Hi everyone,

I did the HEI conversion about a month ago on my 85 D100. The engine is out of a 69 Barracuda so I got a distributor with the electronic pickup (Cardone 843690), Delphi DS10071 module, and a Flame thrower 3 coil (0.32 ohm).
It idled and ran adequately with the old points and the rest of the old system. (the wiring harness is hacked up by previous owner, 85 with a 69 engine, lots of extra wires)

Now it idles like it has an intermittent miss. It has a near constant but slight stutter while driving. A lot of throttle with low rpm is the worst situation. Light throttle at higher rpm is almost unnoticeable. I've been tweeking, tuning, etc.. for weeks now and nothing seems to help. I've read the install thread, all the posts, watched youtube. Nothing is helping.


Installation stuff:
I know I have the two wires from the distributor correct. I did switch them as a test and it was obviously better one way.
I have a relay to the battery for power. I temporarily went directly to the battery for testing and it still runs poorly.
I mounted the module with an aluminum heat sink on one of the voltage regulator bolts right behind the engine with star washers and then later with an additional ground wire from the module to the battery ground.
.045 spark plug gap

Attempted tuning/changes:
Autozone module = no change
The more timing advance I give it the more it likes it. I'm currently at 25 deg. before TDC with no vac or weight advance. Its not pinging and goes way up there with the vacuum connected. (I made a table of the distributor vac advance and what it does when) I've messed with the vac canister and had it at multiple settings. The more advance the better but still doesn't run smooth. Still shakes the hood at idle.
This amount of advance baffles me. I did nothing other than "upgrade" to the HEI and it almost acts like I set the timing chain wrong. At least as far as the timing setting goes.
It has a reasonable amount of power. Just the holley 1 brrl.

My Javelin has a pertronix system, I will switch the coils tomorrow and see if something changes.

Has anyone had a situation like this or know of something else to try? I was going to do this to my son's 75 Dart but I want to make sure this one works good before I tear his up.

Yoiks. Something is very wrong. Can't say what, from all the way over here, but:

Cardone's stuff is notorious garbage.

Try a coil meant for use with HEI, as described in the HEI upgrade article

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Too many people who were born on third base actually believe they've hit a triple.

Are the pickup wires switched on the HEI module? Easy swap to check if it makes any difference.

If you are really at 25 BTDC it should barely crank over and should ping like crazy.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Update.
Just tried using the oem distributor out of my son's 75 dart with the same results.

Also tried the pertronix coil from my Javelin with the same results.

Just sourced the exact coil in the write up. That's going on next.

The distributor wires to the module are correct.

There isn't any indication in the std prod FD478 coil or the S539 pigtail about which side is positive or negative.

There are the two green wires on one side and a red on the other.

Okay, so it's not the coil, it's not the distributor, it's not the power supply, and, if it is otherwise operating more or less normally (starts, runs, idles, accelerates), it's unlikely to be the carburetor or the fuel supply.

Sooo... What Did You Do?

You must have moved, nudged, adjusted, changed, replaced, or otherwise messed with something in the course of installing this system.
Something being wrong with the ignition timing would seem to be most likely, in terms of replacing distributors, and having a car that runs, but doesn't run well, and has unusual timing behavior under the timing light.

There's probably no chance that the timing chain has jumped a tooth... Is there...?

Have you tried disconnecting one spark plug wire at a time, to see whether one of them doesn't affect the problem, but the others do?
This would show a problem with once cylinder (or it's spark plug, wire, distributor cap terminal, etc.).

Do you have an advance timing light, or just a "regular" one?
Do you have access to an automotive oscilloscope ("Sun machine")?
Do you have the patience / dexterity to mark off the vibration damper to be able to read "off-scale" timing numbers?
Have you tried checking your timing on each of the other cylinders? (Silly exercise, I know, but has a small chance of contributing a few data points).
Any of these can help you find more information, which may help you to determine whether your timing is too far off.

There's a good chance that this is one of those problems that if you had an experienced Slant-6 mechanic there, he would just say, "There's your problem," but through the interwebs, it's a sticky wicket.

– Eric

I find it hard to believe that you are at 25 BTDC. The first thing I would do is Use a piston stop and verify TDC on the timing marks. Then verify the timing light is correct.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

The std prod coil didn't work either.

I have the timing set at 1-2 btdc. It did run at 25 but I'm not going to try problem solving in that situation.

My timing light does have an advance dial and I compared it to another just to check it.

The timing mark is at tdc, done with a piston stop. Valve timing I haven't checked yet... jumped a tooth.
This doesn't seem likely as it has adequate power. Just jittery.

The only things left I can think of is the voltage regulator and/or the alternator.

You're barking up the wrong tree, but if you want to be sure, just put a voltmeter across the power feed for the HEI module.

You won't see any appreciable variation, and certainly none that is in sync with your problem.

But no harm in giving it a shot, just to be able to say you've ruled it out.

You've checked all of your plugs, wires, cap, etc., right?

I remember once I had a crazy intermittent crappy-running problem on a '71 Skylark.
Damned car started instantly and idled smooth as glass, drove great, but started to break up as soon as you gave it some gas, worse if you really got on it.
I went through all the usual stuff, carb, fuel pump, fuel lines, points, condenser, timing, coil. Nothing was bad.
Finally put it on a Sun machine. Two cylinders would begin to fire, then the voltage would clip.
I had two bad spark plug wires, which had carbonized trails where the current would leak out when the voltage got to a certain level. Below that, they were fine, exceed the voltage, and they drained off.
What causes higher resistance and the need for higher voltage to initiate the spark? Higher combustion chamber pressure and heat, ie: acceleration.
Step on the gas, need for voltage increases, exceeds carbon trail's threshold, current drains away, no spark, car runs crappy.
Let up on gas, less voltage needed for spark, spark occurs before leakage threshold, car purrs like a kitten.

I'm not saying that this is your problem, but it could be something odd like this.

– Eric

Your Skylark sounds like what this is doing. Low rpm with alot of throttle is really bad.

3 different caps and rotors, even mixed and matched them. 2 sets of wires, fancy Denzo and the ones from the Dart. Neither acted differently.

Any suggested plugs? I'll get some magnacore wires.

Many years ago, I changed plugs on my race car (routine maint). Took out Autolites, and put in Champions. Ran 2 race dates with no problems, but on the 3rd, started getting a down track misfire. Could not find the problem. Finally decided to change out the plugs to a used set of Autolites I had with me. The misfire went away. Just to confirm the problem was the plugs (Nothing was visible), reinstalled the Champions, and the misfire was back. I sent the plugs to Champion describing the problem. Champion got back to me and said there was nothing wrong with the plugs (and didn't even return the plugs or replace them). I haven't put Champions in an engine since then (1964).
PS: On my slants, I like to run NGK (first choice) or Autolite.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

Magnacor wires are a pain to get quick.

Anyone have an alternative worthwhile?

+1 what Charlie said regarding Champions and from the same time frame as well.

Fred

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I've got the ngk plugs to install. Im going to do a compression test.

Is 175 or more considered good? Thoughts?