Needs help diagnosing itermittent ignition problem

[Woody Mammoth]

So far twice this week, I could not restart my 91 Grand Wagoneer, after driving around for a while. Last week it takes only a few minutes, but yesterday it takes about 45 minutes to cool off before it will restart again. Here is what I know is good, good battery and starter(keeps cranking), got fuel (can see and smell vapor when look inside carb). Here is what I checked so far according to Haynes manual. Primary and secondary resistance on the ignition coil are measured OK also. There is battery voltage at one of the terminal at ignition coil and electronic ignition module (one side of 2 prong connector), IF both coil and module is disconnected. With ONLY coil connected there is 12V at coil terminal, but if I plug in the 2 prong connector to ignition module, it drops to ~6V. Is that normal?

I haven't got a chance to take measurements at distributor pick up coil assembly yet.

In the middle checking all ignition related wires, red conductor(one of two at white plastic connector) at alternator, got so much green color rust and got pull out. So I had to push that back in best way I can with limited tool so I can get the jeep started and drove home. At least gauge shows alt. was charging. Is the connector an autoparts store item? where I can crimp a new one back on?

Thanks :confused:

[Bob Barry]

Heat-related no-starts are usually a sign of a failing ignition module (silver finned box on your driver's-side fender; probably run about $60-$90 for the style with the weatherpack connectors like you have).

For the alternator, that plug is an ordinary replacement item found in the "HELP!" aisle at your local chain auto-parts store. Cut the original wire back to where the copper is good, solder and shrink-wrap the wires for the new connector on there, and plug it back in.

That should take care of most of your problems. I've done the same to my '88. Also check the condition of the connectors for the distributor, as they can fail due to heat-induced brittleness.

[Rich 89 Gr. Wag]

Ditto on the ignition control module, and it's an easy fix. Just bolts on to the d/s fender wall with two bolts. That took care of my intermittent starting on my 87 Grand Wag.