My truck had a p0089 the other day and this morning was loping at idle after about 10 min of driving. Sounds like a FPR to me but what is the diagnostic procedure? I have Efi-live and a tech 2 fwiw. Thanks, Kervin.
LB7: Diagnosing bad FPR?
- Thread starter Bustedknuckles
- Start date
Log the actual frp, desired frp and if you want difference between desired and actual, while at idle both in park and drive. Watch for spikes in actual rail pressure that are higher than desired. If its dancing around that's your surging idle.
Then GM s manual will tell you to command rail pressure in steps up to 160mpa and see if actual frp follows. Do this at idle and 2000rpm.
Just did this on a truck that was surging at idle, running 3 times the pressure it should at idle sometimes and dropping to 2000psi once over 18000 was commanded while driving. After talking with merchant about these parts he wasn't convinced on for but once I said surging idle with the pressures truely jumping around he said it would be a good place to start.
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Then GM s manual will tell you to command rail pressure in steps up to 160mpa and see if actual frp follows. Do this at idle and 2000rpm.
Just did this on a truck that was surging at idle, running 3 times the pressure it should at idle sometimes and dropping to 2000psi once over 18000 was commanded while driving. After talking with merchant about these parts he wasn't convinced on for but once I said surging idle with the pressures truely jumping around he said it would be a good place to start.
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Thanks guys! Exactly what I was looking for, will do that tonight. Come to think of it my buddy has one I could borrow.
x2..like already said check desired and actual. i just had the same problem, new fpr and all is good.
Well, i filled it up with fuel the night i posted that thread and added some 2 stroke oil, hasn't acted up since so i guess ill cross my fingers and wait...
Yea, I'm planning on having to do it, how long does it take? I'm thinking about just putting a complete lbz pump in when that happens.
I put the lbz one on mine as well. Replacing the fpr took about an hour. Diagnosing it running all out took another hour. ended up being a broken wire
About an hour for the regulator (Book time 4.1hrs). Just need to remove the intake horn a/c compressor and upper coolant pipe. Then unplug it and remove all three screws using a T25 torx. I found my 1/4" drive snap-on t25 standard length bit wouldn't fit straight because the bit holder would hit the regulator itself as the bolts aren't spaced out far enough. So i went to the truck and bought the long one, but then it was too long so i punched the bit out, cut it down, put a little tack of weld on it to recreate a dimple like they had on it before then pressed it back into the holder. Made it the perfect length for the job. That bit and a fine tooth ratchet makes things fast and easy.
Good luck to you.
Good luck to you.
FPR wire checl
Sorry to ask such a dumb question but how did you find out you had a broken wire. I know the thread is old but just wanted to jump in as my fpr is maxing out after replacing injectors and she was running fine prior and wanted to rule out the wires.
Sorry to ask such a dumb question but how did you find out you had a broken wire. I know the thread is old but just wanted to jump in as my fpr is maxing out after replacing injectors and she was running fine prior and wanted to rule out the wires.
If I remember rite the pump was running all out. A friend of mine Evan was in the cab monitoring it on efi at first start up and was at like 23k at idle lol. So we knew it was related to what was just done. Started following wires back and seen a frayed/ broken wire. Fixed it and all was good.