93 Corsica 2.2

A friend of mine has a 93 Corsica with the 2.2 liter engine. His #4 cylinder has no spark. #1 and #4 share a coil and #1 has spark. Also #2 and #3 are ok. He has replaced the coil for 1&4 and also the ignition control module but still only has spark on #1. The wires are new and test ok. Any ideas on this? Also can anyone explain how you can have spark on one side of a waste spark system? Thanks for your input.

You need to look at the wires going into the coil blocks… Especially on the 1 -4 coil. The coil pack receives a signal to fire from the Ecu…which gets this signal from either the cam sensor or crank angle sensor (combo of both actually). Since 1-2-3 have spark then you need to locate the trigger wire for the #4 plug/coil pack. Many X these wires break even though they do not display any outwardly apparent damage to the wire casing itself. Grab a multi-meter and test the other wires resistance within the plug to the coil…then see if there is a big difference between one of the wires. ALso look at the plug and the female end on the coil pack…Look for corrosion on the terminals…CLEAN ANY grunge or rust you find. ALSO … find your ground wires under the hood…and off of the neg batt terminal. Make sure that your Batt terminals and cables are cleaned and greased and tightened This is HUGELY important…it may be a faulty ground that is the issue as the coil pack is fed a ground pulse to trigger the coil packs…if it doesnt have a good source ground then it will be impossible for the ecu to administer the ground pulse you need.

I will try to find the wire color of the #4 trigger wire for you…but you can manually make up your own ground wire and distribute a ground to each of the terminals in your coil pack to see if you can get the packs to fire at will. Its an easy test to do.

SO…clean your connections… FInd any grounds under the hood and clean and tighten them… Check the wire integrity at the feed plug to the coil pack as well as the connector quality…they all need to be clean and tight. You can also start the engine and wiggle the connector to the coils to see if it suddenly begins firing…this would indicate a broken wire…