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Discussion Starter · #1 ·
I have an 86 SC that's not running. It cranks but won't turn over. With the ignition in the on position the fuel pump won't make any noise neither will any relays or solenoids make any noise. However jumping the db/yl pin on the service connector starts the pump but I must not be getting spark since it's still not starting.
The car won't give me any codes either, not even 55 which is supposed to appear no matter what, making me think it was a problem with the ecu (which is a Mopar stage 2). I tried replacing the ecu with a stock one, as well as changing out the power module to no effect.
I've consulted the electrical part of MiniMopar and have tested everything it states and basically he's saying it's the Ignition Reference Sensor (aka HEP right?). But the thing is if that's the case would I still not be able to get codes at all? Where is the HEP even located?

Could this be just one loose/broken wire that needs to be replaced?


tl;dr: No spark, fuel (pump does work), or codes (not even 55)
 

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When you first turn the key on the ASD relay is actuated for 1 second to pressurize the fuel rail. The ASD will not be actuated again until the controller sees a crank signal from the HEP.
When you ground the DB/YL wire you are actuating the ASD so the pump should run, there should be power at the + coil and at the DG/BK wire at the injector harness.If all of this is present the ASD is working fine.
If ok crank the engine and while cranking check for power at the + coil, if it is not present the HEP is most likely at fault, they are a common, high failure item.
The HEP is located beneath the dist cap, spend the extra money and replace with a Mopar, aftermarket HEPS seem to fail quickly.
When installing Do Not bend the wires down the side of the distributor as the factory had them or you will damage the wiring. Loop the wiring around to the connectors and secure to the engine harness with wire ties to prevent rubbing and chafing, try to avoid any sharp bends in the wiring.
 

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Discussion Starter · #3 ·
OK, I've replaced the HEP to no effect. I still can't get the ecm to give me anything, and the fuel pump still won't prime with the key in the ignition. What do I look at next?
 

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Lets start from the beginning,we are not going to throw parts at the problem. You say you cannot retrive any fault codes, is the power loss lamp lit and won't flash or is it not lit at all?
 

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Discussion Starter · #5 ·
It no longer lights up. The odd thing is when the car very first stopped running the light WOULD light up, but the engine wouldn't crank. I checked for codes and got nothing but 55. I tried starting it half a dozen times to no avail. Then the fuel pump stopped priming and no power loss light. I then disconnected the - battery terminal, reconnected it and the car would crank but not start. Is there something that would break from trying to start it over and over even though there was no cranking?
 

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Since the power loss lamp no longer lights you will have to start by checking the power feeds and grounds at the controllers.







 

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make sure you give a light tug on each link. thats how i found mine. they looked solid but the one white wire going to the asd relay is what was broke.
 

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Discussion Starter · #10 ·
make sure you give a light tug on each link. thats how i found mine. they looked solid but the one white wire going to the asd relay is what was broke.

I did just that! I'm pretty sure they're good but is there an easy way to check the resistance?
 
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