Big Bird gave me a computer controlled HEI for Christmas. Thanks again Big Bird. Unfortunately, the four pin for the ecu hook up was cut. I bought a four pin weatherpack connector, but I'm not sure what goes to what. You can see the what colors and in what order the wires from my Holley Pro-jection ECU connector are. The black wire from the dizzy is obviously a ground. And the yellow wire from the ecu is for the ecu tachometer. What hooks up to what. Anyone have an 86 or later dizzy picture with the four pin plug. The dizzy has a brown, red, orange, and black wire comming out in that order. The ecu has a black, red, yellow, and blue wire comming out in that order. What hooks up to what?
Bee Jay

 

If someone doesn't answer by the end of the day I'll snap a picture of mine when I get home tonight.

 

Beej, here is how it breaks down.



I have that same distributor in my shed, but with the plug still wired to the distributor. If you have any other questions just let me know.

 

Thanks Durango Kidd. What I need now is a picture of the four pin plug, so that I can see how a,b,c, and d are arranged on the end that plugs into the ecu. I'm pretty sure that the black (d) goes to the black ecu wire.
Bee Jay

 

Thanks Dude. That would be cool.
Bee Jay

 

I actually took a picture of my plug but the wire colors are all hard to make out and you can't read the letters.

However, if you're looking at the plug so you can read the letters, they go from left to right like this. D, C, B, A.

Here's a pic, with color coding that corresponds to your new plug.

 

BJ, I dunno why, but the pix DB has there the colors are different than what I have....so to keep in mind that the wire colors are not all that important, the only one that seems to agree with MY install is the black one, i'ts a computer ref ground to the dist aluminum body, so they absolutely not having any bad ground causing a error in the computer signals....
so that leaves just 3 wires.....now on the chip itself they are stamped B R E from outer edge toward the middle.....

B is your interrupt wire, the Tan Black that you pull to set base timing.....8*

E is the wire for EST, a signal wire to the computer, typically white.....

R is the Reference wire, and is typically purple with a white stripe for my stuff.....


the base timing ref, nothing but a 0-5 pulse after modifying the signal from the magnetic coil on bottom, is what the car will run with, it will act the same as a normal HEI with vacuum advance when the feedback wire is pulled to set timing, ie...NO advance, as it it not told to advance a damn thing by the computer,.....so the dawg just set there....

when you reconnect the tan/blk or Bypass wire, you get a signal from the computer telling the dizzy to advance and by how much.....when you restart the car, it will not do that untill you kill and restart the engine....

hope this helps.....I dunno whay/why DB's pix there is different than mine....

aftermarket wiring??? dunno...

but go by the markings on the large black chip on the dizzy base with heatsink compound....

 

That last picture I posted, with the color code references, I was using BJ's new after market harness colors for easy reference.

My distributor has the same colored wires, but his after market one has odd colors so I just matched them to their corresponding color on his distributor for him.

 

Thanks DB, but that is not the plug, that is just where the wires enter into the disributor. I need a shot of the other end of the wires, the part that plugs into the ecu harness. I don't think they are in the same order on the plug as they are exiting the distibutor.
Bee Jay

 

Oh, never mind. I see what you did now. Thanks.
Bee Jay

 

OK, here is what I did.

You can see the letters on the weatherpack connector. DB says that abcd should hook up to dabc. I think I have it right. Check it out and comment please.
Bee Jay

 

Yep, that looks correct. Good work.

 

Thanks DB. Which one is it that I disconnect to set initial timing again? Next I gotta figure out how to wire in the MSD. I gotta go to Sacramento this weekend, so maybe I'll drop it in and try it next week sometime.
Bee Jay

 

To set the timing, disconnect this wire.

 

Got it.
Thanks
Bee Jay

 

IT RUNS!
OK, the dizzy is in and the car finally started. With no vacuum advance nipple to point at the valve cover bolt, my usual starting point, it took a while to find a good clocking to get the car started. Once running, I set the initial advance at 10 degrees idling at 900 rpm. But when I rohooked the red ECU advance wire, the car started running really bad. The fuel injection graph is set at 8 degrees at 700 rpm, so I assumed that it would be 8 degrees plus the 10 I set initial, or 18 degrees at idle. Just where the car always loved to run. I put the timing light on it and it read 8 degrees. The computer took 2 degrees out to get it to the 8 degrees in the table/graph. So now I have to build an advance table. With my weights and vacuum, I always set it for 38 degrees centrifugal, all in by 2500 rpm. Plus 10 degrees vacuum thrown in at low load, high vacuum situations. So, I'm guessing I build the table with 38 degrees total advance at high throttle openings above 2500 degrees, 48 degrees total advance above 2500 degrees at low throttle openings. I'll go look at Lars papers again, but am I on the right path? Help!!!
Bee Jay