Hei conversion Intermittent start?

[BillGrissom]

You can buy those relay pigtails on ebay with or without relay. I bought a box of 10. For more current, upgrade the 2 main wires. You can find the relays (30 or 40 A) even at Radio Shack. Maybe even easier, you can often find a "fan relay" w/ harness on ebay. I bought 2 for $15 ea in a GM shrink package. They were part of a dealer add-on fan upgrade/recall, maybe for AZ, and hit the surplus market. The relay is slightly different (shrouded base like some Mopar ones, but same terminals - 85,86,30,87,87a).

 

[Johnny Dart]

So what was wrong with your original factory ignition ?
I'm stumped on how this is better......:scratch:

 

[replicaracer43]

so what was wrong with your original factory ignition ?
I'm stumped on how this is better......:scratch:

x2

 

[magnumdust]

So what was wrong with your original factory ignition ?
I'm stumped on how this is better......:scratch:

Well, the big push has to do with the efi kit that's been sitting in my living room for the last two months. The kit needs a solid 12v source while cranking and the coil is a suggested easy hook up location(instructions and forums), but that doesnt work well with the factory mopar ignition.

That's how its better for me.

 

[gliderider06]

I have done 2 different cars with the http://designed2drive.com/ conversions using the Summit "E" coil and had no problems with it. The hardest thing to do was mount the coil. I think you need to take everything apart and start over again, slowly following the given wiring diagrams and a FACTORY wiring diagram to straighten and clean up your wiring. Do what everyone has suggested. Clean the bulkhead connector, add a ground from the battery to the chassis and all the other suggestions. This conversion at best, should have only taken a few hours.

 

[replicaracer43]

Well, the big push has to do with the efi kit that's been sitting in my living room for the last two months. The kit needs a solid 12v source while cranking and the coil is a suggested easy hook up location(instructions and forums), but that doesnt work well with the factory mopar ignition.

That's how its better for me.

You do understand, that the ballest resistor only steps down the voltage to protect the coil, right? you could eliminate that, and get a coil made to be used without a resistor, problem solved... Those GM modules fail quite often, but perhaps the ones I have been replacing have been of china origin..........

 

[replicaracer43]

And ditto on the checking the bulkhead connection, and the basic integrity of your electrical system....Get the basics figured out 100% first

 

[fishy68]

But I would not get sidetracked until you get this cleaned up some. I would do following: Get the module mounted, and get the distributor pickup wire cleaned up, shortened if possible, and TWISTED. DRESS the distributor wire along the firewall which adds some SHIELDING affect, rather than dangling it out into thin air

Um, you have seen the several times where i posted that the wiring looks this way because of testing? I get the feeling you've missed that.

I understand your just testing it but think your missing the point that the whole problem could be just because of the sloppy wiring. Like me and others mentioned the wires from the pickup coil should be twisted. That means all the time, even while testing, because at any time they can attract RF that will screw up the signal. And the piece of metal you have the module screwed to is not enough heat sink, even for test purposes. Those modules generate a fair amount of heat pretty quickly that needs displaced.

 

[KitCarlson]

I understand your just testing it but think your missing the point that the whole problem could be just because of the sloppy wiring.

x100

 

[BillGrissom]

x3 That is why we like photos. What people describe and what the photos show often differ. I have seen it the other way too, where we were imagining a ratty engine bay and photos show it to be pristine.

 

[magnumdust]

oh yes, that's my problem, messy wiring, and not anything else because of course i purposely went for a sloppy install. Because surely it wasnt that I had a clean install *THAT DIDNT EFFING WORK!!!!!!!!!!!!!!!!!!!!!!!!!!!* and then wiring got messy for testing purposes.

So here is tonights unhappy little clusterfuck.

-Bought a 4pin 40amp SPDT relay. Wired it up per instructions.
-Recharged the battery. 12.5v at rest, 11.5v cranking.(showing 11.5 at the B tab on the hei model while crankng)

Unsurprisingly, this pile of crap refused to start yet again.

