We're going to have to repair/replace the fuel rail wiring harness because it's damaged like other ppl have posted about. (details below) Is this the same harness that part of it runs under the transmission by any chance? The fuel rail harness sorta runs from the CAP at the top of the engine, over toward the master cylinder, then down and around the exhaust manifold, and from there it's hard to follow. There's a portion of this or some other wiring that runs under the transmission where it's completely soaked from an old leak.

Basically wanting to know where the fuel rail harness runs, so I know if we're dealing with one part to buy or two.

Details:

2003 Caravan 3.3L V6, 179k miles. Runs rough and burns gas. The portion of the fuel rail harness by the exhaust is crunchy like it has been barbecued. There's a P0108 code - bad voltage at the map sensor. New sensor installed (easy and cheap fix), no help. Voltage at sensor is correct, 5.0. Cleared the code, came right back. I don't see how the engine has any idea what it's doing with the wiring so messy, and would bet the P0108 is a false read. The harness I refer to is like APDTY part 022190, or similar.

 

The fuel rail harness is quite short, it only runs from the injectors (under the upper intake manifold) to a plug right behind the coil pack. The other harness you mention is an entirely different part.

The injector harness also contains the wires to the MAP sensor, a short in one of those wires could result in the P0108 code that you are getting.

There have also been many cases where the bad harness causes damage to the PCM, so replacing the harness may not solve your issue.

 

georgef - Thank you, that makes sense.