HEI Problem???

[Mustard Mobile]

Hey Guys,

I got the HEI in and after some fiddling I got the truck to run. It was running great had it in time and was proceeding to hook up the vacume line to the dist and it died. So I hooked every thing up and tried to start it up and it wouldn't go. So I unhooked the vac line to the distributer and got it going again with a little gas poured down the carb and it ran like junk. So I started to fiddle with the timing again and got it going no where near where it was earlier. I cant seem to get it back to where it was. I haven't pulled the dist yet since it was running so great in the present position. Any Ideas??????


thanks,

andy

[Zkast]

Sounds like you may have broken wires from the pickup coil. When the vacuum advance is connected it pulls the pickup coil counterclockwise, if there is a break in the wires it will die.

To check for this, pull the cap and rotor. Gently move the wires around from the pickup coil to the module and look for any open insulation area's or see if the wire completly breaks off.

[Mustard Mobile]

I checked every thing out before I put every thing together I dont remember seeing any breaks on the wires. Very little vacume is coming from the carb through that port. I would think there would be more. It sure is irritating I finally got the thing running awsome and then it falls on its face with out me really touching it.

[JimKshortstep4x4]

I agree with Zkast, the pick up coil has to be defective with what you are describing. If you have not tested it yet, isolate the coil and test with an ohm meter. It should read 750-800 ohms. If you move the connection wires while testing, the ohm's should stay the same.

Jim

[Mustard Mobile]

I work in a parts house and I tested the pick up against a new one and did get those ratings before I put it in. I will try to wiggle the wires later today. Any other ideas??
andy

[palallin]

Are the weights/springs on the mechanical advance gummed up or jammed? It's possible, I suppose, that fiddling with the vacuum advance might have pulled the mechanic parts out of line.

[wcdrake]

Just hooking up the vacuum advance at an idle should not effect the engine if at all as long as your connected to the correct port on the carb. The correct port is ususally near the top where the vacuum signal is low at an idle. It sounds like you are pulling your vacuum from a lower port on your carb if your engine dies after connecting the vacuum advance hose. Especially if it is running good before. Is this the case? Also, when you disconnected this vacuum advabce line, did you plug the end of the hose?

[bigjimzlll]

lol...I do not agree with the "correct port" ..most performance ignition men will tell you to hook in the full manifold vacuum port, and limit the vacuum advance to 10 degrees, this allows the motor to run at 20-22 degrees at idle (right where most like it) then at cruise the mechanical advance is all in at 3200 rpm..(32-34 degrees).. with the timed port, at 3200 rpm you can have 10 inital+22 deg. mechanical+15 degrees vacuum=47 degrees...not where I want my 10-1 c/r motor running..oh well sorry for the tirade...about the post...it sounds like you have some gummed up weights and/or broken wire--

[Mustard Mobile]

Ohm meter read 830 and stayed steady while jiggling it around. The wieghts and springs are clean. The port I am using is the one that the factory used because it still has the metal line and I know its never been changed. It fired right up with some chugging and when I ran around to fiddle with the distributer I got it going awsome again. Then I hooked up the hoses again and it died. I unhooked every thing again and its not going again. In fact it backfired out the carb with flames. If it was 180 out I would think it wouldn't run except for lots of backfireing and lots of smoke ( at least that is my experience of the past).

What I know of the distributer is a friend gave it to me a couple of years ago out of his truck when he up graded (early 70's). It had a automatic instead of a manual like mine. Maybe thats it. I am quickly running out of options and its about to snow.

any further ideas??

[71GMC_3/4T]

A friend of mine had a late 70's Chevy PU with HEI. He brought it over one day and asked me to take a look at it. It started and ran fine, but when he stood on it, it would buck and snort something fierce. It turned out to be the condenser inside the distributor. The wire had flexed several million times with the vac advance and broken the wire inside the insulation. When I pulled on the wire, it stretched the insulation at the point where the wire was broken inside. New condenser = problem solved.

Snow???!! Well, I guess it's getting to be that time of year again... WTF happened to summer?

[67shortie]

My big block ran like this when I was only one tooth off installing the distributor. Have you put a timing light to it? I had to move the distributor in a major way to get the enging to even idle, this may be the culprit.
When you say the vacuum advance is hooked up, the thing runs like crap. What could be happening is when the hose is installed, the timing will move even more out of whack causing the engine to stall, especially if the hose is connected to a port with full vacuum. What you should try is keep the line unhooked, put a timing light to the engine and see where you are sitting. If you are within spec's, something might be wrong with the advance plate, or the vacuum pod itself (broken diaphram causing major leak) Also, dumb question, do you have 12 volts of power going to the coil? If you don't the HEI will not work properly at all.

Keep us posted.

[Mustard Mobile]

Thanks all..

Yes that was one of the first things I checked I do have 12 to 13 volts to the coil.

I will check the condenser and restab the dist. It may be off by one tooth. I am at an end.

Just had the thing running like a top and went to pull out and it died. I even had the dist vac attached with it running good.

cant wait untill I can start the electric car conversion.....

[Mustard Mobile]

I am ready to shoot the thing. Got it going again....same results....What will happen if I don't run the Vac advance???

[bigjimzlll]

not a thing...just advance the initial timing to 18 degrees...now i wouldnt run it like this all the time, but for testing its ok

[JimKshortstep4x4]

Your problem sure sounds frustrating! Whatever is causing this, (broken wire, loss of connection or whatever) will eventually fail.

Is there anyone close by that has a distributor machine that could check it out for you? (If you were closer to Michigan, I could do it for you with my old Sun machine).

I hope that you will let us know what you find out on this problem
(if you are able to isolate it)

Good luck!

Jim