Hello, I am currently working on a 07 lly c5500 that has an issue i can't seem to work out. Truck came in with p0087 code and obvious rail pressure concerns. Diagnosis of low pressure yeilded a new injection pump, and one injector that had a high return rate. After replacement of those parts as well as a FPRV shim kit i no longer had rail pressure concerns and no more limp mode. During a test drive with trailer on warm (90) day, I was suprised with a reduced engine power message on IPC with no rail pressure problem. Only DTC setting is a P0168 fuel overtemperature, which according to TAC will not cause a reduced engine power light. So i looked at the snapshot i took at time of REP light and the DTC P0168 set at the same moment. Fuel temperature was at 239 during this frame and it states in the DTC conditions for setting that it must see 252 for at least 5 seconds to set the P0168 code, weird. I then attempted to turn that DTC off using EFI, I also allowed more rail pressure per fuel temp. After tuning DTC continued to cause REP light and dinger to come on although DTC was invisable to a TECH 2, it could still be read with the V2. I then tried a fresh GM tune, and allowed it to ramp down the rail pressure to control fuel temp. That test drive it would only get to 235 before being held back by stock tune, but yet the P0168 still set at that temp, Any Ideas as to why I can not shut that code off and why it is setting below the stated parameter? Any Ideas would be considered and appreciated, thanx
EFILive 07 C5500 LLY problem
- Thread starter DTdiesel
- Start date
it is a medium duty, it's basically a LBZ, same computer ect, just like an 06 pickup LLY, cept this has a completely different os, cuz like the light I got coming on is a medium duty only thing, and unfortunately it doesn't seem to work putting in a light duty LBZ/LLY tune, lol, ie it doesn't run for some reason.
thought I would update, tried unplugging fuel temp sensor and removing associated circuit dtc's to see if that would keep the REP light out, it did, unfortunately that limits rail pressure to 17.5 regardless of how you have B1057 setup. Any ideas, seems to be that these parameters are unable to be changed with efi live. And for some reason aren't following GM's rules either, there's some missing information