Trouble in the rain...

Topic: Trouble in the rain... (Read 1302 times) previous topic - next topic

Trouble in the rain...

April 06, 2006, 09:17:23 PM

The past two days have been the first really wet days around here since I rebuilt the engine in November. And sure enough just as it used to do, my car goes all to hell. It runs rough and dies if I don't keep the gas up. Irritating because it has a new HEI distributor and wires. I rigged it up so that a relay routes power from the battery directly to the distributor when activated by the old factory coil wire. I did drop that distributor on its head when I was installing it and the uppper coil casing broke but I can't see any evidence of cracks in the main cap except for the odd appearance of little oil speckles in a ring around the inside as if throw there by the rotor. It's not alot of oil by any stretch, I don't think it's even fresh but still. And there's something else that tends to draw my attention away from the distributor. On both days while I was driving and the car was warming up and starting to idle stable, I'd turn on something electrical like the heater, the radio, or both and the engine would promptly stall again. Kinda weird though, I mean the harness draws power from an exposed bolt near the battery, if it was gonna bleed electricity wouldn't it be from that bolt? Can anyone point me somewhere? By the way it's a carbureted engine, the computer doesn't have any influence on it.

Trouble in the rain...

Reply #1 – April 06, 2006, 11:44:50 PM

Simple enough to check - on a dry day with the engine running, spray some water on the distributor with a squirt bottle and see if the engine stumbles or dies. If you do this in relative darkness you can also watch for errant sparks.

Trouble in the rain...

Reply #2 – April 08, 2006, 05:24:08 PM

Okay I just bought a multimeter, something I never had access to before. I poked and prodded the distributor a little and I decided to try touching one lead to the battery (-) terminal and the other to the ground lead on the distributor's ignition control module. I did this several times and the meter read 47 in the 200k range, or 47,000 ohms if I know what I'm doing. Granted I don't know what's normal but that seems pretty high. This is a Procomp HEI distributor that I only installed in November. Thoughts?

Trouble in the rain...

Reply #3 – April 08, 2006, 07:16:24 PM

Something else I noticed....the distributor itself has a large open slit in it's side for the vacuum advance. In my case it's facing forward. The fan would have to be ramming whatever happens to be in the air right into that hole. Some dielectric grease will take care of that but does every distributor have this? Strikes me as a design flaw.

Trouble in the rain...

Reply #4 – April 08, 2006, 10:46:51 PM

Be sure to disconnect the battery before using the OHM meter.

Trouble in the rain...

Reply #5 – April 08, 2006, 11:55:16 PM

He doesn't have Duraspark, he's got an aftermarket HEI distributor.

sum_weirdo: I'm not sure what the specs are for your aftermarket distributor but I'd assume it should be the same as a stock GM HEI distributor. As for the vacuum advance slot, it might let moisture in (remember, GM's have their distributor at the rear of the engine so water intrusion wouldn't be an issue back there). The only thing I can recommend is looking at the inside of the dist and if it's filled with crud, plug the hole.

Here are instructions on how to test factory GM HEI (using an '88 Vette as an example because Mitchell OnDemand doesn't have any info on ProComp HEI distributors):

Trouble in the rain...

Reply #6 – April 09, 2006, 01:30:04 AM

I think I may have made a mistake testing the ground. I've since discovered that the black wire is the main ground for the distributor and it tests at 0.5 ohms. So what exactly is the green wire marked with a G on the ignition module?