dream_garage

iTrader: (8)

Hey everyone, just a little background info on my situation here. Bought a 94 touring with a blown motor. Pulled it, rebuilt it, and back in the car. This is my 1st rebuild so as expected i'm having some issues. The car has had some trouble starting and when it did it had trouble staying running. I started with the basics, fuel and air. I've got fuel at the fuel rail and my plugs are comming out with gas on them so presumably i have fuel. Checked for spark. Only 1 plug is firing, the front trailing. As I am learning, this is a minor problem and could have SOMETHING to do with why the car doesn't start. I've check the wiring diagram and some past threads on ignition and have read that the coils could be the problem. I've checked all the grounds and even test the coils for resistance per the FSM. I then put them in the oven and tested again. There was no difference in the test whether hot or cold, they pass the test with 0.6-0.7 ohms of resistance on "a & b" and the leading coil's outputs read 12.5 ohms. I have another set of coils on the way(thanks to drama) just in case. I've checked the coil harness for 12v on the upper terminal and i do have 12volts. I've read that it is good to test the ground while cranking the engine with a test light. I currently have the UIM disconnected. I didn't want to crank the engine with it off, for fear of, well cranking with it off ! Is there anything on the UIM that if disconnected will cause no spark. the TPS or IAT for instance ? Do i need to reinstall the UIM and senors before testing the grounds or am i just being paranoid ? Anything i'm missing that would cause only the front trailing plug to fire other than bad coils ? Sorry this is so long and thank you to anybody who takes the time to read this and trys to help me out. -Gabe

GoodfellaFD3S

iTrader: (213)

Hi Gabe,

sounds like you're on the right track. Either your Leading coil and rear trailing coils are bad, or the wiring harness and/or connectors are bad.

The car definitely will not start off of just one trailing plug.

Also, how old are your spark plug wires?

Btw, kudos for doing your own legwork and testing parts out via the FSM before posting for help, some new owners on this forum of late expect the senior members to do all the work and spoonfeed them everything. So thanks

dream_garage

iTrader: (8)

Thanks, believe it or not the car has started a couple times with only the front trailing firing. The plugs and wires are new. Is the anything wrong with cranking the car while the UIM is off and disconected ?

GARCO MOTORWORKS

Disable the fuel pump because if it did start , I do not think it will , it would be wide open and over rev . You could put the working Ing trigger wire to the non working coils to see if the coils are good .

dream_garage

iTrader: (8)

The fuel pump is currently disabled. I'm assuming what your calling the ignition trigger wire is the plug on the one working coil ? I've taken the front coil's plug and moved it over to the middle or leading coil and i still have nothing. Thanks for the suggestion.