no spark in 90 z24

one of my friends has a 90 z24 and were trying to figure out whats wrong with it. we have pulles all 3 coil packs off and can't get them tested anywhere(might take it to a mechanic tomorrow). we replace the peice behind the coils becasue it was bad. were not getting any spark and can't really tell if the coils are good(yet) so I was just wondering if anyone had any suggestions on what may be wrong with it or similar problems.

If the module was bad (tested I presume) then you may just try reinstalling them. Both module and coils rarely go bad at the same time.

i have a 86 cavalier with 2 liter 4 cylinder. no spark last week. took the module to Auto Zone and tested o.k. so i bought a coil. ran a minute and died- no spark. took the coil back to auto zone and changed it out. ran 5 minutes and died. took the module back and they said it was still o.k. i bought one anyway and installed it. car has now run 3 days no probllme. moral to the story is, the module test machine may "shock" the module and close circuit so it will test o.k. and even run for a few minutes in the car.--- 95% of the time you have no spark, you need to replace the module in the distributor.

umm there is no distributer that I see on this car just 3 coil packs and a backplate (tested bad), which we replaced. the car will not start at all, were in the process of getting wiring diagrams and checking the route from the ECU, anyone know whre I could download a fsm from? someone at napa told us there was some ingition box between the engine and transmission but we can't seem to find it if anyone knows what it is where it's located or even what it may look like the help would be very appericated.

Steve11 is a little off. This car has no distributor. No GM car does anymore. Modules can fail when hot and teat good when cold but that is rare. You should check your crank position sensor. A Haynes or Chiltons manual will explain how. You will also want to check the harness and plugs. Also check your oil sending unit, without oil pressure it will interupt spark. When/if bad you can lose spark even though you still have oil pressure. Good Luck.

Crank Position Sensor, located on the backside of the motor IN THE BLOCK secured by a 8 mm bolt. It has two wires that clip into it. In fact I believe that they are yellow and purple. The sensor gets bathed in oil and tends to crack from the heat it is exposed to. It may expand so as to make removal difficult. Remove your front "dogbones" and tilt the motor forward for more room to work. The sensor is just above the oil pan in the center area of the block. Get in there and replace it, they are not that expensive($20). Do not bother trying to test it, as they are a common problem on all GM 2.8 and 3.1L motors. If you want some really indepth info on your motor, try here : www.60degreev6.com Hope this solves your problem. -Chris