HEI distributor swap
#1
HEI distributor swap
Hello, I'm looking to put a HEI performance distributor on my 1991 Dodge Dakota 5.2L LE. I have looked at the wiring diagram and there are three wires. I have found the tachometer wire. But as far as the other two I cannot find which is the power wire to the distributor. And when one of the wires is grounded, it allows the fuel injectors to spray once and some relays to click on and off. Even when jumping the distributor power wire directly to battery, there is still no spark. If anyone has any help or has previous experience any information would be greatly appreciated
#2
It would help to know exactly how much you are modifying the motor.
Do you have the factory service manual for the original wiring?
BTW - There's no "tach" wire off the distributor; tach signal is 2x revolution off the CPU.
And I'm confused.
The factory distributor fires the ECU, which then fires the coil.
And hence might be part of your problem; no signal from the pickup in the distributor, no ASD relay, no coil or injector.
RwP
Do you have the factory service manual for the original wiring?
BTW - There's no "tach" wire off the distributor; tach signal is 2x revolution off the CPU.
And I'm confused.
The factory distributor fires the ECU, which then fires the coil.
And hence might be part of your problem; no signal from the pickup in the distributor, no ASD relay, no coil or injector.
RwP
#3
I purchased a high-performance distributor thinking I could bypass the computer for the spark. It seems this is not the case and will not work. I am now returning the performance distributor and would like to fix it back to stock. My coil keeps burning up. Every time I replace it with a new one it burns up by the end of the day. Could the ASD be bad and burning up my coils?
#4
What coils are you using?
Current is limited by the ECU; the ASD only supplies the 12V feed.
But.
Most "after market" "High Performance" coils are crap, TBH.
And how do you know it's a burned up coil? That is, how are you testing them to verify?
But back to ... you can, if you bypass the computer 100%, and carb or use a stand alone fuel injector controller.
I suggest grabbing the factory service manual (BIG hint: Our trucks don't say "Haynes" or "Chilton" on them!) and studying up how the ignition works on these trucks.
RwP
Current is limited by the ECU; the ASD only supplies the 12V feed.
But.
Most "after market" "High Performance" coils are crap, TBH.
And how do you know it's a burned up coil? That is, how are you testing them to verify?
But back to ... you can, if you bypass the computer 100%, and carb or use a stand alone fuel injector controller.
I suggest grabbing the factory service manual (BIG hint: Our trucks don't say "Haynes" or "Chilton" on them!) and studying up how the ignition works on these trucks.
RwP
#5
When using stock parts from AutoZone or O'Reilly's the stock coil burns up within a day. I check spark directly from the coil when I replace the coil and I have a good spark. Then once the coil burns up I do not have a spark from the coil to the distributor. Because a new coil repeatedly gets burned out, my guess is the ASD is bad or shorting out?.
#6
ASD would have NOTHING to do with that.
ALL it does is supply 12V to injectors, coil, and fuel pump.
"Shorting out" would leave all on all the time; open would leave all OFF all the time.
Have you checked the resistance of the coil? It could be as simple as the CONNECTOR is bad, and quits; but works after you remove/install the coil.
I've included the wiring diagram for a 1996 for the ignition coil; your truck should be very, VERY similar. But might not be; again, before you fight it too much and spend too much money, I'd a) buy or download a copy of the Bishko-sourced Factory Service Manual; b) check the resistance of the primary of a new coil and of a failed coil; c) try a Genuine Mopar coil instead of the DuraSpark or whatever brand you've been using, and d) verify there's no other problem.
RwP
ALL it does is supply 12V to injectors, coil, and fuel pump.
"Shorting out" would leave all on all the time; open would leave all OFF all the time.
Have you checked the resistance of the coil? It could be as simple as the CONNECTOR is bad, and quits; but works after you remove/install the coil.
I've included the wiring diagram for a 1996 for the ignition coil; your truck should be very, VERY similar. But might not be; again, before you fight it too much and spend too much money, I'd a) buy or download a copy of the Bishko-sourced Factory Service Manual; b) check the resistance of the primary of a new coil and of a failed coil; c) try a Genuine Mopar coil instead of the DuraSpark or whatever brand you've been using, and d) verify there's no other problem.
RwP
#7
One more thing that I didn't think about - you DO have 12V to the coil when it's not sparking, right?
If not, then you also have no injector and no fuel pump; time to check the ASD.
But yes, locate a copy of the factory service manual (printed by Bishko; used copies can be found on Ebay) for your 1994 and work from there.
Or just keep flailing at it, tossing money at it without actually trouble shooting it, your choice.
RwP
If not, then you also have no injector and no fuel pump; time to check the ASD.
But yes, locate a copy of the factory service manual (printed by Bishko; used copies can be found on Ebay) for your 1994 and work from there.
Or just keep flailing at it, tossing money at it without actually trouble shooting it, your choice.
RwP
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#8
I've tested the 12 volts to the coil, and I am not getting any power. That is what led me to believe that the ASD might be bad. But my fuel pump and injectors still spray on accessory once for startup and the fuel pump continues to run. At this point I need to find a pigtail for the distributor plug on the engine harness and buy a good mopar coil and get it all back to stock.
It runs when it wants to. It died when I was out and about and we tried to start it for 30 minutes and it did not start. Once we got it home a few days later I was moving it into the shop and I decided to try and start it, it fired right up. This is all with a stock replacement coil from AutoZone .
It runs when it wants to. It died when I was out and about and we tried to start it for 30 minutes and it did not start. Once we got it home a few days later I was moving it into the shop and I decided to try and start it, it fired right up. This is all with a stock replacement coil from AutoZone .
#9
Again, you really need to check the wiring for a 1991.
As I type this, they start at about $22 delivered on Ebay for paper.
Bishko was the original publisher; they show it for $37 for the disk version http://www.autobooksbishko.com/searc...k&category=All .
(Alas, RockAuto no longer lists them; they were $23 there.)
RwP
As I type this, they start at about $22 delivered on Ebay for paper.
Bishko was the original publisher; they show it for $37 for the disk version http://www.autobooksbishko.com/searc...k&category=All .
(Alas, RockAuto no longer lists them; they were $23 there.)
RwP
#10