1992 318 Won't Start
1992 318 Won't Start
08-22-2010, 04:35 PM
I checked for spark at #1, no spark. Took the distributer cap off and it was kind of gunked up inside, so I cleaned all the contacts on the inside of the cap and polished up the rotor. Put it all back together, still no spark. I did take #1 plug out and it was wet and smelled of gas.
Poking around further, I took the coil wire out of the distributor cap and tried it again - no fire coming out of the coil.
I replaced the coil just on general principles and still nothing. Replaced the cam sensor (the one in the distributor cap), still no fire.
I guess its down to the crank sensor or the computer - anyone know how to tell which one? Seems if the computer was bad, I wouldn't be getting anything at all - the fuel pump wouldn't run for instance or the check engine light would be on.
I looked around for a ballast resistor, but I didn't see one. They're usually lurking about on the firewall inside the engine compartment, but I didn't see anything that looked obvious.
Is there a way to bypass the ECM and just to see if I get any spark? Any other diagnostic tests I can do?
08-22-2010, 06:05 PM
You have no ballast resistor in the 92 ignition system. No you cannot bypass the ECM, only replace it.
Are you getting 12 volts from the primary wires on the coil (key on) to ground? If not, your ASD relay (on the firewall) could have rusted/corroded contacts and is not powering up the ignition system.
08-23-2010, 09:15 AM
Well rats and mice - I sure don't want to replace the ECM without being really really sure.
There are 2 leads to the coil and one has 12 volts on it with the key on. I have a Chilton's manual and it talks about hooking a LED test light to one of the leads and grounding the tower. Then while cranking the engine, the light should flicker. I'm not sure what that's all about, but I tried it with both leads going to the coil. No flicker - on the hot side, it stayed steady on and on the other side no light.
I thought about that relay, but assumed I wouldn't get any fuel in the cylinder if that was bad since it also runs the fuel pump, no?
Any suggestions to either get around the problem or prove its the ECM are welcome.
08-23-2010, 12:28 PM
Since you have power to the coil then it's a pulse issue. That means a broken/bad connection to the PCM or crank sensor, a bad PCM, or a bad crank sensor.
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