Hei conversion Intermittent start?

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Update:

I ruled out some things tonight. I decided to take Bill's suggestion of a jumper wire, but go several steps further and remove the ignition system from the factory wiring. Ran the necessary jumpers so the coil, dist & hei were hooked up to the appropriate ground/12v. The car fired right up. So now I know those 3 items are not an issue.

So now the plan for tomorrow(if i can find time) is to try and re-integrate the ignition system removing one jumper at a time.

Would've done it tonight, but Side exhaust at 11pm doesnt make the neighbors happy.
 
HEI modules run pretty warm and require a heat sink. The stock gm dist. they were originally designed for was thick aluminum that acted as a heat sink. I see where you said you mounted it to either aluminum of stainless steel but weren't sure exactly what. Aluminum makes a good heat sink but I'm not sure aoubt the properties of stainless. Plus you should use some heat sink compound between the module and mounting block to help transfer the heat. Did you do that? If not, maybe it's overheating and shutting down.
 
An easy way to test if an HEI module is working is to unhook the connecter coming from the pickup, turn on the ignition and lick your fingers and touch them accross the pickup terminals. That will make it fire. Don't worry it's super low current so you won't be shocked.
 
fishy68 said:
HEI modules run pretty warm and require a heat sink. The stock gm dist. they were originally designed for was thick aluminum that acted as a heat sink. I see where you said you mounted it to either aluminum of stainless steel but weren't sure exactly what. Aluminum makes a good heat sink but I'm not sure aoubt the properties of stainless. Plus you should use some heat sink compound between the module and mounting block to help transfer the heat. Did you do that? If not, maybe it's overheating and shutting down.
Click to expand...

I did use a heatsink compound and yeah it does get warm quick when it runs, but prior to the engine running there doesnt seem to be any heat on it.

I was able to get the car to start with the 12v/12vbypass wire earlier today and found that it wouldnt start with the longer dist. pickup wires. Only with the shorter ones i had. Still wont start reliably.(1/10 cranks give/take)

So i'm down to a time limit. If i can get it sorted by wednesday, i'm scrapping the hei for a billet rtr dist. from pertronix/msd/etc
 
magnumdust said:
I did use a heatsink compound and yeah it does get warm quick when it runs, but prior to the engine running there doesnt seem to be any heat on it.

Ok, that rules that out.
Click to expand...

I was able to get the car to start with the 12v/12vbypass wire earlier today and found that it wouldnt start with the longer dist. pickup wires. Only with the shorter ones i had. Still wont start reliably.(1/10 cranks give/take
Click to expand...

You might try twisting the wires coming from the pickup. When I worked on electric forklifts every once in a while we'd run into one doing crazy things and someone discovered by accident that if we twisted the wires coming from the heat sensor it'd straighten it out. We figured it was picking up RF interference. I know it's a different component in your case but a pickup coil can pickup RF so it's possible and an easy test.
 
fishy68 said:
You might try twisting the wires coming from the pickup. When I worked on electric forklifts every once in a while we'd run into one doing crazy things and someone discovered by accident that if we twisted the wires coming from the heat sensor it'd straighten it out. We figured it was picking up RF interference. I know it's a different component in your case but a pickup coil can pickup RF so it's possible and an easy test.
Click to expand...

I believe they are already twisted.(will have to double check tomorrow)
 
fishy68 said:
I see where you said you mounted it to either aluminum of stainless steel but weren't sure exactly what. Aluminum makes a good heat sink but I'm not sure aoubt the properties of stainless.
Click to expand...
Stainless steel is a very poor heat conductor. If you put a 1/2" thick piece on a hot range element, you might wait 15 minutes before you feel any heat at the top.

Twisting wires is a very common method of eliminating pickup from magnetic fields (like coils). The little loop in each twist reverses the polarity picked up, so it averages out to zero with many twists. UTP cable (unshielded twisted pair) is commonly used for ethernet.

You don't need to spend $200 on a new billet distributor to get a good ignition. As mentioned, the Chinese distributor w/ built-in HEI module is only $45 for the small block version, search Steve White Performance on ebay. Or you can buy the same part for $70+ from others (Pro-Comp, ...). Several posts on here evaluating it. The only complaints I read were from people who didn't buy one.
 
Here are some pics of the setup when i first had it setup. Maybe someone can spot something.

First is the mount. Mounted where the original ignition box was.
Next is the bypass splicing.(blue+brown connected at one side, other side goes to hei module.)
3rd is where the brown wire splices and goes to the + side of the coil.
4th is at the coil. It fired up once like this, but i swapped to an e-core, and i think that coil dropped off a bench.(stopped working and failed bench test last night)

mind the odd zip ties, had a bogus theory that maybe clips were arcing across eachother and i didnt have any elect. tape, so i used a few tears of old stuff for a test.

