Mechanics

GRAND ENGINE STARTED TO MISS

1990 Mercury Marquis • V8 2WD Automatic • 90,000 miles

1990 Mercury Grand Marquis mileage: 90,000. One day when I passed a car and the engine started to miss. I tested the spark and the #2 cyl had no spark. I then tested for spark at the cap to eliminate the plug and wire and had no spark coming out of the #2 tower, but if I raise the throttle, it will get a very weak spark. Just to let you know I have replaced cap, rotor, coil, module and pick-up. The real problem is if I shut the engine off and restart the miss goes away and I can make it miss again by flooring it under a load. When the miss is there it's always #2 no spark and with the spark tester on #2 I can get it to spark by unplugging the timing spout connector and when I plug it back in it will lose spark again. If I leave the spout connector out it won't miss or with spout in and restart engine as long as I don't floor it under a load. I bought a wire diagram book from Ford factory and the circuit# is 324 which is a yellow with light green stripe. It goes from TIF module to the spout and from the spout to pin 36 at the EEC module. Pin #36 on the EEC description says transmission overdrive switch to heat module. I don't know what the heat module is and 324 circuit seems to end at the EEC. I was wondering if it is part of the EEC and if the EEC is what is bad?
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2CarPros-Archives
November 19, 2010.



In view of the testing you have done, would be to try replacing the EEC with a known good unit

Tiny
2CarPros-Archives
Nov 19, 2010.