HEI conversion issues

[TylerW]

Guys:

I built one of my HEI conversions for the Dart, using a factory GM coil, module and the factory Mopar distributor.

Having a strange problem: The engine will not fire when the key is in START position. As soon as you let off, it runs for a second or two, then quits.

There is nothing going through the ballast resistor anymore, so that is NOT the issue. These run off 12v directly to them.

I did double check to make sure the voltage was there during crank and it is.

Any thoughts are welcome.

 

[crackedback]

You likely need to pigtail in the start hot wire. Their are two circuits feeding the coil on mopars, one in start, another in run. Blue and Brown wires come to mind in most cases. One would have hooked to the downstream side of your old ballast resistor.

 

[67Dart273]

Need more details of how you wired this up....................

 

[tekslk]

I agree with cracked I think I remember thats how I did mine when we got rid of the ballast.

 

[TylerW]

Need more details of how you wired this up....................

I built it as stand-alone, the same as I did my D150 which worked fine.

I used a coil/module combo from a '97 Vortec Blazer. I did use a regular 4-pin module. I use those particular versions because they have the coil bracket with the module heat sink integrated with it, very neat and tidy.

All I do to wire them up is run a 12v key-on source, because that's all that an HEI needs unless I'm mistaken somehow. I do ground them well.

In this case I used the 12v feed for the choke, since I'm using an Edelbrock carb that doesn't need the choke controller.

I thought at first that that circuit might go dead in the start position, but according to the meter it doesn't.

I'm a little confused about the issues regarding the ballast resistor and coil wiring in these instances, because the way I do it, all that is completely bypassed and not used anymore.

I know ideally the HEI needs battery voltage to keep from burning up modules, using a relay, but this is just temporary to get it running. The reason I say that is because by the time the power has made it's way around to the choke, it's lost about a volt.

The mopar ignition system is all still intact, so I may reconnect it tomorrow and see what happens. It didn't work at ALL when I tried it the first time but perhaps I can solve that.

 

[tekslk]

Do a search on this sight for hei. Trailbeast makes a kit with online instructions, he may chime in to help you, he certainly did me.

 

[67Dart273]

4-pin module.................... run a 12v key-on source......................... I used the 12v feed for the choke, ..................I thought at first that that circuit might go dead in the start position, but according to the meter it doesn't.

I'm a little confused about the issues regarding the ballast resistor and coil wiring in these instances, because the way I do it, all that is completely bypassed and not used anymore..

What kind of vehicle? MOST of the 60's --early 70's Mopars IGN1 / run circuits go dead in the "start" position, and you must incorporate the brown IGN2, or "bypass" circuit, which is why you tie the original ballast stuff together

by the time the power has made it's way around to the choke, it's lost about a volt..

This should NOT be true, and may be a clue to the problem, and in fact is why I'm always "ranting and raving" about voltage drop in these old harnesses.

The FACT is that there is ONLY ONE switched 12V line in these cars which comes on with the key in the "run" position. (Why we need to know what you are working on................)

The 70/ later and 73/ later with seat belt, smog, etc cars are fed off this "run" buss:

"IGN1" comes out of the bulkhead connector, branches off, and feeds:

ignition system "run"

regulator "IGN" terminal

alternator field (blue)

idle solenoid if used

distributor retard solenoid if used

electric choke if used

on some cars maybe one or two other smog doo--dads.

If you are losing a whole volt from battery YOU HAVE PROBLEMS and need to find out WHY

The circuit path on an un--modified factory harness is:

battery---fuse link---bulkhead connector---ammeter circuit---in harness splice---ignition switch connector---through the switch---back out the switch connector---back out the bulkhead connector (ignition run)---and branched off to the list above

 

[TrailBeast]

Is it possible that the distributor wires are backwards?

Also try going directly to the battery for a temp power source for your coil so you can eliminate a low power issue.

If this does not work then you may have a bad ECU.

As far as using the choke power wire for your coil power, the choke is a directly grounded circuit (running through a bimetal element)
It may be dropping the power to low. (Again, jumping right to battery positive should tell if this is the problem)