On my '89 vette, over the past 3 years there is a funny problem - I have been working at it all this time ...plus I gave it to the dealer for a few days and also pep boys. The dealer was smart enough to say they couldn't find the problem and pep boys changed out most of the ignition components and did not fix the problem.

There simply appears to be no spark when starting the engine sometimes. The real problem is that it is intermittent - it fails about every few months or so. The engine turns over but will not 'ignite'. If I wait a few minutes to a few hours, it will start. The distribuor, harnesses, ignition module,cap,rotor all has been replaced.

Now here's the key - if I take the distruber off and regrease the ignition module (ignition module di-electric grease) it always fixes the problem and fixes it for at least a month or so. Now I carry around the few tools I need to do this - but the question is "why does this fix the problem?" Am I just doing something else that seems to fix it. Does the electrical contact grease have to be special (using high-temp 3M ignition module 'clear' grease).

Any sugestions or insights would be helpful - also considering it to be intermittent - is there anything else I can check when the problem occurs again to isolate it. I was able to confirm that no spark was present when the problem occurs.

thanks,
barrypaul

 

Do you really have to regrease it or could it be that you're moving something in the process of regreasing that is correcting the problem temporarily? I think I'd take a really good look at the wires and connectors around the distributor. Might even want to look at the coil assembly. You're bouncing that around doing all this. Maybe there is something funky in there.
Good Luck
Walt

 

The grease is a silicone grease meant to increase the thermal conductivity of the ignition module to the distributor mount. I doubt very much that the grease has anything to do with your intermittent. However, moving the wires around and/or plugging in the ignition module reconnects a wire that with time disconnects itself and won't allow a spark. These connectors are crimped onto the wires and are normally very reliable connections. If the no spark condition remains for a reasonable time, it should be possible to probe the connections and find which wire is open circuit and either solder that connection or recrimp it. for all the trouble it has caused you, you might try soldering every crimp connection inside the distributor and soldering the terminals on the plug from the wiring harness that plugs into the distributor or even installing a new plug on the wiring harness.

 

How did you diagnose it to be lack of spark?
You state replaced harness so its not the connection.
Does it only happen when hot?
Hows your battery?
How many miles?
Hows the starter?

 

Just went through the same thing, sort of. In the end I bought a module too. Never occured to me that it could be bad. After two weeks of cursing I finally gave up and sent her out to be fixed. 5 modules later, he finally found one that my engine likes to use. Go figure...... :crazy:

 

Your oil sending unit is also located near the distributor. You may have a loose wire there or a sending unit that is going bad. The ECM will not allow the engine to run if oil pressure is below 4 PSI.

 

Maybe a wiring problem at the ignition switch.