side or passenger side. run the key on engine off self test and the key on engine run self test and let me know what you have. keep in mind when you run the key on engine run test that you must have the engine warm first and you must follow your prompts or you will set false trouble codes
@therealgarygnu Nice! Did you have an intermittent long crank time and or start/stall problems?
@KingVee44 double check under the hood that you don't have an external leak, usually you can't smell the fuel if its the regulator diaphragm. It gets pulled into the intake. but if it is really bad I guess you could smell it.
Great video paul .
Patient is; indeed the key
@renchjeep You don't need an expensive scan tool to view fuel trim numbers. And you are correct about the upper rad. hose. It was a little risky shooting this one.
Thank you my friend. And I couldn't agree more, I wanted to stress with this video how long you have to wait sometimes to see fuel come out of these.
@AutoTechHector Two things, does the fuel pump prime when the key is first turned on? If not you may have a FP relay problem. Watch my video on fuel system electrical designs. Second is how fast does fuel pressure build to spec during the long crank problem.
@michobebemckawi Great question! Yes it is normal because on a dead rev. (no load rev in park) it takes very little throttle opening to raise RPM. This is a good observation on your part and will help you understand why the TPS by itself is a poor input for engine load.
No comments? Good tip and video. Close ups are great. Keep up the good work.
@kredmond61 check your fuel pressure when it doesn't start. Ignore the #6 misfire for now it may be related to a fuel issue with your lean code.
Awesome, glad it helped. Keep watching, I have around 54 videos and more to come
Love the comment about Uncle Sam's corrosive fuel LOL
@ScannerDanner I bought a used 95 rover si 214. Took it to my mechanic for a general tune up and oil change and it seems to run smoother. He mentioned a bad hose in the central port fuel injection system! I have no idea about codes because I don't repair cars myself. My limited experience of engines is based on lawnmowers and farming equipment with manual chokes. If you flood the engine either it don't start or it runs very rough. Anyway thanks for the help.
Is it the alcohol that damaged the diaphragm ?
do you speak about the ethanol/gas mixture at the pump?
i'm in Europe i would like to know about it.
@HuskyHiker I don't, I say clean the MAF sensor first. Very common to have cold engine driveability problems with a dirty MAF. Of course this affect warm engine operation too, but cold engine is more pronounced. You could try to start the car with the MAF unplugged and see if this fixes your long crank. If it does, it is definitely dirty.
I have a 2003 chevy avalanche.
For the most part it idles and runs fine, however I've noticed there's a slight stutter in the idle.
No vacuum leaks based off trim numbers.
Just like in your video, there are slight negative fuel trims on the short fuel trim levels, indicating a little rich, i.3 -3.9% however the numbers are always with thin 10 points plus or minus, so in that regard it seems to be within spec and the numbers of pretty good.
They go to zero, then slightly negative, then zero again.
I didnt throw a code, but in torque app, it said two misfires on cylinder 6 history.
It cleared itself though and then said zero in history, which I thought was odd.
I installed a fuel pressure gauge that sits on my rail all the time, like seen on hot rods etc...
When it's pressured up and primed not running, the fuel pressure sits at 50. When the engine is idling, it stays around 50 and does increase a little bit when you rev the engine.
The problem I have found, is I took a break and an hour or two later when I came back, the fuel pressure had dropped down to 0.
I have had the fuel rail out with the injectors exposed whilel pressurized, and I didn't notice or see any fuel injectors leaking.
I disconnected the vacuum line to the fuel pressure regulator, and the fuel pressure jumped up to about 60 like it should, as far as I'm aware.
Can you still have a faulty fuel pressure regulator even if it responds by increasing fuel pressure when you take the vacuum line off?
Thanks
Thank you for the positive feedback!
Great job, my Corolla has been down 2 months, but the wind will be in her old sails soon!!! thank you very much :)
Nice video, I had the same problem on a 2000 monte carlo. It would take some cranking to start and them shake and run rough for a few seconds, but it would only do it when you started it 15-30 minutes after shutting it off hot. Completely cold it would start fine. Only problems once it was started was a slightly rough idle and hesitation when accelerating off idle, like after sitting at a light for a minute.
I'm sorry. I was scrolling through and I tapped too fast and hit dislike. I have nothing against your statement. It was a mistake.
FlyingDelorean1 hi I have the same problem did you fix it? can you tell me what did you do thanks
@@franciscosardinas8149 i have the same problem except mine turned off after driving 50 miles and it wouldn’t turn on between
Thank you so much for this video!! Helped me discover a bad regulator in my Olds Intrigue 3.5L. Was operating horribly for months.
That should be good enough. If you rig up a clear piece of plastic tubing and connect the vacuum line back up, this will increase your chances of catching it. I have seen these only leak with vacuum AND psi.
Chances are though, with no fuel in 5 min. your good.
