Why no spark when all else is checked out & OK on each of two rebuilt PCM units?

  • 124,000 MILES

After many repairs this car was running with no fault codes for about two weeks when there occurred a huge misfire problem on two cylinders firing off of the same coil. Using Ford factory shop service manuals I did all of the trouble-shooting & pin-point tests that could be done without the 104 pin breakout box and they led to "Ignition Control Module Failure" as the diagnosis. In this vehicle the ignition control module is integrated into the Powertrain Control Module (PCM). After getting two refurbished & reprogrammed PCMs and having the PATs system reprogrammed to match the ignition key each time, the engine would not start either time. The failure mode in each case was as follows: 1. The engine cranked over just fine; 2. The fuel injectors were delivering fuel to the cylinders; 3. There was NO spark at all out of any of the spark plug wires; 4. There is proper voltage going to the coil pack on the proper wire of the connector; 5. There is proper continuity of the other three wires to pins 26, 52, & 78 of the 104 pin connector to the PCM; & 6. The engine at least ran poorly before but now it doesn't run at all with either replacement PCM. Is there any fix that I could have missed without having to buy a 104 pin breakout box?

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Wednesday, August 1st, 2012 AT 10:08 PM

1 Reply

  • 49,783 POSTS

Was this originally scanned for codes and fuel pressure checked? Waas the cam and crank sensor connectins checked as well as sensors them selves?

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Wednesday, August 1st, 2012 AT 11:15 PM

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