Fuel Pressure Regulator Diagnosis + Understanding (HD!!) 

8 years later we are all still benefitting from your video...thanks!

I've been a mechanic for 35 or 40 years he's the only man that could explain to me why a fuel pressure regulator should be behind the fuel rail I always thought all my life the pressure regulator should be in front of the fuel rail thank you sir you are absolutely brilliant!

I know this is an older video but not only did it help me understand a FPR better but the entire process involving fuel travel in a vehicle. This helps troubleshooting tremendously.

I salute you for the ability to explain things. Thank you!

I knew all of this but, your explanations are so much better than mine that I often tell my customers to go home and watch your channel. They usually return as experts on the particular problem with their vehicle. It is fun to have them tell me how to repair their own car. Thanks man. An informed customer is a happy customer.

This was an impressive presentation all round. Video, rate of speaking, clarity, emphasis on key points, and logical steps could not have been better. In fact, as a retired automotive trades instructor I felt a bit jealous. So well done in every sense of the word! Cheers!

I am not a mechanic professional, but I love to listen to your lectures without any need..

First off, I want to thank you for the taking the extensive time to explain this. I happen to bump into your video trying to diagnose an issue with my idle. You have made me a little bit smarter today. Thank you.

Hey Matt, you've made a huge impact on my understanding and overall approach in the past few months. Starting to feel way more confident in my diagnostic capabilities.

As a former high school auto shop teacher, before the advent of fuel injection, I deeply appreciate you video. I tried to instill in my students that knowing how something works you can better determine what is wrong and fix the problem at it's source. Thank you very much for this video.

Great Video Matt! I have been working on cars and motorcycles for years and have taken automotive coursework, your videos certainly meet the mark. You have an ability to communicate the technical in a way that makes it easy to apply in the real world. My favorite is diagnosing fuel trims! Anyone who watches and waits just to call you on a mistake or slight error in communication obviously doesn't understand the purpose of your channel. Please keep em coming!

I don't know how your channel came up on my feed, but, I am thankful that it did, Thanks again for another great video.

Your videos are longs, but they worth gold every minute of it, knowledge is what make a man wise, thanks for sharing your videos, i being having a rich, and have change all the sensors you can think, and maybe this is where my problem is.

Hi, thank you so much.. this fixed my problem after I tried everything else. 10 minute job and no cost. My 1990 Foretravel Grand Villa 460 gas pusher had been sitting for some time and I made a 200 mile trip with to working so bad. The diaphragm in the FPR was stuck at the bottom,removing the vac hose made no difference in the rough idle so t sprayed penetrating oil in the vac hole on the unit and applied high vacuum with my pump and it pulled it loose. The engine instantly worked perfect. Without this video I would still I would still be lost. Thank you so much and I will be enjoying my trip back home because of you. :) Gordon Firth, Nova Scotia, Canada.

Very well explained.I'm an RN, but I love to do mechanic DIY to my cars and my family. Good job explaining how the fuel system works.

Great, logical presentation. When I was in school the best teachers (especially math) taught you to think, reason & solve instead of memorize (or follow confusing, lengthy flow charts). As a retired tech (20 years ago) - actually we were still called 'mechanics,' I thank you for bringing me into the 21st century's fully computerized world. When I retired we saw few OBDII systems in private shops, so you really got me back into the analysis mode for which I'm grateful. I'm currently trying to resolve an intermittent problem- the worst kind- on my 4.6L '06 Grand Marquis (old guy's car) throwing trouble codes P0193, P0171 & P0174 while the car runs flawlessly- except for the illuminated check engine light. The pertinent freeze frame data is RFP @ 75.99 psi-which scares me- and LTFT @ 29.7% on both banks. After watching your above video & the 2 on understanding fuel trim, I'm going to retest concentrating on the P0193 which looks like the real problem area. But testing so far- especially after clearing codes and (temporarily) bypassing the pressure regulator- shows everything within normal specs @ idle, 2500 & 1500 rpm's. My inclination is to repeat the disconnected regulator tests, now that I better understand the systems, then block vacuum to the interior accessories & carry on from there. However, since the car runs so well and this being the elusive intermittent riddle, anything you care to contribute would be ever so much appreciated! Would you consider the RFP value dangerous (it's 39-40psi in all tests)?

