HEI conversion problem: no spark while cranking

-
I

iScamp

Well-Known Member
Joined
Nov 1, 2012
Messages
376
Reaction score
415
Location
North Carolina
Hi FABO Mopar Gurus,
I did a forum search and found some interesting bits but, not my specific problem. Such as Smokinnjokin's thread. So here's the setup:

340 with OEM distrbutor.
New pickup coil (280 ohms according to my meter)
New HEI module (activated by a relay)
Blaster 2 coil. (.7 ohms primary, 12K ohms secondary)
New Accel cap
New Accel rotor
New 8.2mm Taylor spark plug wires

Immediately after installing the listed parts, went for a drive.
When the car is running 70 mph, idle, cruising or hard acceleration: it runs great.
Cold start was o.k.
Hot start o.k.

Get in the car, yesterday (second trip after installing the parts), cranks and runs, no problem.

Hot start: won't run. No spark at coil wire. (replaced the HEI module with a new spare. Still no spark.)

After checking for power,grounds, Ohms, did not find a problem.
Removed the distributor and spun by hand (pickup connected, ignition "on", etc). Lots of hot spark coming from the coil wire.
Reinstalled the distributor. Cranked the engine and as it is cranking; there is one, lone spark from the coil wire. Nothing else.
Reconnected the coil wire to cap. Cranked and cranked, finally it 'caught' and ran. And ran great all the way home.

Why the "no spark" during cranking? (or just a single spark in one instance).

Pickup gap is .016", no advance. It's .008" at full advance.
Module has a decent ground and has the heat sink compound.
 
Are you running thru ballist resistor?
What GM HEI module (not brand) are you running 4 pin or 7 pin.
I run a 4 pin with no resistor. works great and best crank start I've ever seen from a MoPar.
 
wiring-diagram.jpg
 
Clip a meter to coil + When cranking, you should see "same as battery" If the battery drops to say, 11.5 on the starter, then the coil+ should be 11.5. In no case should it be below 10 or 10.5

When running, coil+ should ALSO be "same as battery" with the ballast resistor bypassed.

Did you mount the module to a flat piece for heat sink? You must cut the "tit" off the module on the bottom for it to sit down flat. And it MUST be grounded through the mounting screws.

If you are still using the 2 pin dist. connector, "work" it in/ out several times to scrub the terminals, and inspect it for corrosion. There is nothing but a tiny bit of current going through that connector, that is the AC trigger signals generated by the dist. That connector can be trouble.
 
HEI=PROBLEMS If its in your chevy,ford or mopar. Chinese mopar Ecu units last longer from my experiences.
 
Slantsix64 said:
HEI=PROBLEMS If its in your chevy,ford or mopar. Chinese mopar Ecu units last longer from my experiences.
Click to expand...

Do you actually know what you are talking about or are you just spouting bullshit? There are a few of us on here would say the OPPOSITE. I've run GM HEI modules on several projects, including the now gone Toyota 4 whanger in a Cletrac crawler

_mg_6370cs-jpg.jpg
 
iScamp said:
Hi FABO Mopar Gurus,
I did a forum search and found some interesting bits but, not my specific problem. Such as Smokinnjokin's thread. So here's the setup:

340 with OEM distrbutor.
New pickup coil (280 ohms according to my meter)
New HEI module (activated by a relay)
Blaster 2 coil. (.7 ohms primary, 12K ohms secondary)
New Accel cap
New Accel rotor
New 8.2mm Taylor spark plug wires

Immediately after installing the listed parts, went for a drive.
When the car is running 70 mph, idle, cruising or hard acceleration: it runs great.
Cold start was o.k.
Hot start o.k.

Get in the car, yesterday (second trip after installing the parts), cranks and runs, no problem.

Hot start: won't run. No spark at coil wire. (replaced the HEI module with a new spare. Still no spark.)

After checking for power,grounds, Ohms, did not find a problem.
Removed the distributor and spun by hand (pickup connected, ignition "on", etc). Lots of hot spark coming from the coil wire.
Reinstalled the distributor. Cranked the engine and as it is cranking; there is one, lone spark from the coil wire. Nothing else.
Reconnected the coil wire to cap. Cranked and cranked, finally it 'caught' and ran. And ran great all the way home.

Why the "no spark" during cranking? (or just a single spark in one instance).

Pickup gap is .016", no advance. It's .008" at full advance.
Module has a decent ground and has the heat sink compound.
Click to expand...
Pickup gap is too wide.
 
iScamp said:
4 pin module. No ballast. Same as the diagram you show, except mine has a relay.
Click to expand...
Why a relay- it’s drawing minimum amounts of amperage. Also does your relay toggle “on” during crank and run key positions?
 
