HEI question

[1986ChrisK10]

Hello guys,
So the other day the truck randomly shut off and I lost spark. To make it a short story, while putting in the new ignition control module. I noticed that the four way plug wasn't plugged in. I left it unplugged and the truck came to life even faster then when I first got it going last week.

*its a new to me truck with a 70's 350 in it*

Come to find out the origanal owner kept the 305 distributor and used it in the 350.

Now, when I shut it off and plugged it in, it ran rough and when I blipped the throttle it sounded like a shot gun going off. I have since left it unplugged and it drives with no issues unplugged.

I barrowed the picture from 72xxxx, sorry forgot his name. *no offense*

So my question is, why is it running better with it unpluggedd. It appears that it only has two wire plugs going into the opposite side of the distributor.



Any input is greatly appreciated.

 

[1986ChrisK10]

Sorry forgot to add, its that plug right by the grommet for the wires going into the cab in the above picture.

 

[bucket]

It's for the electronically controlled spark. A troubled system as far as I'm concerned. Mine acted up on me similar to what you describe, I just put in another dizzy that I had on hand. It's been awhile though, I don't remember if that plug was already undone or not.

 

[1986ChrisK10]

Thanks bucket. I haven't really been able to drive this truck far down the road. Trying to make it more road worthy. It will be getting a LS swap this fall/winter.

 

[Camar068]

Went through the same issue as you recently. Swapped distributor and it fired right up. I was going to rebuild the working unit for about $40, but someone pointed out Skip Whites distributors for $48 shipped. Runs great now.

http://www.skipwhiteperformance.com/listview.aspx?Product=A&Sub=A