Thanks for an excellent explanation of the FPR, I now have a much better understanding of how it works. Being a complete novice, I now feel much more confident when discussing this with a professional mechanic. I will have the testing done because my Jeep sometimes has a hard time starting when it sits for a while. Keep up the excellent videos and excellent explanations; they're invaluable to us novices.

Matt, your videos are very intelligently done. Easy to follow and understand. Thank you for sharing all your troubleshooting knowledge. I learned a TON from your fuel trim videos, and now have a much higher understanding of how trims work. Now working to put it all together with more of your videos -Brian

I am a do it yourselfer; and by no means a master mechanic and I think this channel should be a must for any body

for learning opportunities you present I am very thankful and grateful.

Crystal clear explanation,you deserve half million of subscribers more,this channel is Gold . Keep it up with this helpful and interesting channel. Greetings from a Mechanic 👏.

Thanks for explains the operation and function of the fuel pressure regulator .

Thanks for taking the time off your busy day to make such a nice video tutorial on the fuel regulator and the fuel trims.

Your teaching is not for the engineers but normal technician like us all over the world

Once again a flawless job in explaining complicated systems ...amazing !!!

Every tid-bit of this - is stacking mental gold bars, Thank you... you are making a difference.

Thank You Matt 4 takeing the time 2 teach us old-schoolers how 2 better understand how the FPR works with the conjunction of fule and other fule components I myself have a much better understanding now ! now have subscribed 2 your channel so I can learn more ! 😄👍👍👍 thank you again !!!

for me, the best fuel system tutorial on the web ever, easy to understand, great draws and perfect explanation, thank you very much

This guy is an awesome teacher. Looking forward to checking out all of his videos

Excellent explanation of how a fuel regulator works! Thanks and keep up the excellent tutorials!

8YEARS after, and it's always the best corse concerning fuel pressure regulator that i found it in youtube. many thank's

Man... I call you Mat-The-Genius... You know a little about a lot of everything!!!

Thanks for the excellent communication and video!

Theory, then practical followed by a summary. First class! Many thanks.

Excellent Video! Well, as one saying goes.. " You Never Stop Learning".. It's unfortunate for me that after all the years I actually believed the higher idle would create more vacuum at the regulator.. lol.. Thanks for all the great info and video. It's Appreciated!

Love your patience bro, I get it now, love the way you explain things, the hardest thing is to diagnose but when you know how is supposed to work, is walk in the park, thank you bro💪💪💪🇵🇷 wisdom is knowledge, and to know there is power. 10 stars bro.

Exelent video thank you so much, u are the best teacher ever.

Thank you sir for taking your valuable time in making this very important and informative video. Now I understand the function of the fuel regulator.

This is a great video and now I am no longer intimidated by fuel injection after this video thank you brother!!!

This is a very nice video! Thank you for taking the time to assist us shade tree mechanics

Thank you so much Mat I am now one more of you fans, I have watch the fuel trim explanation you gave and I realize I been doing things THE HARD WAY all this time I love mechanic work. I started watching u-tube and I notice most every one check the fuel trim to diagnose the problem , so I check to see how it works and that's when I ran in to you . yep am a idiot lol but not any more thanks to you sir all of the sudden now every thing make sense. I cant wait to get back home to my shop pull out my foxwell 630 pro scanner and find out my low end power lost problem on my 2004 GMC. Coming out of a dead stop I have nothing but after she hit 1500 RPM HOLD ON TO YOUR SEAT because she comes a live. thanks again and god bless you.

