Trouble shoot my HEI conversion?

[Canadian1968]

I did the hide away HEI module conversion on 68 Charger with a mild built 440 . There was nothing wrong with the Mopar orange box / ignition currently , just more or less something for me to play with that is SUPPOSED to offer a strong more consistent spark.

Here is what I did.

Dug out the the inside of an extra orange ecu Box I had. Clipped the ends off the transistor that sits on top. Soldered some new wire wires to the pins of the original orange box harness. I am using an ACDelco HEI 4 prong module. Wired it up correctly, and the fastened it to the orange ECU box by running a bolt threw the HEI module mounting hole and then threw to original mounting hole that holds the transistor on top of the mopar unit ( USING ALL THE THERMAL COMPOUND offered with the module) .

I hollowed out an extra ballast resistor I had , and connected it with 10 awg wire and then filled it back with some putty epoxy.

Coil is a Summit E-coil (850615).

Regular Mopar electronic Distributor

Made my own coil wire with a Taylor Kit for the coil to distributor.

Problem is, car seems to run fine until it warms up. Once warm the car will just die randomly sitting idle . It will die just sitting in park, and doesn't seem to like when I throw it in drive, will bog down , not always die, but it doens't seem to like it.

I just got a new coil from summit , the first one I got had something rattling inside I figured that was my problem. But this brand new one does the same thing, so that can be it.

Thoughts suggestions......

At the end of the day, I will just throw original stuff back on, all plug and play which is why i did it. BUT I like to know what this isn't working...... Thoughts?

 

[RJRENTON]

I did the hide away HEI module conversion on 68 Charger with a mild built 440 . There was nothing wrong with the Mopar orange box / ignition currently , just more or less something for me to play with that is SUPPOSED to offer a strong more consistent spark.

Here is what I did.

Dug out the the inside of an extra orange ecu Box I had. Clipped the ends off the transistor that sits on top. Soldered some new wire wires to the pins of the original orange box harness. I am using an ACDelco HEI 4 prong module. Wired it up correctly, and the fastened it to the orange ECU box by running a bolt threw the HEI module mounting hole and then threw to original mounting hole that holds the transistor on top of the mopar unit ( USING ALL THE THERMAL COMPOUND offered with the module) .

I hollowed out an extra ballast resistor I had , and connected it with 10 awg wire and then filled it back with some putty epoxy.

Coil is a Summit E-coil (850615).

Regular Mopar electronic Distributor

Made my own coil wire with a Taylor Kit for the coil to distributor.

Problem is, car seems to run fine until it warms up. Once warm the car will just die randomly sitting idle . It will die just sitting in park, and doesn't seem to like when I throw it in drive, will bog down , not always die, but it doens't seem to like it.

I just got a new coil from summit , the first one I got had something rattling inside I figured that was my problem. But this brand new one does the same thing, so that can be it.

Thoughts suggestions......

At the end of the day, I will just throw original stuff back on, all plug and play which is why i did it. BUT I like to know what this isn't working...... Thoughts?

Just a little POSSIBLE thoughts to consider....
Is the pickup coil to the GM HEI module connections correct? If the polarity is reversed to the HEI, the pulse will be of opposite polarity, POSSIBLY causing inaccurate triggering. The GM pickup coil's construction is a star tooth magnet and the rotating member, that aligns with each stationary "tooth" for every cylinder firing event. This MAY present a different wave shape pulse (rate of rise and/or amplitude) different from that furnished by the Mopar reluctor/pickup. IF the HEI's internal circuit interprets the pulse incorrectly, because of the pulse's wave shape, it is likely to cause erratic behavior and the symptoms you describe. Its highly UNLIKELY that you have a ground connection problem. Just my opinion of course......
BOB RENTON

 

[Carcinogen]

Check for 12+ volts at coil, I had to use relay as voltage was low even with ballast resistor removed. Low voltage caused by everything being old/corroded.

Problem dying might be loose/corroded connection at firewall connector.

 

[Canadian1968]

I did check power at the coil and getting full system voltage 14+. Bob I did read about what you talking about when I was researching the install. There is a slight chance I have it back wards. It's a simple thing to check.

I don't think it's a heat related problem but i did add a 1/8" piece of aluminum under the module to help even more with heat disapation . I also added a ground wire from one of the mounting holes in the module , to the case which is then grounded directly to the block.

Will have some time later today to play with it. See what u come up with

 

[Canadian1968]

Well had sometime to play around.
I switched the two wires from the Distributor pick up , and the car would barely run. So that was not the problem.
Switched them back , car seemed to be running fine so I decided to take it for a quick wash. Got the the first corner at the end of the street and the car died as I came to a stop. Car fired right back up ( which is weird that it always fires back up with no problem at all ) Back up into side street and the car died again.

Annoyed as hell took it back home and swapped back to all the original mopar ecu and ballast. Fired it up and went to and washed the car, no problems as all , went for a short drive after washing it and ZERO problems. I guess it just goes to show, if its not broken don't fix it hahaha.

I now think it has to be something to do with the module, or IT could be one of my connections made with the new wires inside the box.
I might play around see if I can find a poor connection . But no real rush to try it again, I might try another module down the road. But for now just going to stick with what works !

 

[RemCharger]

Have you thought about trying a Dura-Spark?

 

[RJRENTON]

Have you thought about trying a Dura-Spark?

FoMoCo's Dura-Spark is another alternative but uses a large cap and rotor but can become equally complex to troubleshoot snd expensive to repair......just my opinion of course
BOB RENTON

 

[Gold Rush]

You've touched on the HEI module heat issue a couple times so let's visit that subject again. Remember all the HELL GM owners went thru because that module was inside the distributor COOKING? Here is a link that might interest you. I completed this conversion using the stock electronic distributor on my '74 400 engine. Mounted the Summit Racing E-Core coil on the firewall and plumbed everything to and from it. I went from a pretty weak spark to one that will easily jump a quarter inch gap. Here is the link. http://www.designed2drive.com/

 

[Canadian1968]

You've touched on the HEI module heat issue a couple times so let's visit that subject again. Remember all the HELL GM owners went thru because that module was inside the distributor COOKING? Here is a link that might interest you. I completed this conversion using the stock electronic distributor on my '74 400 engine. Mounted the Summit Racing E-Core coil on the firewall and plumbed everything to and from it. I went from a pretty weak spark to one that will easily jump a quarter inch gap. Here is the link. http://www.designed2drive.com/

I did read multiple times it is important to keep the module cool. But I just don't feel l this is the problem in my case. The Orange ecu box is completely open on the back and with a washer under each mounting screw of the box, this allows for a decent air flow gap from the fire wall. This with piece of aluminum I added and the basic design of the box itself which included a heat sink already, I have hard time thinking heat is my problem, especially that fast ?? I also did do temperature checks a few times during my trouble shooting, and really there was nothing crazy between other objects on the fire wall and the orange box itself.

Also the car ALWAYS fired up right after it stalled, i mean immediately. if the module was over heating i would think it would not start right away? or die almost instantly again???

The two common things that are were always present when it dies is, heat and idle or close to . Never died during cruise or driving. Its annoying lol.

I have lots of time to tinker here in Ontario with us still being under a lot of covid restrictions . So i may fab up another mounting idea and scrap the orange box idea.

 

[Milo]

I know this is a old post but I think the problem is the resistor you put in I did not use a resistor and all is fine

 

[RemCharger]

I hollowed out an extra ballast resistor I had , and connected it with 10 awg wire and then filled it back with some putty epoxy.

I know this is a old post but I think the problem is the resistor you put in I did not use a resistor and all is fine