Started a month ago. I then replaced the dist cap, rotor, and ign module. I was getting a soft error code in EBL for ign module BTW. Repalced the Accel module with a Delco unit. Needed cap and rotor for sure on inspection. Replaced those with high quality units. Car ran remakably well after. My AutoMeter Tach was clean and smooth. Prior it would break up and needle would get wild at WOT.

Car sat for 10 days due to heat here in WI(100+) on trickle charger. Washed it and put back in garage. Following day car ran OK but when I did a WOT under load the engine broke up and tach went wild. Did so again today. I may have some water contamination? Could water get under cap? Dust cover is on. Lead to ECU from distributor has a feed to Innovate WB controller for RPM read out for Innovate log. I cant remember if that original line was cut or just output was wrapped around with insul removed. I will check that.

In analysis I see event with RPMs eroneously showing false number like 4000 then 2000 then 4000 then 6375 in each successive row under load WOT. DC% drops correspondingly following eroneous RPM reads yet fuel sPW stays the same? How can that be?

 

It's always something ... eh Ron ???
Assuming you greased the module well when installed, it would be surprising you got any moisture in there ... but ya never know ..... Could be the pickup is going bad as well .....
I have heard of getting a bad module right out of the box .... I know they don't like the heat ...
Sorry to hear this man ..... hope you find the fix soon .....

 

yes module well greased(came in box). I hear pick up coils fail all at once? Two years ago it tested fine.

I did 3 WOT runs today #3 of 3 was OK. No breakup. Pulled 1st gear from rolling start to 5500 rpms. #1 and #2 failed.

No error codes in EBL!

I think it is a sloppy wiring job or water infiltration or both. I recall me directing water at windshield from side of car near the hood at dist. From now on I will place a plasticbag over dist !!!

 

Ron,

Are you using a CD or MSD box for ignition? as you may recall, I had an
MSD 6A on my 84 for quite a few years. It finally died, but before that, I had a problem w it until I found out I needed a low resistance contact button under the coil. It would run fine for a while and then start to break up. Just some previous experience. Also, I used MSD wires so the insulation didn't break down with the hotter spark.

 

Could be distributor ionization if humidity was high enough.

 

Hi Dom: I have an Accel "modblaster" coil in cap. Wires are Mallory and nicely routed. I inspected then 4 months ago when I added some nice retainers. Stock disintegrated over 27 years.

I think it is water infiltration. I am going to pull the tap to RPM output to ECU and inspect connection. It may be wound. I will solder it and shrink wrap.

last WOT run was AOK so maybe the water had evaporated?

 

Sure sounds like it. You had an issue with that new cap being a little hard to push on so seal may be less then optimum.

Also a project for next winter would be replace that pickup coil. You'll find the covering of pickup coil wires powdered/disintegrated, green corroded copper wire coils with nasty green corrosion. Just yuk. This could be attracting the extra moisture or even be the underlying issue?

Along these same lines my small cap EFI distributor is disgusting inside again (brown dust, green corrosion on pickup coil plug, wear) at 30k, but my LT1 distributor is spotless inside at 125k? OK no pickup coil but also vented! So for kicks I'm going to add a Opti Vent system to the new small cap EFI distributor. Results will be reported in 3 years or so...

 

Eagle mark just reminded me that due to the high voltage I drilled a few holes in the cap for venting purposes.

 

In the dust cover for coil or dist cap?

 

Distributor cap, where all the high voltage open spark is happening. But this can have ill effects if it rains.

If you look at an Opti distributor vent system it is vacuum to distributor and vent hose with filter to air after air filter so pretty dry air going in even in rain. It is a tiny amount of air moving. IIRC there is another valve or limiter in there as well.

 

Are you venting hot air or moisture or both?

I am thinking a 1/64 inch hole or two but at front/of cap as rain and car wash tends to be directed at rear of dist cap.

I thought it would go away as car in garage for five days in 90+d temps but it reoccurred today. What I am seeing is electrical interfearance at tach and in WU datalogs. The RPM is eroneous in log jumping to 6375 along with visual on tach. Sept of 2010 I fouled plug #2 only(oil) but that would not affect my tack nor my rpm in log. Plugs are two levels cooler for N20 but I have not sprayed yet this year. Maybe 5 times last year. I am thinking it is coorsion at the female tach harness(two of them) as the module side is new OR corrosion at the output to Innovate controller. What you think?

 

I've seen moisture inside cap for long times. Should pull it off and look? When engine is hot you'll see moisture on top, near coil. Dry cap and blow out all of distributor with air.

Since you've had the same issue before, I'm not sure it is moisture or if venting will help?

Venting is a good thing for avoiding condensation that can get in but not out top once in, but the real benifit has to do with all the electricity causing havok, I don't know the exact techncalities.

 

Once there is moisture in the cap area it won't leave on it's own. Pull the cap off and use a hair dryer on the inside of the cap and the base of the distributor.

RBob.

 

Ron,

I drilled a few holes near the top of the cap and facing the firewall so water wouldn't splash into it. I never had an issue that way. My purpose was to dissipate the ionization in the cap not moisture. I agree w RBob, and pulled cap off every so often to inspect and clean. Even having some metal "flakes" on the cap which could cause arching. I'd check for carbon tracks in the cap also. Using an Accel cap made it easier due to the tan coloring of it.

 

The did make a rotor for gm small cap remote coil tbi and tpi to help with moisture acdelco D461 gm 10477219 the bottom of the rotor has fins to help move air and moisture out the bottom of the distributor base vent screens.

 

Have to chuckle, that is wild. A fan on the bottom of the rotor to circulate the air. Who'd had thought!? Thanks for that, it may be a good idea to use that rotor water or not.

The only issue is that the base plate screens do become plugged. More so when dielectric grease is used for a heat sink compound under the ICM.

RBob.

 

interesting concept indeed ...... but would mear circulation help with any mosture .... and to RBob's point, drying of the lub inside the cap .????
Though love seeing ideas outside the "box" .... sortaspeak .....

 

Not sure if it is a misunderstanding or not. The plugging of the vent screens occurs even without the trick fan rotor. The silicone dielectric grease tends to run and spread, and clogs the screens.

This would negate the advantage of water removal via the fan rotor.

I always use the white heat sink compound. Which doesn't run and spread.

RBob.

 

RBob,

As u know that heat sink compound is a MUST for the LT-5 ICM. Those babies are like hens teeth.

 

I think that fan rotor from AC Delco proves they knew of the spark/ionization issue with other then OptiSpark distributors. I don't think it was for moisture as I've run the small cap distributor off road, VERY WET, without issue...

I've never seen one though, cool!