Rebuilt ‘02 3800, now no start… HELP
October 5th, 2013, 9:59 PM
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Rebuilt ‘02 3800, now no start… HELP
Just recently rebuilt my 2002 Impala 3800 due to a leaking intake gasket and subsequent blown head gaskets.
Since re-installation, we have not been able to get the engine to fire. Got it started on Ether for a few seconds, so we have narrowed it to a fuel issue.
This engine had a complete rebuild, all new seals, bearings and gaskets. Additionally, the CAM and Crank Sensors have been replaced. We know the engine has spark, this has been tested several times to be sure that it is still maintaining spark, it is. Again it has run for a few seconds on ether.
Turning to the fuel system, the fuel pump is running, building 54psi fuel pressure at the regulator. We have 12vdc at the injector plug, however we have not been able to pull 12vdc across the plug while cranking. We ohmed out all of the pins form the injectors to the PCM pins and the PCM pins to ground to ensure there was a good wiring path to ground and there was. So we assumed that the PCM was bad and sent it off to rebuild.
However, upon return and reinstallation of the PCM, we have the same results that we did prior to the PCM rebuild. We still have spark, we do not have a noid light flash at any of the injector plugs. The PCM is not reporting any DTC at all. I am able to pull live data information from the PCM to include RPM, Coolant Temp, Throttle Position, Intake Air Temp, Manifold Pressure, Mass Air Flow, and Ignition Timing Advance. We have verified that there an no blown fuses anywhere in the system and all relays are operating properly.
What are we missing that is not providing the proper Signal Pulse to activate the injectors and deliver fuel?
I have researched the Knock Sensors and understand that they have the ability to advance of retard the ignition timing. Can this impact the timing enough to cause a no start? If it does, wouldn’t it throw a code?
Are there any other sensor signals that feed the PCM that will affect the fuel delivery that I am missing?
What else could be wrong with the system that will cause these symptoms? Mind you, this engine still ran with the blown head gaskets prior to engine removal. Also, the rebuilt PCM has done the re-learn procedure and the engine does crank over, just will not fire up and run.
Please ask any questions that you need to ask and I will answer truthfully as I really need to figure this out and get the engine to fire up.
Since re-installation, we have not been able to get the engine to fire. Got it started on Ether for a few seconds, so we have narrowed it to a fuel issue.
This engine had a complete rebuild, all new seals, bearings and gaskets. Additionally, the CAM and Crank Sensors have been replaced. We know the engine has spark, this has been tested several times to be sure that it is still maintaining spark, it is. Again it has run for a few seconds on ether.
Turning to the fuel system, the fuel pump is running, building 54psi fuel pressure at the regulator. We have 12vdc at the injector plug, however we have not been able to pull 12vdc across the plug while cranking. We ohmed out all of the pins form the injectors to the PCM pins and the PCM pins to ground to ensure there was a good wiring path to ground and there was. So we assumed that the PCM was bad and sent it off to rebuild.
However, upon return and reinstallation of the PCM, we have the same results that we did prior to the PCM rebuild. We still have spark, we do not have a noid light flash at any of the injector plugs. The PCM is not reporting any DTC at all. I am able to pull live data information from the PCM to include RPM, Coolant Temp, Throttle Position, Intake Air Temp, Manifold Pressure, Mass Air Flow, and Ignition Timing Advance. We have verified that there an no blown fuses anywhere in the system and all relays are operating properly.
What are we missing that is not providing the proper Signal Pulse to activate the injectors and deliver fuel?
I have researched the Knock Sensors and understand that they have the ability to advance of retard the ignition timing. Can this impact the timing enough to cause a no start? If it does, wouldn’t it throw a code?
Are there any other sensor signals that feed the PCM that will affect the fuel delivery that I am missing?
What else could be wrong with the system that will cause these symptoms? Mind you, this engine still ran with the blown head gaskets prior to engine removal. Also, the rebuilt PCM has done the re-learn procedure and the engine does crank over, just will not fire up and run.
Please ask any questions that you need to ask and I will answer truthfully as I really need to figure this out and get the engine to fire up.
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