67Dart273 said:
Do you actually know what you are talking about or are you just spouting bullshit? There are a few of us on here would say the OPPOSITE. I've run GM HEI modules on several projects, including the now gone Toyota 4 whanger in a Cletrac crawle

View attachment 1715412081
Click to expand...

that’s cool! I want to see more pictures of that crawler.
 
Syleng1 said:
Why a relay- it’s drawing minimum amounts of amperage. Also does your relay toggle “on” during crank and run key positions?
Click to expand...

I've recommended a relay in the run circuit. The reason is that circuit supplies ANY underhood loads during "run," including the alternator field and VR. Voltage drop in that circuit........which is a common problem.......causes the charging system to run OVER voltage, because the VR power connection is also voltage sense. If it sees low (dropped) voltage "it thinks" the battery is low and ramps up charging voltage. There are two ways to check that. One is key in "run" with engine stopped. Compare voltage at the ballast from the key to battery+. Another is to run the car, battery charged, at high idle. Compare battery charge to the ballast "run" terminal. If the ballast runs at (correct)13.8--13.2, and the battery is higher, then you have a drop problem in that circuit
 
Is it normal for the pickup gap to change with the advance?


UPDATE: Just found this comment on someone's site.
Lean burn engines through 1977 (first generation system) have two pickup air gaps. The gap is .008 in. for start, and .012 in. for run. The second generation system has only one distributor pick-up.

Sounds like your gaps are off and reversed?
 
Last edited:
Slantsix64 said:
HEI=PROBLEMS If its in your chevy,ford or mopar. Chinese mopar Ecu units last longer from my experiences.
Click to expand...

iScamp said:
I always hear the virtues of the HEI , here and on Youtube. But, I"ll go along with your comment.
Click to expand...

Been running HEI for 5 years on a daily driver 70's Mopar without so much as a single glitch or no start.
I also built and sold LOTS of HEI conversion kits here, and any problem that kept the car from running was either an installation error or a problem with the car wiring causing low voltage, or the module wasn't grounded well.
 
The relay was installed previously. This HEI system was on the car when purchased. (it's been a nuisance *iScamp's brother's opinion*).
As for reluctor gap. Because the advance plate pivots around a different point than the center shaft, the gap changes as the plate moves.
 
Cuda416 said:
Is it normal for the pickup gap to change with the advance?


UPDATE: Just found this comment on someone's site.
Lean burn engines through 1977 (first generation system) have two pickup air gaps. The gap is .008 in. for start, and .012 in. for run. The second generation system has only one distributor pick-up.

Sounds like your gaps are off and reversed?
Click to expand...

It's not supposed to be normal, but it happens anyway due to the geometry of the advance plate pivot point.:D
I have seen no way of fixing that within reason.
 
Just to be clear ( and I've used HEI on a Slant 6 and the 66 Barracuda.)

Starting is better, rev is better. Less misfires and better fuel burning.... as long as it is set up correctly.
ALSO THIS IS 40 YEAR OLD TECHNOLOGY. it is not perfect, or will not last forever. I made plenty of repairs to it back in the 80's working for a GM dealership. Modules go south, pick ups were wonky and arcing across terminals of those HEI large caps were notorious on the GM engines. I was a MASTER GM Tech.

All I am saying is this HEI conversion thing is Better than the Chrysler Electronic ignition found in the little box on the fenders. But the Chrysler pick up were better than the factory GM's.
I still run the Factory E.I. on my 72' Demon 340 4 speed car. It works well... until the boxes lets the smoke out and melts the plastic over my inner fender. LOL! or the Ballest pops. With H.E.I., there are issues as well. Over heating, fatigue, vibration, over voltage, hard to hide outside the large distributor. What ever. I am sorry for stealing the post from the original Poster. IScamp- the floor is yours.
 
67Dart273 said:
Do you actually know what you are talking about or are you just spouting bullshit? There are a few of us on here would say the OPPOSITE. I've run GM HEI modules on several projects, including the now gone Toyota 4 whanger in a Cletrac crawler

View attachment 1715412081
Click to expand...
Yup i do, HEI set up on my dart would go out on the freeway on the street tried every brand standard bwd accel only one that lasted the longest DUI, every time i would pull into the 5k would burn out, or just street driving as well you swap you module out for a new china one see how long it lasts. sometimes the module would last 8 months sometimes 2 months sometimes 6 months, my old neighbor also has a chevy with the hei going out every couple months. Went back to mopar ignition solid 2 years no fail . If it worked and was reliable i would keep it cause i could tell a difference in warm up etc. but nope
 
TrailBeast said:
Been running HEI for 5 years on a daily driver 70's Mopar without so much as a single glitch or no start.
I also built and sold LOTS of HEI conversion kits here, and any problem that kept the car from running was either an installation error or a problem with the car wiring causing low voltage, or the module wasn't grounded well.
Click to expand...

