Nick Priegnitz of Duramaxtuner was curious how the fuel pressure regulator works so we cut one open and are showing you what we found on this Diesel Insights! Subscribe to learn more about how diesels work!
I’m waiting on my new FPR to come in the mail, so I’m trying to do as much research about it before it gets here. Thank you for this video. Side note, I laughed when you said “maybe you let it sit for two years and the fuel went bad inside the regulator”. That’s exactly what I’m trying to remedy at the moment 😂
I can’t tell you how much this is helped me you’re great descriptions are very much appreciated. Look forward to seeing more of your videos. No one else even mentioned checking the low pressure side. I’ll do that and then probably end up replacing my FPR.
I just fixed my buddy’s lbz; same problem. Truck sat a lot and fpr got shitty down low. His issue went one further though - chafed wire loom allowed two wires to ground and blew a fuse. He got vane position and fpr codes, with rp at max during idle. Fixing the wires and replacing the fuse were the final fix. Crazy.
I have an LMM and I have the complete opposite happening, when applying throttle my fuel rail pressure will drop from desired and usually level out around 2000 psi. Usually this causes a p0087 but sometimes if you give it more throttle it will go jump back up to desired rail pressure. I'm suspecting the regulator wanting to slide into a low flow position or like you mentioned in the video it's just not sliding smoothly and occasionally gets stuck.
These guys are fantastic I love there products and there are great honest guys that have a passion that they turned into a business I will always run there stuff no matter what brand I drive thank you Calibrated power you guys are awesome
Awesome video. Thanks for the insight! What is the regulator actually controlling? Those o-rings don't look like they're built to handle high pressure. From some animations I've seen it looks like it controls low side pressure to the valves at the top of the 3 pistons. I guess that effectively varies the output of the high side pump?
Does a cp4 metering valve do the same thing? I have a volkswagen 3.0L tdi, and I occasionally get a surging at idle for about 20 seconds, and I get a p0087 code
Mine sounds like it’s a blown engine only when cold. As it heats up it runs perfect. Can a FPR not work correctly when cold or do I have another issue? Answers appreciated greatly
If you have a scanner such as a Snap On Verus edge one indication of a bad F.R.P. Reg. is at idle having aprox. 63% f.r.p. demand instead of about 26%. Also the engine will stumble a split second when you start it, and your desired f.r.p. is about 5,800, and actual f.r.p. is about 9,500 at idle. And there is a chance that you will be limited to 2,000 R.P.M. I believe that if you put a new Fuel Rail Pressure Regulator on after 100,000 miles it is a good thing. It will increase your power, and mileage, plus burn cleaner. I have seen an Engine Control Module which was randomly not providing power thru the purple wire with a white stripe (F.R.P. Regulator Supply Voltage). I used my new Snap On 'Pass Thru Assistant' Scanner to check for updates to my E.C.M., amazingly enough there were no updates needed and the E.C.M.'s calibration was good. Two engine starts later my E.C.M. went back to working flawlessly. I believe that the LLY Engine Control Module is a high quality unit which is actually unusual in this day and age. I highly recommend NOT having a bunch of aftermarket stuff such as a remote start. At the very least inspect all the wiring very closely after the stereo shop does the install, car toys is not a place that has a lot of competent technicians. In fact maybe 5% of the stereo shops can be trusted. The manufacturers use the cheapest solder they can find, which costs us all money because of electronic failures. Lead free, and low lead solder causes problems as well. A thing called 'silver migration' can occur on your Printed Circuit (P.C.) boards. Some electronic/ radio repair shops can address silver migration issues.
My LMM seems to have opposite condition. I was hauling a small car and went Into reduced power. Pulled over and it was loping with light grey smoke. Shutdown 2 min. Problem went away. All normal. A few days later, no WOT power. Did replace bad high rail pressure switch (forgot code). No power on hills n takes forever to get upto 65mph regardless if hauling. Think my regulator is stuck in LEAN?
Touching on the 2 stroke oil and atf thing, would it help to add some of that stuff in conjunction with a lift pump on an LML to help prolong the life of the cp4? If so, how much would you recommend adding to each tank?
@@nickpriegnitz5895 that’s a good point, guess that slipped my mind. What’s your best recommendation for adding lubricity for that pump we all know is prone to failure?
Nick ,its possible this regulator stack and the truck doesn't shutoff the engine with the keys turn in off ? my truck now doesn't want to shutoff ,I need shut at battery .Thanks brother,
I've got a brand new Bosch fuel pressure regulator and it is just buzzing when you turn the key on. I have a crank and no start situation. I'm sure that I got a new defective regulator. I just kind of wanted to see what your thoughts might be on this.
I just got a P0087 which is low fuel rail pressure. The truck idles well enough to move my Montana 5th wheel but as soon as I press on the throttle it is not happy. It’s almost that the FPR decided to stop working. When I try to drive it the Fuel Rail Pressure goes all the way down to 1.9k. I will swap out the FPR today. This all happened within 2 days. I will update this if it fixes the problem.
My truck CP3 pump not getting fuel and I did open up fuel filter and found it is half empty. My truck doesn't have any other lift/supply pump anywhere including fuel tank. Do you think it also can be the bad Fuel Pressure REgulator? Thanks in advance for your input!
@eimantas28 Just came across your comment! We do have a few CP3 cores laying around. Shoot us an email at Ben@Durmaxtuner.com and let us know how much you are willing to pay for them. Would love to work something out. Also if you don't mind me asking, are these being used on BMW's some how?
My 05’ Duramax sounds as off the motor is blown when it starts cold at 60 degrees or so. Popping and knocking bad. As the engine runs it runs better. After 20 mins and engine temp at 180 or more it runs smooth. We have no great mechanics in Houston and my diesel mechanic is lost
@@Duramaxtuner I’m actually with some great people that tuned my truck out of Michigan. Calibrated Power and they asked me for the data so I’m doing that today. The issue now is it’s running perfect the last 2 days. I’m glad but it’s frustrating because it’s not showing me the issue on the scanner and can’t figure it out. The last shipped looked for hours and found nothing and he was so mad because side he couldn’t figure it out and they also can’t charge just for looking if they don’t actually diagnose the problem.
Most diesel truck owners in TX sounds like they all have ones and they're all proud to showcase their rigs. Semis???? Drivers could care less and let it run all night while they're snoring inside the cabin.
