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I could sure use some help with this one and is greatly appreciated. Here we go... Early December was called out to customer for a hard to start and rough running condition. I found the distributor not firing correctly and badly out of time. Also noticed that when I turned the key to the on position, the engine would rotate backwards about 1/4 turn. I set timing at TDC and tried again. Condition still remains. Tried 10-12 degrees above TDC. Still same problem.Replaced distributor. Installed new wires and plugs. Unit then started cranking and running ok. Still had abnormal cranking time. Sent it back to service. Was called back out today for a no start. I troubleshoot for 4 hours. Here is what I found. Distributor only fires when I unplug the 4 wire plug at the distributor. Engine will run like this momentarily then stall. I checked voltage supply on wire C of the 4 wire plug. It has 1.3 volts. My understanding is it should have 5 volts there. Ground is good. All engine grounds are good. Ignition control module has 754 ohms resistance. Coil is good. I did find a few wires coming off of the ECM/Timing control module that were rubbing the air intake hose and bare. I also found 2 fuses located on top of the left side valve cover that were blown. Replaced fuses. Still no change. Tried unplugging CTS. No change. Bypass oil sending unit. No change. I am at a loss. This unit did have a check engine light on. I have never seen this style ECM. All wires are orange and there is no square 4 prong diagnostic port. There is a inline 4 pin diagnostic connecter above the intake. I tried jumping A and D. Check engine light does nothing. I am at a complete loss here. Has anyone seen this issue before or familiar with this system? Every 4.3 I have seen will run without ignition timing control module. So even if it is bad, it should still run.
  • Posted 27 Feb 2015 12:44
  • By LTS1
  • joined 18 Dec'13 - 74 messages
  • Florida, United States

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