Matt : thanks for the lesson . I was driving my 1987 Chevy Celebrity 2.8L , it lost power and stalled . I pulled over and no restart . I had a strong gas odor . It wasn't White Castle . The gas was running out of the throttle body . I traced the vacuum line to the FPR . I put on a vacuum pump and it immediately pulled gas out of it . The diaphragm was ruptured . There is a vacuum junction on the throttle body . The FPR line is there . That's why the fuel ran out of it . The FPR is buried under the intake plenum and mounted between the fuel rails . It is not a simple replacement . I changed it and the car runs fine . Keep the lessons coming . Thanks !

Excellent video, I learned so much today.I have been working on my boat for several months with a fuel rich condition and this has helped a lot.

Thank you for giving your time to explain in a way everyone can understand, it was generous of you. I'm about to cover fuel trims and engine management in level 3 in college and it helped me understand a bit more of what's actually happening to my car currently. A new regulator is on its way ;)

THANK YOU VERY MUCH FOR YOUR TUTORIAL! Extremely interesting, I learned a lot. Every thing actually made very good sense.

Very detailed explanation, this video can save people a lot of money on parts

this is a really excellent tutorial. Finally .....at last...after years of partial insight and despite having the Bosch manual and various other manuals, its the first time that I have completely understood this aspect of the fuel injection system operation. Once you appreciate exactly how the engine vacuum together with the FPR control the fuel rail pressure and delivery, engine performance then becomes a diagnostic tool , pinpointing fuel pressure and delivery issues. thank you

Very educational...so much covered and it really allows understanding for the mechanics!!!

Great job explaining the system operation! Thank you for taking the time to make this video.

I'm taking classes but have learned more today than in weeks

Thank you for these theory type videos. It really helps the occasional mechanic who can't really afford a good mechanic nor the diagnostic equipment. Imagine Beetle Bailey in the field, it is relatively important that he has some idea how to fix things.

That is very good explanation on fuel regulators.

very good explanation about fuel pressure regulator. I just started learning about cars a few months ago from my native south INDIA. detail and mathamaticaly good tutorial. keep it . thank u.

I have never known anyone who could do an in-depth diagnose on a vehicle system without putting a wrench or some type of tool on the car. Impressive.

I once had a bad FPR leaking fuel through the diaphragm which I only stumbled across looking for vacuum leaks by sucking on the hose. Blech! The problematic symptoms varied between immediate start (one or two cranks) when hot, and extensive cranking when cold. These symptoms made sense after the fact, but I was incorrectly imagining the actual function of the FPR until this video. It did not occur to me that low vacuum meant higher pressure. My incorrect "assumptions" were compounded by my other misconception about vacuum under load! You are right -- now that I understand the proper functionality I am empowered to work on this system. Thank you for taking the time to share this!!

Very helpful, and I appreciate your explanation of the concept, it was very nice. Thank you.

Matt, you rock! very thorough explanations reinforced with live demonstration - you have A GIFT, sir. Please keep churning out the videos!

Hi there from the UK. Thanks for an informative video...my mk 2 golf has the issue of fuel being sucked through the vacuum hose, I thought it was the FPR and watching your video has not only made my understanding of fuel pressure clearer, but confirmed my suspicions..thanks once more.

Excellent explanation, I'll never leave this channel. Thank you very much.

I really like your videos Matt! Your a great teacher, you should teach automotive. Don't even think about wasting time on the negative people's comments. They are jealous that you know what you are doing and you also have a very successful RU-vid channel. I don't see them posting up videos of how to fix things. Keep up the great videos, we all love them!

Incredible and useful explanations! Thank you!

I appreciate your classes+ you make things much more understandable. also I realize after the book work on auto repair or classes which I really enjoy + next comes hands on and training which is more understandable with a good teacher. I really appreciate.

Great instructor...Clearly explained each step... Enjoyed the knowledge...

best video on fuel pressures, hope more vids come out in the future.

Thank you, that was very clear and easy to understand.

Great Video - this lady really lucked out big time also you having to help her out is a good jester - something as a simple radiator cap people don't think of replacing . Once again you did a great job .

Sir thank you so much. Im working on a 2001 Ford Expedition. Your videos have been invaluble.

the way u explain it makes me even want to learn more thanks for posting this video

Thanks for the video! Very helpful.