Oh my God thank you for the tip on waiting for fuel to leak on my fuel regulater been hunting for inturmitin stall for a year and start tall after warm up . 2002 Chevy monticarlo ss 3800 ll regulater fix it. . thank you .
sweet!
This video is most excellent as I have a 96 Lincoln Continental with a 4.6L that I can't even get to start up anymore. When I was able to start it up though, it ran extremely rough and when I would step on the gas pedal the car would stall. I recently tested the fuel pressure on the rail and it was only 10psi. Of course with cycling the key a couple of times, I could get it higher, but the same issue arose when I tired to start it even after pressuring up to 30psi or so. I gld to know that the fuel pressure regulator could have a significant delay until fuel runs out of it, as I never saw gas coming out of mine either, where as in other videos the gas pours out immediately. I just ordered another a FPR and hope that's the fix as I've already tested the whole fuel system minus the injectors, but I'd be extremely surprised if they were clogged or faulty. Anyways, thank you very much for all your videos, but particularly this one!
Did it fix your issue?
@@EliteNK No, unfortunately it did not. I sold that vehicle years ago for next to nothing because of the ongoing issues and now own two Toyotas, a tundra and an fj cruiser, which I have NO problems with whatsoever!
....what's Amazing ScannerDanner is that you are Sooooo Smart about these things........Anytime I go to an Auto Repair subject on UA-cam....and I Hear Your Voice.....I Know the Answer is Going to be Correct and Well Explained......
Thanks so much! Really appreciate your comment
@ScannerDanner Yes, though the stall problems have only become recent. I've been getting horrible fuel mileage too, along with O2 sensor codes and misfires. I pulled the vacuum line off and it leaked, a lot, right away.
@ScannerDanner Thanks for your quick reply. So yes the fuel pump primes just fine.i haven't checked the fuel pressure buliding up during cranking, but will do that next. thanks for your help.
thank you very much! stay tuned for my video lectures that will soon be available.
@GST1974 low power and too rich do not go together, although black smoke is from a rich condition. You need to start checking some basics. Fuel pressure, exhaust back pressure, timing marks on belt/chain. what about trouble codes? Also what year, make model are we dealing with?
if there is a leak it is usually the regulator. -6 or -8 could be enough of an indicator of a leaking reg. but this WILL NOT cause a low power complaint. just long crank times.
Watch my dirty MAF sensor video for the WOT O2 test and also one on a plugged exhaust where I do the same test. I think you have two separate problems. Although a weak pump could be the cause of both a long crank time and low power but NOT negative fuel trim numbers. Also the bleed down is a concern too
While it is bleeding down you need to pinch off the lines like I do in my two part GM CPI Leak videos.
This will at least tell you what is causing the bleed down and potentially the long crank time. The real question is, is this related to the low power condition or not. Test drive it at WOT and watch O2 mv and MAF HZ. O2 should stay over 800 mv and you should hit around 8500HZ at redline. Be careful, just wind out first gear. Let me know
Finally, n easy test that makes sense, thank u
Is this a MAF or MAP engine on this year? I think it has a MAF, I would look at that next. Watch my GM MAF sensor video (2 part) for testing of it. Also you could have a purge valve problem or possible EGR sticking open a little at idle (this would set a code though). There are other causes, check these first.
Awesome Instruction. My sis has same engine and its intermittently not turning over (cranking) but not starting. Im going to check for this
@michobebemckawi In theory yes, however it is not uncommon to see a number lower than 100% at WOT. Also this characteristic wouldn't be any different on a drive by wire.
You are a wizard for this video. Thank you!
@KingVee44 I have never seen a ruptured diaphram cause a backfire. You may want to make sure your plugs and wires are ok. If you have a high resistance wire or an open spark plug this can cause an intake backfire. With fuel running through the reg. vacuum hose the intake backfire was enhanced and caused all of your damage. I just think something else caused your backfire. Also quit messing around with used regulators. These things go bad all the time and you are likely to keep getting bad ones.
I didn't pay $60 at the parts store or a dealership for mine I just got a cheapy $10 on eBay and it worked quite well car ran real nice I think I had a rich exhaust code of some sort of oxygen sensor or Rich exhaust code of some sort if I recall correctly it's been a few years boy that's pumping out pretty good toward the end of the video there good video brother thank you I already knew about it but thank you good video
Ha, never been called funtional before. Thank your for helping me there's plenty else you could be doing I'm sure. Honestly I could not duplicate the lack of power on a test drive. W/the intermit. Long crank I was going to pinch lines last night but I have braided steel. I will look to see if I can find one accessble near top of tank when I go home, I'm at the shop right now. Its a side job. Fyi diagnosed tow in crank no start 10 min ago with info I learnd from ur videos.
@maycor1076 i knew what you meant, thats why I said I agreed with your suggestion. I was just saying that reading some HCs from the nipple of the regulator would not make me comfortable enough to make a call on a bad regulator. I would agree that there should be no HCs in that location, I just want to see liquid there before I condemn it. But I do appreciate your suggestion thank you!