 

[fishy68]

You can get sarcastic if you like but it sure doesn't help flaming the guys giving up their time to try to help. I was only trying to help and thought I said it in a civil manner. Sorry I ruffled your feathers. Won't happen again, guaranteed

 

[BillGrissom]

Sorry to pile on, but you did say several times that you twisted the pickup wires, which many people suggested (one even saying that was his problem), and then your photos show totally different. Instead of just endlessly spinning the engine, backup to basics as many suggested. Remove the distributor and spin it by hand while looking for a spark across a gap you carefully arranged on the coil output wire (don't go thru the distributor cap). You have too many variables in the equation as is.

 

[KitCarlson]

Sorry, but I lost it when I saw wiring setup laying on top the plug wires and the coil wire laying on the fender.

It is possible now that the HEI has been damaged. Failure could be caused by insufficient heat sink, open circuit sparking or miss-connection.

When cranking timing reference pulses are irregular as the starter motor speed varied with engine compression. The HEI module extends dwell and is a current limit mode. This mode dissipates the most heat. When the engine is running, the dwell timing is controlled to charge the coil without going into current limit. I am guessing that a flate plate heatsink made of aluminum need to be about 1/4 thick and 2 x 4". It might work with less if it is bolted to the body in a cool place.

Wiring is important! The pickup side of the HEI receives signals from the distributor of only a few volts peak to peak when cranking, and they will be much higher at high RPM. Polarity matters, and short twisted leads are essential to prevent false triggers. A false trigger keeps ignition busy, so spark cannot be provided when desired.

Working with electricity is predictable. It involves not only correct connections, but things in correct physical placement and proximity to other sources. While things like plug wire have insulation for electric fields, there are magnetic fields that radiate.

Maxwell's Equations are helpful for those who wish to know more about electromagnetic field theory.

 

[magnumdust]

Sorry, but I lost it when I saw wiring setup laying on top the plug wires and the coil wire laying on the fender.

It is possible now that the HEI has been damaged. Failure could be caused by insufficient heat sink, open circuit sparking or miss-connection.

When cranking timing reference pulses are irregular as the starter motor speed varied with engine compression. The HEI module extends dwell and is a current limit mode. This mode dissipates the most heat. When the engine is running, the dwell timing is controlled to charge the coil without going into current limit. I am guessing that a flate plate heatsink made of aluminum need to be about 1/4 thick and 2 x 4". It might work with less if it is bolted to the body in a cool place.

Wiring is important! The pickup side of the HEI receives signals from the distributor of only a few volts peak to peak when cranking, and they will be much higher at high RPM. Polarity matters, and short twisted leads are essential to prevent false triggers. A false trigger keeps ignition busy, so spark cannot be provided when desired.

Working with electricity is predictable. It involves not only correct connections, but things in correct physical placement and proximity to other sources. While things like plug wire have insulation for electric fields, there are magnetic fields that radiate.

Maxwell's Equations are helpful for those who wish to know more about electromagnetic field theory.

Sorry if i pissed off anyone. I just "hit the wall" with this suppose to be simple mod and the "messy wiring" bit set me off.

Anyhow, got a late start today(school til 1pm) and tried a few things today. I'm just about on my last leg with this ignition system and just about ready to put it back to stock and send the car packing.(New mopar ignition harness is now sitting in my place, tempting me)

Started with trying to eliminate potential trouble spots and picked up an accel superstock 12v coil(incase that big ugly e-coil is not working quite right) and picked up a BWS hei module while i was at it. Then went by Ace hardware and grabbed some aluminum plate to cut down for a bracket. Cut down the metal and made a simple bracket.

They didn't have terribly thick aluminum plate(.063), so hopefully the size/location will account for enough heat dissipation. Then I cleaned up the wiring a bit. I'm still gonna change the relay wiring out for a pigtail plug if/when i finally get the system working. I couldn't seem to find a pigtail locally.

In case the pic doesnt clearly show it, yes the dist. pickup wires are twisted. I twisted them and then put two pieces of shrink wrap at each end to hold them in place.

By the time i got all this together it was getting dark, so i couldnt do much else. For S&G's I tried starting it(of course nothing) and then thought to yank the dist. cap and rotor to see if they look worn. The rotor looks a little rough, not sure on the cap.

Next week i'll be doing what bill suggested and pull the dist. to rotate it manually for spark.

 

[jimmyray]

The cap is most likely not the issue. The HEI voltage will jump across it.

