Hey guys been a while since I've messed around with my truck but it's time I dive back and put these issues to bed because I am at a loss on what to look for.
A little back history, after getting out of my mess of a used built motor I bought, I found a motor from a member on here out of a running wrecked truck. After putting the motor in, all was well for a short period of time. Rail pressure was hanging up and taking a while to come back to desired when slowing down so I attributed it to a bad FPR. I had a brand new from GM LBZ pump in a box that I had on my built motor so I decided to swap it out. Tune was reflashed to work with the LBZ pump, but I have max rail pressure at idle now(171mpa) demand is correct though at 38mpa. I thought the wiring could have been damaged so I ohm'd out the wire to the bale connector and then to the ECM and it seems to be good. I checked voltage on the two wires (purple/black and yellow) and have 5v on the purple wire and .3 volts on the yellow. I have some codes which I've been trying figure out if they are related and could cause the ECM to be outputting the wrong voltage.
P0090
P0089
P0108
P0380
P0540
I know 380 and 108 and glow plug and air intake heater codes that in not concerned with as I have bigger issues and I don't believe those are tied to the rail pressure issues.
ECM has been verified good in another truck with an LBZ pump. The map and baro I believe are hooked up properly. I swapped rail pressure sensor with another I had and get the same results. Cleaned MAF with no change. Is there something in missing?? What other reference signals control what is outputed by the ECM that I can check? What has my very confused is that demand rail pressure is right on but actual is not following. So what the hell tells the ECM to output the right voltage? Any help is greatly appreciated
A little back history, after getting out of my mess of a used built motor I bought, I found a motor from a member on here out of a running wrecked truck. After putting the motor in, all was well for a short period of time. Rail pressure was hanging up and taking a while to come back to desired when slowing down so I attributed it to a bad FPR. I had a brand new from GM LBZ pump in a box that I had on my built motor so I decided to swap it out. Tune was reflashed to work with the LBZ pump, but I have max rail pressure at idle now(171mpa) demand is correct though at 38mpa. I thought the wiring could have been damaged so I ohm'd out the wire to the bale connector and then to the ECM and it seems to be good. I checked voltage on the two wires (purple/black and yellow) and have 5v on the purple wire and .3 volts on the yellow. I have some codes which I've been trying figure out if they are related and could cause the ECM to be outputting the wrong voltage.
P0090
P0089
P0108
P0380
P0540
I know 380 and 108 and glow plug and air intake heater codes that in not concerned with as I have bigger issues and I don't believe those are tied to the rail pressure issues.
ECM has been verified good in another truck with an LBZ pump. The map and baro I believe are hooked up properly. I swapped rail pressure sensor with another I had and get the same results. Cleaned MAF with no change. Is there something in missing?? What other reference signals control what is outputed by the ECM that I can check? What has my very confused is that demand rail pressure is right on but actual is not following. So what the hell tells the ECM to output the right voltage? Any help is greatly appreciated