If it's a small leak it makes sense that it would take a while for it to spit out the tube since the gas has to fill up the area on top of the diaphragm first before spilling out.
Thank you for the information. 96 chevy Lumina with 3.1L engine. It would start good cold and start hard after driving it. Did just what you did pulled the vacuum line off the fuel pressure regulator and in 1.5 min gas came out of the regulator. Thank you again. Jitty
Awesome test . My vacuum hole had a slight amount of fuel wetness . But never thought to do this test
I am going to test mine on Nissan Titan.
Omg there’s hope! I though I finally found what was wrong with my Subaru but then when I check it (without waiting) it was fine and was lost again I hope so bad this is the problem. Thank you!
@IROCwarriorAMC88 Most likely not, start with plugs and wires and don't go cheep on the wires. You get what you pay for. Oh and none of those bosch platinum POS plugs either. If this doesn't fix it you may have a coil pack breaking down or even possible shorted injectors (very common on this model) I have two videos on shorted Multec 1 injectors (same as in your camaro) check them out
you are very welcome, I am glad it helped
Good video!!
Thanks!
He brought me the car for both problems not major concerns just trying to catch a problem before he's stranded. I would like to chase this extended crank 1st. I think this is most important. But I am open to anything I need to do for a solution to either I appreciate the help and experience.
scannerdanner is the manner! Fixed my own car $104, new pressure regulator, woo-hoo
Are u in NJ??? I need help with mine
@maycor1076 agree with your test however I want to see liquid fuel not just HC gases to condemn a fuel pressure regulator that is causing a long crank time.
good tip...gonna recheck my regulator tmrw...if nothing still then injectors
Thanks so much for this video. My friend has a 2000 Chevy Venture and it idles fine but when you go to give it gas, it bogs and spits and sputters... let off and it idles fine again. The start is rough, the fuel pressure is around 50psi. the book calls for 41-47.... Still lost and we are in Germany... So, again. . Thanks! I will check this in just a few! cool!!!!
Sometimes you can rev the motor up to and it'll pump out if it's bad gasoline will pump out of the vacuum nipple on the regulator side.
Man this really help me to see if mine is bad. I have a 2001 Buick Century Custom. My uncle was sure enough to think it is the Fuel Pressure Regulator due to the hard start & rough idle. I pulled the line off it gives the suck pressure but was not long maybe 10 seconds it poured out. Mine is at the top yours to the side. I said that's it. Thanks allot.
Great video. Thank you!
Thanks for the video brother ✌️✌️
All these comments are from years ago 😂 I wonder if the youtuber still checks 😂. Just wanted to throw it out there... great video. And yes a bad regulator can throw you misfire codes. Check the regulator first and foremost.
Of course! I read every comment 😉
ScannerDanner awesome. Subscribed. I have a question, what if the vacuum hose is not working? It’s not sucking any air.
Some systems used a solenoid to control the vacuum. What year make model and engine?
@KingVee44 I understand why you did it. I wasn't trying to be a smart ass, sorry If it sounded that way. I try to fix everything I have for as cheep as possible too.
Well, I don't have enough experience in the field to tell. I'm gonna investigate that. I don't see anything change on the scan data besides the rpm so I'm not sure. Hey I pinched the lines near the tank and I got a bleed down. I took off the upper intake and found leaky regulator. Fuel trims 1 and -1. Fires right up everytime. That's a fix. Thank you
oh man very usefull video, thanks best regards from Venezuela
i have negative short term ft and good long term when starting starts fine but stinks of fuel for few seconds o2 sensors work great tested fpr and was fine only tested few seconds will test again properly
Glad it helped. thank you
Outstanding diagnose video. I have a 85 nissan 300zx that I keep getting fuel regulator codes for and no where in my manuals does it tell me to do this kind of a check. I will check it today but still have my doubts that's where the 2400rpm chocking problem is coming from. Thanks and keep up the good work.
my son has an 86 300zx we just picked up from Florida last year :-)
Mr ScannerDanner
How do you test the FPR on a returnless fuel system? When I pull the back seat out to reveal the fuel pump there are two hoses connected to it. One hose is the fuel outlet, I suppose the other is connecting to the FPR from inside the pump assembly? Please confirm.
Thanks in advance!
You can't. The second hose you see is a vapor line if it is returnless. Unless of course it is a system that puts the reg. in the fuel filter. This is easy to ID by the number of lines on the filter. If it is just two lines, then the reg is in the tank
@ScannerDanner
Are you serious!? That's Great!! I was going to do voltage monitoring for the pedal accelerator sensor to be sure.. they're not as easy to prob as on american cars because of the connectors design and it would've fastidious! Thank you very much sir!
Hell yeah dude. I'm thinking more specifically either the Suth Side or West End?
I did, check out my videos on a GM CPI fuel injection system. there is a part 1 and part 2
Is it a MAP or MAF engine?