Bill- Only skeptical of those ebay dist. because i'm afraid i'll spend 50 bucks, get it hooked up and i'll be right where i am now.
 

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http://designed2drive.com/

Try using this adaptor.I have it on my Dart now and have zero troubles with it. Quick and easy install.
Where do you have your module mounted? Under the inner fenderwell? I would, if it were me, remove it from there and get it closer to the distributor. All that extra wire is only asking for troubles, plus it is a voltage drop.
 
sorry to hijacking... but i have wery similar broblem whit my HEI.

i just installed hei and new e core coil, but it wont fire. i cheked the new coil by using my old mopar box and it works, but with same connections hei wont fire, cant see any light when using timing light.

I have tried using jumper cable from battery to coil+, nothing...

Can i test the hei module anyway that it is ok? like putting sparkplug directly on coil wire and connecting hei unit two lines that go to dist ?

Does hei need some special spark plug wires to work??

and can see does it fire by putting timing light to coil to dist wire?

AND i brobably have some not orginal distributor. it is electronic but can i test that it gives good signal to hei module? my mopar box is blue not orange if that tells anything
 
gliderider06 said:
http://designed2drive.com/

Try using this adaptor.I have it on my Dart now and have zero troubles with it. Quick and easy install.
Where do you have your module mounted? Under the inner fenderwell? I would, if it were me, remove it from there and get it closer to the distributor. All that extra wire is only asking for troubles, plus it is a voltage drop.
Click to expand...

Using this bracket, do you get a solid ground for the HEI module with the heat grease needed between it and the distributor base?
 
Do you have a tach hooked up? I had a tach fail that somehow grounded the - side of the coil resulting in no run/bad run condition.
 
FWIW, I had 2 issues with my HEI conversions (3 of them).

1. swapped the pickup polarity from the distributor - caused a failed ignition module 2 x, and erratic timing another. It does matter.

2. Low voltage to the module. Caused intermittent starts. These HEI module require high voltage to run, (11+, in my experience), whereas the Mopar module requires 5+. I was losing a good bit of voltage through the bulkhead connectors, ignition switch, Ammeter, etc. While you may be getting 12+ volts when the keyed ignition is switched to the "run" position, when you engage the starter, it can easily dip below 12 volts, even into the 9's for an old battery. Thats why the Mopar ignition bypasses the Ballast resitior in the "crank" mode, and returns to that ballast circuit in the "run" mode. I installed a relay, switch on by the normal "run/start" voltage from the ignition, and hot wired directly to the started relay block. This helps eliminate the additional voltage drop through the bulkhead, etc, gaining an additional .2 to .5 volts. Problem solved for me!
 
What is this connection? It looks unshielded and uninsulated?

magnumdust said:
Here are some pics of the setup when i first had it setup. Maybe someone can spot something.

First is the mount. Mounted where the original ignition box was.
Next is the bypass splicing.(blue+brown connected at one side, other side goes to hei module.)
3rd is where the brown wire splices and goes to the + side of the coil.
4th is at the coil. It fired up once like this, but i swapped to an e-core, and i think that coil dropped off a bench.(stopped working and failed bench test last night)

mind the odd zip ties, had a bogus theory that maybe clips were arcing across eachother and i didnt have any elect. tape, so i used a few tears of old stuff for a test.

Bill- Only skeptical of those ebay dist. because i'm afraid i'll spend 50 bucks, get it hooked up and i'll be right where i am now.
Click to expand...
 

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Here is the simplest diagram possible. Make sure the wires from the distributor to the module are correctly connected, it does matter!

The module is mounted, and thus grounded, to the car body. Just like the original mopar box, it won't run without a good ground!

Hook the hot wire directly to the battery, as shown, completely bypassing the ignition and ballast circuit. Do not use any of the original mopar wires, exept the plug coming off of the distributor. Use new wires between the coild and the HEI module, and new wires from the distributor connector to the HEI. A new wire jumper to the battery positive as well. BTW, the engine won't stop when you switch off the ignition in this configuration, you will have to unplug the hot wire from the battery.

If it won't start like this, there are 5 possible solutions, as far as I can see:

1. You have a bad coil

2. You have a bad distributor:
a. Reluctor is hitting the pickup, and/or is magnetized
b. Reluctor/pickup Air Gap is wrong
c. Pickup is bad

3. You have a broken wire or a bad connector - I had an intermitent one on the original 2 prong connector to the distributor.

4. You have a bad module

5. You are not following the schematic.

If it runs fine with the Mopar box, and a switch back and forth to the HEI won't run, you can probably eliminate 1 & 2, and maybe 3.
 

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jimmyray said:
What is this connection? It looks unshielded and uninsulated?
Click to expand...

