Well you've shimmed the FPRV, checked for leaking fuel lines, DVT tested the CP3, have no lift pump to create issues, and changed the fuel filter..have you flashed a 100% stock tune? If so and it's still having issues I'd stick to what I said earlier about the motor holding fuel psi parked but not with a load...may very well be a bad CP3 in my opinion
LLY Issue's...Need Advice
- Thread starter bullfrogjohnson
- Start date
I just use the rail pressure control and type in 180mpa.
Are you sure its actually going to 180mpa? You can type 300mpa into the box if you wanted to, and it will "say" its at 300mpa, but in reality it will only go as high as the ECM will allow to manually be commanded (like If you used a Tech 2)...which is 160mpa on the LB7/LLY, or 180mpa on the LBZ/LMM, or 200mpa on the LML.
Ben
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I was logging it while I commanded 180mpa and the actual rail was reading 26,xxx psi.
hmm interesting. I tried that several times on two different trucks and still couldnt force it to command over 160mpa. Maybe a different operating system or something?
This sounds like the same problem my LLY just started a couple weeks ago.
I still kind of think its the FPRV when I bottle test it with the scan tool and go instantly to 160 fuel will start coming out, but sometimes when I do it it dosent. I drove with a bottle test and instead of diesel going into the bottle it started flowing from the 3/8 hose you block when you do the bottle test.
So when I log it fuel pressure does find even at WOT untill the boost comes up to normal at wot and it starts to ramp in the fuel then the pressure falls to about 50mpa and stays there.
But what is wierd is that the highest rpm it will go is about 2600-2800 and its like it hits a rev limiter there but it is really violent and you can see and hear it cutting on and off. In the logs it shows the rpm stop then acutally go down which seems to me that absoultely no fuel is getting to the engine even though pulsewidth rises to about 3200-3800 at WOT to try to compensate for only 50mpa of pressure?
If you try to hold it there it will eventually try to shift I guess and it makes the worst bang tie-up feeling in the trans also?
I still kind of think its the FPRV when I bottle test it with the scan tool and go instantly to 160 fuel will start coming out, but sometimes when I do it it dosent. I drove with a bottle test and instead of diesel going into the bottle it started flowing from the 3/8 hose you block when you do the bottle test.
So when I log it fuel pressure does find even at WOT untill the boost comes up to normal at wot and it starts to ramp in the fuel then the pressure falls to about 50mpa and stays there.
But what is wierd is that the highest rpm it will go is about 2600-2800 and its like it hits a rev limiter there but it is really violent and you can see and hear it cutting on and off. In the logs it shows the rpm stop then acutally go down which seems to me that absoultely no fuel is getting to the engine even though pulsewidth rises to about 3200-3800 at WOT to try to compensate for only 50mpa of pressure?
If you try to hold it there it will eventually try to shift I guess and it makes the worst bang tie-up feeling in the trans also?