Dead PCM?
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Joined: Jun 2020
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From: Michigan
Yeah sorry, I thought it was a 2000 MY not a 96. In 96 it's indeed fuse 4.
In any case I'm worried that replacing the PCM either doesn't fix it or it gets fried again as we still don't know what really happened. I'm a little wary of the aftermarket coil. If the high voltage side for some reason arcs over to the control side I can see the PCM getting damaged. There isn't any benefit to running the MSD coil as the truck does not have a high performance/high compression engine.
One idea I had was to remove the 30A fuse and the fuel pump and ASD relays. Make sure the ground at the front of the engine is good. Connect battery, turn on ignition and see if the OBD2 scanner can talk to the PCM again.
In any case I'm worried that replacing the PCM either doesn't fix it or it gets fried again as we still don't know what really happened. I'm a little wary of the aftermarket coil. If the high voltage side for some reason arcs over to the control side I can see the PCM getting damaged. There isn't any benefit to running the MSD coil as the truck does not have a high performance/high compression engine.
One idea I had was to remove the 30A fuse and the fuel pump and ASD relays. Make sure the ground at the front of the engine is good. Connect battery, turn on ignition and see if the OBD2 scanner can talk to the PCM again.
I’m going to the salvage yard tomorrow if I find a stock coil can I just swap it out with my MSD without any other modifications?
im happy to try that which ground on the front of the engine should I check? Like where on the engine is it located?
Last edited by Packwood Digital; Aug 24, 2020 at 05:24 PM.
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I agree about the pcm and MSD.
I’m going to the salvage yard tomorrow if I find a stock coil can I just swap it out with my MSD without any other modifications?
im happy to try that which ground on the front of the engine should I check? Like where on the engine is it located?
I’m going to the salvage yard tomorrow if I find a stock coil can I just swap it out with my MSD without any other modifications?
im happy to try that which ground on the front of the engine should I check? Like where on the engine is it located?
Get the mounting bracket and the connector pigtail with the coil. The ground is between the A/C compressor and the power steering reservoir.
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Professional
Joined: Jun 2020
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From: Michigan
pcm is not plugged in and the negative cable is not on the battery fwiw
i tried two different style testers
the one on the left required a connection to both ground and positive and is “automotive safe” it gives the light at the connector
rhe one on the right is the traditional test light that requires only ground and does NOT give any light.
Last edited by Packwood Digital; Aug 24, 2020 at 09:18 PM.
Thread Starter
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Professional
Joined: Jun 2020
Posts: 245
Likes: 2
From: Michigan
Yeah sorry, I thought it was a 2000 MY not a 96. In 96 it's indeed fuse 4.
In any case I'm worried that replacing the PCM either doesn't fix it or it gets fried again as we still don't know what really happened. I'm a little wary of the aftermarket coil. If the high voltage side for some reason arcs over to the control side I can see the PCM getting damaged. There isn't any benefit to running the MSD coil as the truck does not have a high performance/high compression engine.
One idea I had was to remove the 30A fuse and the fuel pump and ASD relays. Make sure the ground at the front of the engine is good. Connect battery, turn on ignition and see if the OBD2 scanner can talk to the PCM again.
In any case I'm worried that replacing the PCM either doesn't fix it or it gets fried again as we still don't know what really happened. I'm a little wary of the aftermarket coil. If the high voltage side for some reason arcs over to the control side I can see the PCM getting damaged. There isn't any benefit to running the MSD coil as the truck does not have a high performance/high compression engine.
One idea I had was to remove the 30A fuse and the fuel pump and ASD relays. Make sure the ground at the front of the engine is good. Connect battery, turn on ignition and see if the OBD2 scanner can talk to the PCM again.
removed asd, fuel pump relay and 30a fuse. Obd still fails
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Joined: Apr 2010
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From: Clayton MI
The tester on the left is a 'logic' tester. It's reasonably smart, but, you need to be able to interpret what it's telling you. Usually, there are two, or even three lights in there, green means you have power at your test point, red (or yellow) means the circuit goes to ground. The three color fellers will also turn on a (white?) light if it is neither.
I think the PCM is well and truly fried.....
I think the PCM is well and truly fried.....
Thread Starter
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Professional
Joined: Jun 2020
Posts: 245
Likes: 2
From: Michigan
The tester on the left is a 'logic' tester. It's reasonably smart, but, you need to be able to interpret what it's telling you. Usually, there are two, or even three lights in there, green means you have power at your test point, red (or yellow) means the circuit goes to ground. The three color fellers will also turn on a (white?) light if it is neither.
I think the PCM is well and truly fried.....
I think the PCM is well and truly fried.....
lol I went to harbor freight and literally bought every single electrical testing device they have.
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Professional
Joined: Jun 2020
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From: Michigan
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Joined: Apr 2010
Posts: 87,453
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From: Clayton MI
How can there be power on a wire that isn't hooked to anything? That's REALLY weird.