MrSeKrEt

I found this on a Truck board. Has anyone done this? Does anyone thing this is possible?

"I had a problem with my 86 C20 305-H engine. It could start and run fine and just suddenly die out, sometimes start right back up or take a couple hours to get restarted. After several weeks of this nonsense (and getting very good at getting those half turn dist. cap latches off), I did some checking. There is a power feed to the spark control unit under the dash that comes off of the pink (hot) wire to the distributor. The pink wire clips into the connector for the feed, which in turn clips into the dist. cap. What had happened was the feed for the Spark Control was shorting out somewhere, killing the spark. I talked to some Chevy mechanics at my dealer about this and they told me how to bypass the spark control computer and keep the original distributor, something they claim is done quite often.
First thing to do is unhook the spark control computer lead from the pink wire and hook the pink wire directly to the dist. cap. Make sure you plug it into the cap at the BAT terminal. The second thing is to locate the 4 wire connector that feeds into the ignition module. There's a brown (D), green (C), white (B), and black (A) wire there. The letters in () are on the black clip that the wires come out of. You cut the green (C) and black (A) wires between this clip and where they go into the distributor. Then all you need to do is solder the 2 cut leads from the dist/ignition module together, i.e. the green and black ones, (make sure to tape the exposed wires) and now your HEI distributor will function just as a pre ESC model does. I did this and it has been running fine for well over a year now. "

five7kid

iTrader: (14)

I have an '84 full size conversion van that came with a 305 "H" (LG4). It's kind of a wierd setup, in that it has a computer, a flat 4-wire connector to the distributor, but also vacuum/mechanical advance. The carb is not computer controlled.

My sister's family had it before us. It was always a dog, the dealer was always working on it. The 305 finally died from overstress, and the dealer put in a Goodwrench 350 for them.

When we got the vehicle 9,000 miles later, the 4-wire connector was disconnected and they had used an in-line solderless splice to tie those two wires together. I figured that was nuts, took the splice out, and hooked the 4-wire back up. It didn't make any difference in how it ran, but I figured it had to be better to let the computer do what it is supposed to do (which I don't know exactly what it is in this case), rather than this "band aid".

Frankly, in this case, it appears the dealer tried something they had "heard about" to try to solve a problem that didn't involve the computer at all (tired engine that had been neglected by the original owner).

My point is, the truck systems in that era were different than our cars, so the message is, "Forget it." If the computer isn't there, you need vacuum and mechanical advance in order for the distributor to "function just as a pre ESC model does". The trucks had that, our cars do not.