Failing Ignition Modules

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59bisquik

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Ok guys, I don't have a A body car but use a 340 distributor setup in my 57 325 Hemi engine. I got a kit a few years ago that was a replacement for the older points distributor. It has the module, ballast resistor etc.
The truck has been sitting for a while and when I went to fire it up, I had no spark. I troubleshot it down to the ECU. I have replaced it once before for the same problem.
I seem to find a pile of discussions talking about how horrible aftermarket ECU's are. Since I have replaced it before and and don't want to keep replacing ignition modules, I decided to replace the ECU with the HEI module. I got the new module in and it fired right up. It ran for about 5 minutes and then quit and now has no spark. Napa was supposed to have a good module and I will try to return it tomorrow. Maybe it was bad off the shelf. However, what am I doing wrong that I keep going through modules?
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How did you mount the module. It MUST have some form of heat sink. There is a "tit" on the bottom of the module, you either must remove it or provide a clearance hole at the mounting. Mounting must be flat, and "really should" have some thermal compound, although I had a couple of set-ups that did not use thermal "grease."

Also could be a bad coil I would think AKA partly shorted drawing way more current that it should.
 
I didn't have it mounted yet, just testing it out before I made a heat sink and mounted it under the dash. However, it was room temperature to the touch during its 5 minutes of run time.
It has an Accel Yellow coil on it. I have not measured the resistance of it yet.
 
I went through these issues before.

What modules and more specifically how are they connected.

I have used MSD, Mallory and really mostly Chrysler boxes. Had issues where good fire when new and then after one high RPM pass they were toast.

After resto and absolute complete full re-wire, I decided on Pertronix III. It is really just a GM HEI with adjustable RPM limit hidden in a factory points type dizzy. I have had no issues at all! Great fire and quick start and no misses now for 6 + years at all RPM's.

All said, I relate it faulty wiring from the get go! Either poor grounding or voltage irregularities due to old wiring.

One must use the correct components, to include coil, ignition wires and more, with the prescribed unit to achieve the best results!
 
59bisquik said:
I didn't have it mounted yet, just testing it out before I made a heat sink and mounted it under the dash. However, it was room temperature to the touch during its 5 minutes of run time.
It has an Accel Yellow coil on it. I have not measured the resistance of it yet.
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?? I've been told that SECONDS will kill a GM module if it is not mounted
 
Put points in it and drive away.
 
If the module is not earthed, there will be no spark; the module is earthed through the two mounting ferrules. I do not believe 5 min of running without a heatsink will damage the module.
If you want to try it temporarily, fit a small screw & nut to each ferrule, & connect together via piece of wire, then earth [ ground ] this wire.
If you decide to keep the module & mount it on a HS, the new silver heat paste has better heat transfer capability than the old white paste.
 
I had a bolt thru the hole and a ground wire running to the frame so it was grounded and hooked up properly. Just not mounted to a heat sink. It has all new wiring that came with the kit. There is no old wiring in the ignition circuit.
I am debating on just upgrading to a Mallory or MSD style unit with a matching coil. I need to get this figured out so I can get her back on the road and then move onto my next project of getting my Hilborn to work on it.
 
Is your accel coil an ecore type? The coil should be matched to the module. HEI requires an ecore coil. Although I’ve heard blaster 2 coils work. I’m using an accel ecore and haven’t had any problems.
 
Actually I used a bone stock Mopar factory coil on my 67. HEI are VERY adaptable to coils it seems. s However, as I mentioned, if you have one that is partly shorted primary, that might be a different matter
 
67Dart273 said:
Actually I used a bone stock Mopar factory coil on my 67. HEI are VERY adaptable to coils it seems. s However, as I mentioned, if you have one that is partly shorted primary, that might be a different matter
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Thanks Del. I quoted what I’ve read and thought I learned from the inter web and such before I converted to HEI.
 
I believe I have a stock coil laying around. I will give it a shot before I get too carried away.
As for the Accel, it is a Super Stock 8140M. I originally had a ballast resistor on it that came with the kit. I was reading that its not needed and removed it when installing the HEI module. It is advertised at 1.4 ohms primary and 9.2k secondary. I read 1.5 primary and 9.9k secondary.
 
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Sounds like your kit consists of the 1970's Mopar electronic design. Many here recommend them as an upgrade from points, but more wiring effort and anything w/ a ballast is old-fashioned electronics (no dwell control). Also, the ECU modules often fail, especially the Chinese knock-offs. A Ningbo "ready-to-run" distributor would have been easier ($40 ebay + $20 e-core coil). Since you already have a Mopar e-distributor, you could use that to trigger a GM 8-pin HEI w/ their coil (1985-95 V-8 pickup). Just a few wires to connect and many posts here. TrailBeast sells a kit.
 
I dug an old coil out of the shed from my 270 poly. Its a 12v and needed a ballast. I hooked it up and she has been running a good portion of the morning. Looks like the Accel coil might be the culprit. Thanks for the help guys.
 
A lot of us old guys still are use to a time when new parts were good, and double or triple faults were rare. Now it is not unusual to get a bad part new, maybe two or three times in a row.

I bought a cheap house brand coil (Masterpro?) at Oreilly awhile back. Lasted about a month. Went back to buy a better one. Took a Standard Ignition one out of the box. It was the same coil. Bought a Chrome Mr Gasket instead. I has been working good for awhile.
 
I’ve done that HEI conversion on a two vehicles. One was successful (79 Cordoba w/ 100 amp alternator) and the other a failure (67 A100 van w/slant and 60 amp alternator) Got the idea off of the Slant 6 forum, SlantSixDan I believe did the good write up on how to do it. Aside from burning out an Autozone module at first, I installed the Echlin module on the Cordoba with excellent results and it lasted for the time we had it. Large gauge wire, good grounds and a thick heat sink using dielectric grease was used. On the van I did the same, but the alternator didn’t put out enough amps, the van has old wiring and with headlights etc running coming to a stop it would conk out. Not enough juice to keep the ignition working. Ditched it for the Chrysler setup and had no issues, but the HEI performed better on both than the Chrysler version especially at startup, idle and with throttle response. Good grounds, heat sink and proper charging at idle are key to module life
 
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