Faulty fuel pressure regulator causing idle surge. Vehicle wasn't acting up when I shot this video but I had captured the idle surge when it was happening.
Nice job what a pain sometimes you have to remove 6 parts just to get what you need. I like how you showed the before and after scan data and what looks bad. This stuff adds the weath of knowlage sharing... jay
The scanner I'm using is Snap-on Verus Edge which is running Snap-on software. It is a tablet so I'm also using it to access repair information online.
i was having the same problem with my lly so i decided i would try this and replaced the fpr on my truck today, after replacing it, it still does the same surge at idle and while driving, it didn’t really change, any ideas on what it could be?
90% of the time the FPR is the cause of this. Is it setting any codes? Does the actual fuel pressure stabilize if you pump up the primer. If so I'd check for air in the system. Temporarily install clear line before and after the fuel filter. Watch for bubbles.
@@PhillipBailey i’ll give that a try and come back to you, and no there’s zero codes, so i was also thinking air in the fuel but wanted to ask someone who probably knows a little more about it.
What computer are the U codes in? The P0700 is a generic code caused by the transmission computer requesting the engine computer to illuminate the MIL. You need to scan the rest of the computers especially the transmission computer. What are the symptoms?
I have a 2007 gmc cierra 2500HD 6.6 and already replaced the fuel real sensor and the fuel pressure regulator and the light still don’t want to come off.do you can help me please with that.
@@franciscohunter4422 1. Turn the ignition switch off for a minimum of 30 seconds and then turn the key back to the run position and check the Fuel Rail Pressure (FRP) regulator command reading on the scan tool, it should be near 20%. 2. If the reading is correct, attempt to start the engine. If the engine will not start, turn the key off, disconnect the Engine Control Module (ECM) connector and the FRP connector and check the Purple/White wire from pin 40 of the ECM connector C1 for opens and/or shorts to ground between the ECM and the FRP. If OK, check the Yellow wire from the ECM pin 51 for opens and/or shorts to ground between the ECM and the FRP. 3. If the wires between the FRP and the ECM check OK, with the FRP connector disconnected and key in the run position, check for voltage on the Purple/White wire using a test light. 4. If no voltage is found on the Purple/White wire at the FRP connector, check powers and grounds to the ECM, and if OK, the ECM will need to be replaced.
Hello, I know the video is 4 yrs old. I'm buying a new scanner for our shop and I'm asking around for info on scanners. We do more cars the trucks. Have and had Snap on and OTC. looks like you might be running on a laptop. That is what I'm thinking, for us but want more info. Thanks for your time.
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Nice job what a pain sometimes you have to remove 6 parts just to get what you need. I like how you showed the before and after scan data and what looks bad. This stuff adds the weath of knowlage sharing... jay
Not all heroes wear capes, thank you for the information!
Great video you know your stuff!!
If you don’t me asking but what program are you running there? On pc?
The scanner I'm using is Snap-on Verus Edge which is running Snap-on software. It is a tablet so I'm also using it to access repair information online.
i was having the same problem with my lly so i decided i would try this and replaced the fpr on my truck today, after replacing it, it still does the same surge at idle and while driving, it didn’t really change, any ideas on what it could be?
90% of the time the FPR is the cause of this. Is it setting any codes? Does the actual fuel pressure stabilize if you pump up the primer. If so I'd check for air in the system. Temporarily install clear line before and after the fuel filter. Watch for bubbles.
@@PhillipBailey i’ll give that a try and come back to you, and no there’s zero codes, so i was also thinking air in the fuel but wanted to ask someone who probably knows a little more about it.
Do you have any advice on what to do with mine. It is a 2004.5 lly. Has codes u0100 u0075, and p0700?. May be a ground but not sure where to start
What computer are the U codes in? The P0700 is a generic code caused by the transmission computer requesting the engine computer to illuminate the MIL. You need to scan the rest of the computers especially the transmission computer. What are the symptoms?
I have a 2007 gmc cierra 2500HD 6.6 and already replaced the fuel real sensor and the fuel pressure regulator and the light still don’t want to come off.do you can help me please with that.
Hello you must be setting a code or more. That would help diagnosing it. Get me a code and I'll see what I can come up with.
@@PhillipBailey the code is p0090 thanks 🙏 for responding me
@@franciscohunter4422
1. Turn the ignition switch off for a minimum of 30 seconds and then turn the key back to the run position and check the Fuel Rail Pressure (FRP) regulator command reading on the scan tool, it should be near 20%.
2. If the reading is correct, attempt to start the engine. If the engine will not start, turn the key off, disconnect the Engine Control Module (ECM) connector and the FRP connector and check the Purple/White wire from pin 40 of the ECM connector C1 for opens and/or shorts to ground between the ECM and the FRP. If OK, check the Yellow wire from the ECM pin 51 for opens and/or shorts to ground between the ECM and the FRP.
3. If the wires between the FRP and the ECM check OK, with the FRP connector disconnected and key in the run position, check for voltage on the Purple/White wire using a test light.
4. If no voltage is found on the Purple/White wire at the FRP connector, check powers and grounds to the ECM, and if OK, the ECM will need to be replaced.
@@PhillipBailey thanks 🙏 so much brother for your answer
Hello, I know the video is 4 yrs old. I'm buying a new scanner for our shop and I'm asking around for info on scanners. We do more cars the trucks. Have and had Snap on and OTC. looks like you might be running on a laptop. That is what I'm thinking, for us but want more info. Thanks for your time.
I'm using a Snap-on Verus Edge tablet in this video. There are lots of capable scan tools in my opinion. Check out Topdon and Thinktool for options.
Can this cause limp mode?
Yes I suppose if it gets bad enough where actual fuel pressure is significantly below desired fuel pressure it could.
What's an average spike of rail pressure mine goes from 3.900-4.600 at idle but not consistently all over the place
If it looks like the pattern at 2:30 in the video then I'd change the regulator.
How do you check the power to the fuel pressure regulator
You can use a scan tool to see what your fuel rail pressure is vs the desired fuel rail pressure or use an oscilloscope.