Discussion:
Engine will not start

Customer lift with a GM 2.4 engine. Have no idea what has been done to this thing prior to getting a call. However, all active codes have been resolved and log cleared. When the key is turned to the run position, you can hear the fuel relay and the LPG solenoid engage, but they both drop out after about 5 seconds and I lose fuel and fire. This happens in either key position, run or start. I am losing the negative signal from the ECU to the fuel relay, which supplies the 12 volts positive feed to the ignition coil, LPG solenoid and various other components. Pretty much all the basic angles have been covered, including replacement of the ECU. Again, I have no codes. The only thing I can find that leads me to a possible bad VSM is the fact that I can unplug any sensor, except the crank or cam position and get a code. The crank and cam do not trigger a code when unplugged.

My intentions were to state the problem only, hoping for an unbiased approach, but I figured there would be less back and forth with all info to date. So, here we are. Any thoughts? Bad VSM or am I missing something else?
  • Posted 10 Sep 2022 02:33
  • By AMH_Tech
  • joined 20 Nov'14 - 8 messages
  • South Carolina, United States
Showing items 1 - 2 of 2 results.
Could you tell me what you found? I'm experiencing the same issue here.
  • Posted 26 Apr 2024 03:29
  • By Mihof
  • joined 26 Apr'24 - 1 message
  • Texas, United States
The crank and cam sensor go to the ECM not the VSM. These engines have had issues with the wire harness between the ECM and engine. The negative signal drops out if the engine is not cranking. Also issue with connections at the ECM connector. Back probing causing spread pins and poor connections when testing for continuity. The ECM and VSM are last resort. Good Luck
  • Posted 1 Oct 2022 03:16
  • By garland_m
  • joined 16 Oct'09 - 212 messages
  • Virginia, United States
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