Just unwrapped that for a picture when i was chasing wires. That is the brown 12v switched or bypass wire(like i said above, not totally sure which is which) and that connection is the spliced in wire goes to the + side of the coil. I re-wrapped it after the picture.
 
magnumdust said:
Just unwrapped that for a picture when i was chasing wires. That is the brown 12v switched or bypass wire(like i said above, not totally sure which is which) and that connection is the spliced in wire goes to the + side of the coil. I re-wrapped it after the picture.
Click to expand...

Just checking... :D
 
jimmyray said:
Here is the simplest diagram possible. Make sure the wires from the distributor to the module are correctly connected, it does matter!

The module is mounted, and thus grounded, to the car body. Just like the original mopar box, it won't run without a good ground!

Hook the hot wire directly to the battery, as shown, completely bypassing the ignition and ballast circuit. Do not use any of the original mopar wires, exept the plug coming off of the distributor. Use new wires between the coild and the HEI module, and new wires from the distributor connector to the HEI. A new wire jumper to the battery positive as well. BTW, the engine won't stop when you switch off the ignition in this configuration, you will have to unplug the hot wire from the battery.

I did that and it was really the only way i could get the car to start. Semi-reliably though

If it won't start like this, there are 5 possible solutions, as far as I can see:

1. You have a bad coil
Using a brand new coil(not in the pics)

2. You have a bad distributor:
a. Reluctor is hitting the pickup, and/or is magnetized
b. Reluctor/pickup Air Gap is wrong
c. Pickup is bad
Would this be an issue given that the car was driven with no starting issues on that same distributor? Its a "new" parts store distributor with less than 1000 miles on it

3. You have a broken wire or a bad connector - I had an intermitent one on the original 2 prong connector to the distributor.
possibly, but i have no idea how to track it down. I did use another 2 prong connector i have.(shorter one) and that did help starting, but didnt solving anything

4. You have a bad module
I have used two hei modules. Same results

5. You are not following the schematic.
I'm definitely follow the schematics

If it runs fine with the Mopar box, and a switch back and forth to the HEI won't run, you can probably eliminate 1 & 2, and maybe 3.
Unfortunately I can't put the old ignition back in place
Click to expand...


Updated w/ bold.
 
magnumdust said:
Updated w/ bold.
Click to expand...

I did that and it was really the only way i could get the car to start. Semi-reliably though

Did you pull the wiring from the coil and module, and run a hot wire to both, or in series, as shown in the illustration?

Would this be an issue given that the car was driven with no starting issues on that same distributor? Its a "new" parts store distributor with less than 1000 miles on it

Could be. I would check the air gap to be sure. Did you remove the distributor when you installed the system? Timing off? FWIW, I cut the plug out completely, and soldered wires to the distributor leads, and connected directly to the HEI. About 1 foot wire total for each lead. Are you using the original pickup wires from the dist to the HEI?

Looking at the HEI mount, running a ground wire fro the bolt (under the nut, touching metal sleeve on HEI) to the body would eliminate the bad ground potential.

Do you have a multi-meter? Check voltage to coil with ignition in "run" position. Also check it to the Module.

Can you take a pic of the entire engine bay, showing where everything is, and how it is wired? Also, get a pic of the "hotwired" wiring.

Are you 100% sure the distributor wire to the HEI are correct? They are easy to swap, and will cause this exact problem. I learned that the hard way!!! Maybe just swap those to wires, and try it?
 
jimmyray said:
Did you pull the wiring from the coil and module, and run a hot wire to both, or in series, as shown in the illustration?

I made 4 test leads. One lead went from the + on coil to the + side of the battery. One was ground straight from that hei bracket/mounting nut to the neg side of the battery. Then two more leads from the hei to the pos and neg sides of the coil. It started up like this

Could be. I would check the air gap to be sure. Did you remove the distributor when you installed the system? Timing off? FWIW, I cut the plug out completely, and soldered wires to the distributor leads, and connected directly to the HEI. About 1 foot wire total for each lead. Are you using the original pickup wires from the dist to the HEI?

I didnt remove the distributor and i know timing isnt off. The original pickup wires are being used.

Looking at the HEI mount, running a ground wire fro the bolt (under the nut, touching metal sleeve on HEI) to the body would eliminate the bad ground potential.

As stated above, used a test lead to completely eliminate that possibility, but it seemed to have no effect.

Do you have a multi-meter? Check voltage to coil with ignition in "run" position. Also check it to the Module.

I'll double check that when i get a chance

Can you take a pic of the entire engine bay, showing where everything is, and how it is wired? Also, get a pic of the "hotwired" wiring.

I'll see what i can do there. I have the hei unit out of the car at the moment. Did a lot of testing yesterday and got too frustrated to put it back the way i had it

Are you 100% sure the distributor wire to the HEI are correct? They are easy to swap, and will cause this exact problem. I learned that the hard way!!! Maybe just swap those to wires, and try it?

Yep, tried swapping them just in case, no change.
Click to expand...

Bold for answers(just seems easier when addressing specific questions)
 
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