Definitely!!! This is one of the videos of yours which I will bear in mind to re watch again (and again), if I have problems with my toyota 1zzfe engine, in the future. Thank you so much. 😊

Congrats on the HD video! You've helped me to understand a lot more about whats going on with my car, you do an awesome job and I look forward to your future videos.

Hey matt! love the channel and I very much appreciate the level of professionalism, knowledge, and comprehension you bring to the table. On spot with the understanding and diagnosis line. It's a shame that people would rather see how to fix something rather than why it needs to be fixed, why it failed, how it works in harmony with other systems, an how the actual component or system works. As you do, I am also always stressing the point of diagnosis and comprehension of automotive systems. I shake my head way too often when trying to argue with the wrench monkey on the finer points of thorough diagnosgics. Keep up the battle between the informed and the ever so oafish parts changers!

I like that you accept that you could make mistakes and people could point at it , no one is perfect and we ALL make mistakes , that's how we learn .

You truly have the gift of a great communicator and a teacher. If I only had instructors with your ability schooling would have been much better, and enjoyable. Thank you for an excellent tutorial and keep up the great work!!!!!!!!!!!!!

Knowledge is power. I now have more power thanks to you.

Absolutely brilliant!

Very informative video, thank u

that valve on the gauge is also for priming the tool, to eliminate the air in the hose for more accurate measures and dynamic fluid fluctuations if present. as air can be compressed is not desired in the system when testing for fluid pressure. same goes for oil pressure gauge too. very good tool and many thanks for the video!

Extremely well described Re Fuel Pressure Regulator Diagnosis + Understanding...! ...Feels like I learned the whole subject (principles and practical hands-on example/s) in an extremely short period of time... will definitely help in diagnosing fuel systems... Thank you !!!

The "understanding" point you make is so damn true. True in chemistry, math, physics, everything. I just started learning about cars a few months ago, and I can diagnose so many things already just by thinking about it. Such a shame the schools seem to push the opposite point of view.

Thank you so much for this. Great learning tool.

Doing work on a 2001 Nissan Altima. I am a diy, just changed a fuel pump for the second time. Wanted to understand the fuel system more. Will watch again. Thank you

Thank you very much for your expectations I always follow your teaching in the u tube and have learned a lot... Thank you sir... MAY GOD BLESS YOU AND YOUR FAMILY...

love all ur vids.

im beginning to obsorb some of the material on short term long term trim videos, very very interesting, and also getting a better grap at this video too, its nest to understand how the sysem works, I know it takes time to learn it, but its really neat if an indidivual likes to work on cars and not just throw parts at it, keep the good work up see ya friend

I knew what caused what but now I understand why. Thanks so much for your time.

Incredibly helpful. cannot say other words than thank you very much for this complete explanation!

great videos , thanks....

thanks :)

Your explanation and drawings is very well clear. Much appreciated and thank you!

Thanks for the videos every time I forget this principles I come back and watch your videos better than a mit professor thanks sooo much

Those looking for mistakes you make are nothing but keyboard camandos.

Most excellent! WOW ! completely understand now and it increased my knowledge of fuel trim. Thanks !

With so many sensors in modern vehicles, it's refreshing to see a simple mechanical feedback loop, seemingly independent of electronic control.

LOOVVEEEE your videos man! Im a tech still trying to brush up on good diagnosis of components! You deserve to teach a class!! Once again thanks bud!

great job. I really think you should not worry about what others may think.I for one am greatful for all your kindness

The best video regarding the subject matter. I have had an issue for a while now. Losing pressure at the regulator gauge within a minute or two. From 60 psi to 0 psi in just 2 minutes. I have a return style regulator LS swap. I might start troubleshooting based on this video. Very impressed.

Wonderful job, you remind me of the great teachers I had growing up! Rock on!

Excellent video! You took great care to explain the fuel pressure regulator -- and without a jiggling camera.

great to have clear explanation of the 'why' of whats going on. great approach and great video cuase it includes the 'why'.