Check 3 things and let us know:

1. Unplug the wire from the distributor to the HEI module, and connect your multi-meter to the two wire, in DC millivolt mode (200 mV or less). Crank the engine, and see if the multimeter readout changes. You should get abounce of between -60 and 60 milliVolts. This will confirm you have a good tach signal to the HEI.

2. Confirm you have voltage to the HEI when the switch is in the "run" position, by checking the voltage directly from the positive HEI blade, without unplugging anything, and the ground. This voltage should be identical (+-0.1 volts) to the battery voltage across the battery posts.

3. Check the voltage to the HEI when the engine is cranking, voltage directly from the positive HEI blade, without unplugging anything, and the ground. This should exceed 11 volts, and be identical (+-0.1 volts) to the battery voltage across the battery posts while cranking.

If all 3 of these check out, then we have effectively eliminated the wiring and voltage as problems.

Triple check the wiring polarity from the distributor to the HEI. Even if the wiring is correct, swap the wiring polarity (switch the two wires top to bottom). Try firing it again, just to see.

What is left?
Coil
Module
Coil wire to distributor

 

[magnumdust]

The cap is most likely not the issue. The HEI voltage will jump across it.

Check 3 things and let us know:

1. Unplug the wire from the distributor to the HEI module, and connect your multi-meter to the two wire, in DC millivolt mode (200 mV or less). Crank the engine, and see if the multimeter readout changes. You should get abounce of between -60 and 60 milliVolts. This will confirm you have a good tach signal to the HEI.

2. Confirm you have voltage to the HEI when the switch is in the "run" position, by checking the voltage directly from the HEI blades, without unplugging anything. This voltage should be identical (+-0.1 volts) to the battery voltage across the battery posts.

3. Check the voltage to the HEI when the engine is cranking, voltage directly from the HEI blades, without unplugging anything. This should exceed 11 volts, and be identical (+-0.1 volts) to the battery voltage across the battery posts while cranking.

If all 3 of these check out, then we have effectively eliminated the wiring and voltage as problems.

Triple check the wiring polarity from the distributor to the HEI. Even if the wiring is correct, swap the wiring polarity (switch the two wires top to bottom). Try firing it again, just to see.

What is left?
Coil
Module
Coil wire to distributor

1. i unplugged the dist. plug and connected two prongs to the plug that goes to the distributor, set the meter to 200mv as shown in your picture(luckily, we have the same cheap meter) and turned over the engine. It didnt go over 0.xx(less than .2-3ish). Sorry no pics of it, working alone with some dead time before my first call.

2. With the ignition in the run position put a prong on the "B" blade(red power wire going to my relay) and the other prong on the C blade(black wire goes to neg. on coil). Set to DCV-20. It gave me 0.34v. However, putting one prong to a ground and measuring the C & B blades individually i got readings that were within .1 of the battery measurement.

3. A little hard due to #2 and a low battery(i guess i'll be seeing the parts store for charge number 5. In run battery shows 9.12v, cranking it dips to 8.9 or so. Individual blade measurement(like described in #2) shows 8.7x at each blade when cranking.

Everything connected in the tests minus the dist. plug for #1


PS: i have that plastic shielding, I bought 7ft of it to get rid of the annoying harness tape. I just havent put it on the firewall until i get the ignition finished.(which should hopefully explain why my firewall looks like a mess of wires)

 

[jimmyray]

1. i unplugged the dist. plug and connected two prongs to the plug that goes to the distributor, set the meter to 200mv as shown in your picture(luckily, we have the same cheap meter) and turned over the engine. It didnt go over 0.xx(less than .2-3ish). Sorry no pics of it, working alone with some dead time before my first call.

2. With the ignition in the run position put a prong on the "B" blade(red power wire going to my relay) and the other prong on the C blade(black wire goes to neg. on coil). Set to DCV-20. It gave me 0.34v. However, putting one prong to a ground and measuring the C & B blades individually i got readings that were within .1 of the battery measurement.

3. A little hard due to #2 and a low battery(i guess i'll be seeing the parts store for charge number 5. In run battery shows 9.12v, cranking it dips to 8.9 or so. Individual blade measurement(like described in #2) shows 8.7x at each blade when cranking.

