I bought my first Duramax (2006 LLY) knowing it had a low fuel pressure issue. On the scan tool, the balance rates were within the +/-4 in park, but we were unable to boost pressure due to the DTCs coming back almost immediately after clearing them. This truck has 4: high voltage A/C circuit, glow module, the low fuel pressure, and one other I can't remember.
Starting with the least expensive and working my way up, I did the two-part Seafoam fuel system cleanout (one bottle in the tank and one bottle in a new fuel filter). This cleared a lot of the "rolling coal" at acceleration and even lessened an injector knock the truck had when I got it. It did not fix the loss of power after about 2500RPM, so I moved to replacing the injector pressure relief plug on the drivers-side fuel rail. I installed the racing plug. As most everyone knows, I had to remove the glow plug module/relay and the back plate to get to this plug.
After reinstalling the glow relay, I fired the truck up and it idled fine. To my surprise, when I left my driveway the truck had regained all the lost power! Stoked, I took the truck for a drive, and about 5 minutes later, the engine began to lose power after 2500RPM again. I checked the plug for leaks and there were none.
On a hunch, I unplugged the 31-pin connector to the glow relay, waited about a minute and hooked it back up. I drove the truck again and had all the power. 5 minutes later, the same thing happened, loss of power after 2500RPM.
During this whole process, the check engine lights stayed on (what I expected).
My question is:
Will unplugging the glow module/relay and plugging it back in trick the ECM into allowing acceleration briefly and then the truck goes back to power loss?
My next move is to replace that relay (since I already have a glow module code in the truck).
Does this sound like a bad pump, or is the relay somehow the culprit???
THANKS IN ADVANCE!!!!!!
Starting with the least expensive and working my way up, I did the two-part Seafoam fuel system cleanout (one bottle in the tank and one bottle in a new fuel filter). This cleared a lot of the "rolling coal" at acceleration and even lessened an injector knock the truck had when I got it. It did not fix the loss of power after about 2500RPM, so I moved to replacing the injector pressure relief plug on the drivers-side fuel rail. I installed the racing plug. As most everyone knows, I had to remove the glow plug module/relay and the back plate to get to this plug.
After reinstalling the glow relay, I fired the truck up and it idled fine. To my surprise, when I left my driveway the truck had regained all the lost power! Stoked, I took the truck for a drive, and about 5 minutes later, the engine began to lose power after 2500RPM again. I checked the plug for leaks and there were none.
On a hunch, I unplugged the 31-pin connector to the glow relay, waited about a minute and hooked it back up. I drove the truck again and had all the power. 5 minutes later, the same thing happened, loss of power after 2500RPM.
During this whole process, the check engine lights stayed on (what I expected).
My question is:
Will unplugging the glow module/relay and plugging it back in trick the ECM into allowing acceleration briefly and then the truck goes back to power loss?
My next move is to replace that relay (since I already have a glow module code in the truck).
Does this sound like a bad pump, or is the relay somehow the culprit???
THANKS IN ADVANCE!!!!!!
