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Loose wire near exhaust manifold

Posted: Tue May 28, 2013 8:44 am
by rjkoop
After I removed the heat shield I noticed this wire wasn't connected anywhere.

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Any idea what it's for? Looks like a ground and there is even a hole on the frame where it may have once attached to (in picture). It comes out of the same area as the O2/lamdba sensor wire.

Re: Loose wire near exhaust manifold

Posted: Tue May 28, 2013 11:55 am
by BEEK
been a while but as i remember there is a "extra wire in the efi harness that does not connect to anything,

Re: Loose wire near exhaust manifold

Posted: Tue May 28, 2013 12:21 pm
by 81SPIDERMATT
i have 2 black wires in that area ... one goes to o2 sensor (at least i think it is the o2 sensor) same as in your pick.... the other appears to be a ground wire that goes from plug wire holder on top of engine to a bolt on engine bay that holds the coil housing...

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dont have one that disappears into the wire loom

Re: Loose wire near exhaust manifold

Posted: Tue May 28, 2013 3:08 pm
by rjkoop
I think the wire broke for the PO and he just cut it shorter, drilled a small hole in the frame and called it done. Any reason why a ground would have to go directly to the engine? Isn't the engine on rubber mounts so it needs to have a ground attaching to the frame somewhere, no?

Also for the exhaust manifold leak once I took off the heat shield I noticed that one of the exhaust manifold bolts was missing around the area where the leak was. I'm hoping this is causing the leak. I'll try putting a bolt on and torquing correctly. That being said I'd really like to resurface the exhaust manifold but wasn't looking forward to taking it off. Gut feel is try the bolt thing first and hope it's fixed. Maybe next year resurface exhaust manifold.

Re: Loose wire near exhaust manifold

Posted: Tue May 28, 2013 9:35 pm
by rjkoop
I traced the wire and found the other end attached to the cam cover.

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So anyone know what issues this could cause if the engine ground wasn't connected at the other end to the frame? Seems to run fine though.

Re: Loose wire near exhaust manifold

Posted: Tue May 28, 2013 11:22 pm
by blakef
I have a random wire doing nothing in a similar area and was wondering about it as well... I'll try to remember to take a picture tonight when I get home... It is not the engine ground shown above I recently cleaned my grounds so I know they are connected properly. It also isn't the O2 sensor as that is connected already to a different wire. Mine appears to have a black connector on it and hangs down right below the ignition coil, it's pretty grimmed up and doesn't appear to have been plugged into anything in recent history. I also noticed two connectors on the FI harness right by the ECU connector that aren't attached to anything?? Anyways I'll try and take a pic of the engine bay one tonight, maybe it's the same one?

Re: Loose wire near exhaust manifold

Posted: Wed May 29, 2013 6:27 pm
by 81SPIDERMATT
ok i am curious.... found and engine ground ... also found what looks like 2 ground wires on the plenum ... and that ground wire in my picture.... looking for an answer as to why they are there and why it does not seem to matter that koop's wire is not attached? .... my guess would be that he also has an engine ground that works for the whole engine and these are extras just in case??? or resistance to engine ground was too high and they are needed for electronics close to where they are located.... just curious????

Re: Loose wire near exhaust manifold

Posted: Thu May 30, 2013 7:08 am
by rjkoop
81SPIDERMATT wrote:ok i am curious.... found and engine ground ... also found what looks like 2 ground wires on the plenum ... and that ground wire in my picture.... looking for an answer as to why they are there and why it does not seem to matter that koop's wire is not attached? .... my guess would be that he also has an engine ground that works for the whole engine and these are extras just in case??? or resistance to engine ground was too high and they are needed for electronics close to where they are located.... just curious????
Yep. I had a similar extra ground at the fuel pump that I removed and everything is still working fine there. I think I'll reattach this one to the point on the frame where I see a hole was drilled. Maybe there was some issue that the engine was ground but the top of the engine needed an extra ground. Doesn't sure I guess.