This is going to be a long one so bear with me. 2003 lb7 was bought at a used car lot and driven 2 hours home. the truck ran fine, then the truck was started and driven 5 miles and shut off. when the truck was restarted it went about 30 feet and smothered out and would not restart. We used EFI Live and found a p0370 code. We immediately unhooked the WIF sensor and fuel heater and isolated them from any possible grounds. The truck still would not start. We logged fuel rail pressure while cranking and it only had 250 psi, but it showed this value constant whether cranking or sitting still. Definately a little odd. We then replaced the cp3 pump and found where someone had been there before and installed a junk yard pump and found a couple of instances of wiring harness repiars going to the FICM. We installed the new pump and the truck still would not start, but now the rail pressure sensor is maxed out showing 26000psi. We can get the truck to start and run if we unplug the FPR and let the truck make max rail. We can also trick the computer using a variable resistor in place of the rail pressure sensor and change the value by varying the resistance. Now for the really crazy part, the truck now has a code for 5volt reference and the throttle pedal not working. I can sweep the tps while watching the value with efi and it does not make any affect but I can raise the speed of the motor using the DVT function. So, has anyone seen anything like this? Oh yeah and this is a Cali emmsions truck that has made its way to TN. I am going to replace the rail pressure sensor and see if it will give a true value but the other electrical bugs are really throwing me for a loop.
LB7: electrical problem?
- Thread starter anrchydiesel
- Start date
Update: Replaced the rail pressure sensor and it did not change any thing. I am sure there is a problem with something on the 5V bus but I am not sure what all is getting power from this group. Can someone tell me if the EGR on a cali truck has 0-5 volt sensors?