When your looking at the UVCH harness clip is any small gap where it plugs in too much. I'am seeing about 1/64". I was out at Lincoln City on the Oregon coast last week finishing the last few days of a 4300 mile trip through the western states and the truck shuts off. Fired right back off and ran fine for awhile then did it repeatedly to the point where I couldn't trust it to get me down the road pulling the 5er. Made it into the RV park and started looking at it. With the truck idling I could shut it off by pushing down on the inboard side of the large square plug main harness above the valve cover. Tried a number of different wire positions and did some test runs. Ended up wire tying the main harness up to the bottom side of the IC tube and made it home 250 miles no problem. I saw no problem at the time with the injector plug at the top of the valve cover. I'am not seeing any chafe issues with UVCH harness either. I suppose the problem could be right in the main harness. Any thoughts. Thanks

Tom
2003 F350 4x4 Lariat CCSB SRW, Autometer Z Series Gauges, 4"Diamond EyeTB,
JWVB, 6.0Trans cooler, 6637, F5 DP Tuner, HPX, IH Bellowed Up-Pipes, Foil Delete, WW, Airlift Rear Bags, Zoodad, Recon LED Cab Lights, GPR-LED, 05 Mirrors, Upper Rad Hose

 

It's not your UVCH. It's the 42 pin connector (the square box over the driver side valve cover with the bolt in the middle of it). That is the connection point between the IDM and the UVCH, along with some other stuff.

It's actually a common chaff point. Either the wires below that box are chaffed and are shorting out against the valve cover, or the wires behind that box are chaffed and shorting against the bracket that holds the box. Either location can cause the wires to short to ground, which resets the PCM. It can cause a stall, no start, sputter, or all sorts of issues.

Use a 10mm socket and unscrew the bolt. Unplug the connector and inspect the wiring below the box. Tape up any damaged wires and push on the top of the bracket so it bends those wires away from the valve cover. Press the clip on top and the back half of the box will slide off the bracket so you can inspect the wiring out the back of the box.

 

Thanks Chris. I did in fact find four seperate wires that had chafed through the wire insulation on the bottom side of the 42 pin plug. However I did a butt connection repair to all of them, put things back together and still was able to shut it down at idle be pushing down on the harness. Maybe the problem lies further into the harness itself or perhaps in the plug.

Tom
2003 F350 4x4 Lariat CCSB SRW, Autometer Z Series Gauges, 4"Diamond EyeTB,
JWVB, 6.0Trans cooler, 6637, F5 DP Tuner, HPX, IH Bellowed Up-Pipes, Foil Delete, WW, Airlift Rear Bags, Zoodad, Recon LED Cab Lights, GPR-LED, 05 Mirrors, Upper Rad Hose