Fuel Pressure Regulator Diagnosis + Understanding (HD!!)

This video explains the operation and function of the fuel pressure regulator and shows several methods of identifying and diagnosing fuel pressure problems causing rich or lean conditions.
NOTE** This is my first HD video upload, as per my pledge to invest in improvements for the channel. I am experimenting with new editing software and HD formats so forgive some of the editing as I adjust to working with HD. You can select HD viewing by clicking on the "gear" icon at bottom right under the video to increase resolution. Let me know if you notice a difference in quality!

[joewahrerMotorcycleMan]

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

[xmalcom]

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!

[brandonhedges]

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.

[chrish]

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.

[itsjiraheta]

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.

[johnd]

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!

[jawadurrahman]

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

[jodyroberts]

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

[donkline]

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.

[johnsoper]

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

[stephen]

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.

[pbee]

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)?

[cobraninetysix]

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!

[jogalong]

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

[gordonfirth]

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.

[billsmith]

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 !

[theadventuresofbellaandjos]

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.

[aaronrodden]

2024 and a 2012 Suburban later, we meet again Boss Man!! I COULD not remember how to find you or your videos and by the grace of GOD I came across this video!! I remembered that you teach not only how to replace parts but more importantly WHY to replace it, how to know its that part and an intimate knowledge of how said part works!! You are the mechanic/tech that can honestly say you are GREAT at what you do because you honestly KNOW what, where and why you are doing what you are!! This is knowledge that should be just as important to pass on and never let die as anything I have ever seen! This technically makes you a legend! At least, you should be! No B.S., nothing but just legendary!!

[filibertomorado]

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.

[abderrafikbelal]

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