I just installed an HEI on my 66 Malibu. In addition, I installed a new engine harness from K&M. Since the harness I was replacing was about 5% original with 18 splices, I guessed on the wiring to the solenoid. I took the purple to the lug on the driver's side and the pink to the lug on the passenger's side (center lug from battery is above) since that's the way it appeared to be in the service manual.

The engine started fine, but would not shut off. I checked the wire going to the HEI and it had 12 volts with the ignition off. I noticed that there are two wires going to the HEI, one from the fuse box and the other (the pink one) from the solenoid. If I were to hook the wires up backwards to the solenoid, would it cause something like this?

Right now I have the battery disconnected till I figure this out.

Thanks,
Dave

Right now I have the battery disconnected till I figure this out.
Good, as leaving it connected will drain the battery. Check to see which terminal the HEI is plugged in at the fuse box. If its plugged into the BAT terminal, that has power all the time. It should be plugged the IGN terminal, which only has power when key is on.

It needs to be connected to a terminal/circuit which has power during the start and run position for the key.

The engine doesn't start until I turn the key to the start position. It seems if it were wired wrong on the ignition, the starter would always be going as long as the HEI was seeing 12 volts?

It seems as if the 12 volts is coming from the solenoid.

Dave...as Undee said...check as to where it is connected to the fuse panel!
"BAT" terminal is live all the time(distributor would have 12v constantly)
"IGN" terminal is controlled by the ignition switch(12v to distributor in
"ON" position..0v when in "OFF" position).
Starter solenoid is not part of the equation.

The starter and the HEI are on different circuits anyway. You are right that if the HEI and the starter were on the same circuit and there was constant 12 volts then it would continuiously turn over. But what has happened is that the starter is connected correctly and the HEI is not seeing a switched power. So you need to find a circuit from the fuse panel where there is 12 volts only in the ON and Start position.

So... what is firing up the starter then? Is the - side tied to the ignition too and that what the start signal is provided to?

This is very odd because the wiring harness in the dash is also new. I have not had a single problem with any of the K&M harnesses and the ignition switch all the way to the HEI/Starter is all pre-wired.

Doh.. minor acronym confusion. The harnesses are made by M&H.

Dave,
The problem is the pink wire from the solonoid. You do not need it for an HEI installation. It was designed to give the point ignition full battery voltage during cranking, so you would have a little extra spark voltage. Once the engine started, the pink wire went dead and the ignition was fed through the resistor wire. Just get rid of the pink wire and you should be ok. The strange thing is, it really should not be hot except when the starter is engaged, so something might be wrong in the solonoid too. The purple wire should go to the "S" terminal on the solonoid. That is all you need with your setup.

I went with the solenoid theory because it's one of the few opportunities I, personally, had to mess things up. If it wasn't me it was the harness guys that have been doing these since I've owned late model chevies (10 years now). It turns out, there was another opportunity I had. I had removed the clock and installed the guage upgrade kit to see if I could get it to work. I had, inadvertantly, plugged the clock plug into the water temp plug... one of which has a nifty little 12v (bat) power supply and the other has a a pink wire connecting to it.

Everything is fine now.