Possible wiring harness issue
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Tuned
Joined: Dec 2020
Posts: 338
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Possible wiring harness issue
My truck ran great Saturday when I started it Sunday running very rough now. Is this maybe a under valve cover wiring harness issue. As best I can I have inspected the harness on top of engine and it looks all good. Unplugged icp sensor no change
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,355
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From: Lake Hartwell, GA
Without a scan tool, you are left to visual and audio inspections. If you feel the problem is near or in the valve covers, take a close look.
Most parts stores don't have the right protocol scan tools.
Most parts stores don't have the right protocol scan tools.
Hotshot
Joined: Mar 2014
Posts: 10,750
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From: Douglassville, PA
I'd start by checking your harness connections first and if that doesn't solve it, look under the valve covers. Check on the driver's side where the harness runs up over the valve cover. Frequently, the wires rub through and short out there. Then go from there.
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Tuned
Joined: Dec 2020
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I have looked at all this and all seems well
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From: Lake Hartwell, GA
Start with the last link, the Q&A.
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FTE Leadership Emeritus
Joined: May 2014
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From: Lake Hartwell, GA
If the UVCH on the driver side under the valve cover has come loose, the EGT would be low because that bank is not firing.
Also, the IDM is capable of shutting down the bank if it sees a problem with at least 1 injector. If you had a scan tool, you could run a buzz test in under 30 seconds and have a good idea of where to look.
Since you don't, you will have to get your tools and start taking parts off.
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Tuned
Joined: Dec 2020
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Do you have an IR temperature gun you can shoot each cylinder at the manifold with?
If the UVCH on the driver side under the valve cover has come loose, the EGT would be low because that bank is not firing.
Also, the IDM is capable of shutting down the bank if it sees a problem with at least 1 injector. If you had a scan tool, you could run a buzz test in under 30 seconds and have a good idea of where to look.
Since you don't, you will have to get your tools and start taking parts off.
If the UVCH on the driver side under the valve cover has come loose, the EGT would be low because that bank is not firing.
Also, the IDM is capable of shutting down the bank if it sees a problem with at least 1 injector. If you had a scan tool, you could run a buzz test in under 30 seconds and have a good idea of where to look.
Since you don't, you will have to get your tools and start taking parts off.
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,355
Likes: 5,951
From: Lake Hartwell, GA
That is a very common failure point and why the posts above requested further examination of the wiring and connections. Look into the 50 cent mod or the 52 cent mod while you are there.
The updated UVCH is not as prone to loosening, but is still possible. I did the 50 cent mod on my new International UVCH's and gaskets several years ago after failing to properly install the clips made to resolve the same potential issue.
The updated UVCH is not as prone to loosening, but is still possible. I did the 50 cent mod on my new International UVCH's and gaskets several years ago after failing to properly install the clips made to resolve the same potential issue.