Everything connected in the tests minus the dist. plug for #1


PS: i have that plastic shielding, I bought 7ft of it to get rid of the annoying harness tape. I just havent put it on the firewall until i get the ignition finished.(which should hopefully explain why my firewall looks like a mess of wires)

After all of my careful writing, I still wrote it wrong. Meant to say measure voltage on HEI Positive and the ground.

Sound like your voltage is low. I am also concerned about the signal from your distributor. I would hope you would be getting at least a signal above the 20.0 or so. Are you sure the gap is ok on the reluctor to magnetic pickup? It is supposed to be 0.008". Be sure to check it woth a brass feeler gage!

 

[magnumdust]

After all of my careful writing, I still wrote it wrong. Meant to say measure voltage on HEI Positive and the ground.

Sound like your voltage is low. I am also concerned about the signal from your distributor. I would hope you would be getting at least a signal above the 20.0 or so. Are you sure the gap is ok on the reluctor to magnetic pickup? It is supposed to be 0.008". Be sure to check it woth a brass feeler gage!

It may have been the pickup gap. I checked the gap after reading this and it had a gap that was easily 5x 0.008, if not more. I adjusted it, but then had to take off for work. So tonight at 11:30ish i put it all together and it fired up to my surprise. Shut the engine off and flicked the key again and it fired right up yet again.

I wanted to do some more testing, but i don't like pissing off my neighbors and side pipes are loud. However this seems promising.

 

[jimmyray]

Yes!!!

Did it fire up with the battery in a state of low voltage, or did you recharge it?

 

[magnumdust]

Yes!!!

Did it fire up with the battery in a state of low voltage, or did you recharge it?

It started with the low voltage and again started up quickly this morning 4 times in a row. So that looks like it was the main issue. Now i just need to button up the wiring.

 

[BillGrissom]

Great, glad it sparks now, though your metric of "crank car, does it fire?" is not a conclusive spark test.

Read slower in the future. I told you way back to check for the spark at the coil output wire. That is before the distributor cap, so would have taken the rotor and cap totally out of the equation. Most people have to learn how to read technical info. They first try to skim it like a novel, which doesn't work at all. In Physics and Math classes, you cover maybe 10 pages per week, spending maybe 1 hour per page.

Ideally, you should use a brass feeler gage to set the pickup gap. I don't since I don't have brass feelers. You want the gap as small as possible without crashing into the teeth, including when the vacuum advance moves the plate. If you inspect the Chinese "ready-to-run" distributor, you will see a much smarter design where the gap doesn't need adjusting.

 

[jimmyray]

Any updates?

 

[magnumdust]

Any updates?

So i got everything cleaned up and as far as i can tell its working great(been too busy to get any sort of a road test on it)

Did run into one issue that's stumped me. My vac. advance causes the idle to go nuts when its hooked up. Looked online and it say the airgap was set wrong, which doesnt make sense given that i've set it myself. Its not a huge issue since the vac. advance will be unneccary anyways once i get the spark control setup on my efi kit(next step)

Pics of the mostly finished setup, little odds/ends need to be finished like my tach. wire and cleanly route the plug wires.

 

[jimmyray]

So i got everything cleaned up and as far as i can tell its working great(been too busy to get any sort of a road test on it)

Did run into one issue that's stumped me. My vac. advance causes the idle to go nuts when its hooked up. Looked online and it say the airgap was set wrong, which doesnt make sense given that i've set it myself. Its not a huge issue since the vac. advance will be unneccary anyways once i get the spark control setup on my efi kit(next step)

Pics of the mostly finished setup, little odds/ends need to be finished like my tach. wire and cleanly route the plug wires.

Remove the cap from the distributor. Rotate the engine so that the rotor is just before the pickup metal extension that is incased in plastic. Remove the vacuum advance hose from the carb. Either create the vacuum with your mouth, or use a vacuum tool.

I'll bet the vacuum advance, when it rotates, is moving the pickup coil assembly closer to the rotor. This seems to be common on rebuilt or even new distributors, and is a notorious week link in the Mopar distributor.

The upper plate that the vacuum rod attaches to rotates in response to the vacuum signal. It is also what the pickup coil assembly is mounted to. Either the pivot point hole in the plate is not drilled correct or is too big, or the bend in the plate that supports the pickup is not a 90 degree bend, or both.