97 Ram 2500 No start after rebuild - no power to coil

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Lethalweapon100

Senior Member
Joined
Oct 27, 2014
Posts
363
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Location
NY
Ram Year
1997
Engine
V8 5.9 Magnum
Hi all.

My 228K Mile Ram 2500's 5.9 V8 was getting old and tired, and i dont have time or money to pick up something newer, so I bought a cheap and lower milage 5.9 V8 out of a 95 and went through it with all new gaskets/seals/etc and verified that it was healthier than the old engine. It finally found its way into the truck, only to have it not start after about 20 hours of work.

I immediately narrowed it down:

No power was leaving the coil to go to the distributor.

No power was going to any plug wires.

I unplugged the coil and hooked my multimeter up to it (don't have a test light) and had my helper crank it over. I figured the voltage would at least jump on the screen, which it did not. So it would appear that no power is coming to the coil.

The PCM/harness/everything else is original to the truck. The only thing replaced was hard engine parts and the block.

The truck did run before the swap, just burned 3 qts / week (after plenum fix) and I found a few good chunks in the pan when i pulled it down to put it on the new engine.

I am also confident that i reconnected every wire and ground.

I began to open up the engine harness in order to check for continuity in case maybe i broke a wire by moving it like i did. The coil connector has 2 wires: black w grey tracer and green w orange tracer.

Black w grey goes to pin 5 on the black PCM connector, a quick google tells me its the coil driver.

The green w orange, however, goes up into the engine harness, and then meets 3 other green w orange wires in a piece of shrink tube. One of those 3 comes from pin 12 on the grey connector in the PCM, which is "auto shutdown relay output". One of those wires goes down into the drivers side of the engine harness. The 3rd wire goes over into the bottom of the fuse box. The 4th, obviously, comes from my coil connector.

I also noticed that a green wire w orange tracer comes out of all 8 injector connectors. WTF is all this crap? How am I supposed to test continuity if this "one" wire runs to 800 different places?

Suggestions? Thoughts? Prayers? Any ideas would be highly appreciated.

QUICK EDIT: After some research into how the ASD Relay functions, it makes sense that the green wires are like that. I think ill swap the relay out tomorrow and see if that changes anything.

EDIT #2: I'm getting no power out of my PCM anywhere. No power from the coil driver, no power to any injectors, i even probed a random 5V supply wire and didnt get sh*t from that either. Is my PCM facked or is there some sort of fuse that I might've blown?

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Last edited:

relrobber

Junior Member
Joined
Dec 13, 2014
Posts
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Location
Kensett, AR
Ram Year
2011
Engine
CTD 6.7
Green with orange is a common color code for ground wires. That is why it appears to go everywhere. I know the harness connector changed in '96. Maybe the pinouts don't match on your pcm connector.

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Lethalweapon100

Senior Member
Joined
Oct 27, 2014
Posts
363
Reaction score
35
Location
NY
Ram Year
1997
Engine
V8 5.9 Magnum
Green with orange is a common color code for ground wires. That is why it appears to go everywhere. I know the harness connector changed in '96. Maybe the pinouts don't match on your pcm connector.

Sent from my Nexus 7 using Tapatalk
They do. Because every one ive traced so far has led to the place it says it does. As stated above, green w orange tracer is ASD relay

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