Trailbeast,
Tell me about your conversion kits or direct me to a place on the forum/internet that I can learn about it, please. Do you still sell them? Pictures? I'm very interested. The components on my car appear to be a hodgepodge of parts.
 
Slantsix64 said:
Yup i do, HEI set up on my dart would go out on the freeway on the street tried every brand standard bwd accel only one that lasted the longest DUI, every time i would pull into the 5k would burn out, or just street driving as well you swap you module out for a new china one see how long it lasts. sometimes the module would last 8 months sometimes 2 months sometimes 6 months, my old neighbor also has a chevy with the hei going out every couple months. Went back to mopar ignition solid 2 years no fail . If it worked and was reliable i would keep it cause i could tell a difference in warm up etc. but nope
Click to expand...

I would suggest it is something with the installation or possibly even a charging problem. If the folks I knew failed these things at the rate you claim, they would be down there throwing rocks through the parts store windows. Your neighbor replaces an HEI every 2 months? I call bullshit.

I have no dog in the GM fight. I use these because they are easy to get, not very expensive, and they work. Anybody who thinks a modern parts store Chinese Mopar module is good quality is fooling themselves.

And I'm not against Mopar. I converted my 340 swapped 70 RR to Mopar breakerless sometime around 1973. And there was no internet. I once had a 62 Landcruiser with a Mopar smallblock. It used variously Mopar ECU and MSD direct replacement CDI. And I've had others before and since.

If these fail as bad as you say, there would have to be a special line at the parts stores just for guys buying new modules.
 
67Dart273 said:
I would suggest it is something with the installation or possibly even a charging problem. If the folks I knew failed these things at the rate you claim, they would be down there throwing rocks through the parts store windows. Your neighbor replaces an HEI every 2 months? I call bullshit.

I have no dog in the GM fight. I use these because they are easy to get, not very expensive, and they work. Anybody who thinks a modern parts store Chinese Mopar module is good quality is fooling themselves.

And I'm not against Mopar. I converted my 340 swapped 70 RR to Mopar breakerless sometime around 1973. And there was no internet. I once had a 62 Landcruiser with a Mopar smallblock. It used variously Mopar ECU and MSD direct replacement CDI. And I've had others before and since.

If these fail as bad as you say, there would have to be a special line at the parts stores just for guys buying new modules.
Click to expand...
Well thats my experience, 30-40 miles a day daily driving 6 days out of the week. Was not reliable enough for me. You said charging issue? what would the issue be? overcharging ? or corrosion on connectons?
 
iScamp said:
Trailbeast,
Tell me about your conversion kits or direct me to a place on the forum/internet that I can learn about it, please. Do you still sell them? Pictures? I'm very interested. The components on my car appear to be a hodgepodge of parts.
Click to expand...

I don't build them any longer, but I assembled and sold ready to connect kits using the 8 pin modules with the weatherpak connectors.
These had no blade style connections, but all water tight snap together terminals just like the vehicles they ran on.
They also used the OE Mopar electronic distributors which were modified with a performance advance curve using the 925B spring kits and the total timing limit plates from www.4secondsflat.com.
I also assembled and sold those ready to install.
Also did a few HEI module into the OE Mopar ECU for a couple of guys so everything looked and connected like factory.
That one pic of the kit installed in my car is the same kit I installed 5 or so years ago on my daily driver and it still runs perfect.

8 pin wiring.jpg


kit.JPG


installed.jpg


distributor.jpg


4Pinback.JPG


DSCF0010.JPG
 
All aftermarket and wiring changes aside... When you get a single spark as ign' switch returns from start to run, the fault can be the ign' switch. I would disconnect and check it at its harness connector under the dash. If good there, my next stop is bulkhead connector.
What I'm saying is regardless what we do downstream, we're still relying on a lot of the cars OEM wiring and components.
 
RedFish said:
All aftermarket and wiring changes aside... When you get a single spark as ign' switch returns from start to run, the fault can be the ign' switch. I would disconnect and check it at its harness connector under the dash. If good there, my next stop is bulkhead connector.
What I'm saying is regardless what we do downstream, we're still relying on a lot of the cars OEM wiring and components.
Click to expand...


If you are referring to my symptoms listed above, the "lone spark" was during Start, while cranking. The key was being held at Start and the one spark occurred during cranking.
I certainly agree that we are dealing with wiring components that are far older than Chrysler ever considered them to be operating.
Incidentally, when I checked for spark just by cycling the key, Run to Off (engine not running). I did not get any spark.
During the troubleshooting process, I straight wired the relay to the battery, bypassing the ignition switch, harness, etc.
 
You must log in or register to reply here.
-

Back
Top