A Cautionary Tale (IPR Plug)
I'm in the middle of replacing my oil cooler, and deleting the egr cooler on my '04 6.0. Right before I started this tear-down the truck started running like hell. It was surging (really bucking) really bad. At stop lights the thing would be like a dog pulling on his leash trying to go forward. The trouble codes pointed to the ICP Sensor. "Oh Great" I thought, another $100 into the money pit.
Before I ordered the new ICP sensor, I pulled the plug to it out and thought I'd inspect the wiring. I had read that the wires go bad, and saw that there were repair kits for the plug. When I pulled of the fireproof sock on the connector and inspected the plug I was happy to see that it looked like the previous owner had already had the plug changed and the new wiring still looked good. Well, I guess I wasn't really happy, since the wire kit was a heck of a lot cheaper than a new sensor. Anyway... So, I tore into the top of the engine, and got the sensor out and put in the new one I just got in the mail today. I'm still waiting for some other parts for the project, so I was bored. I decided that the joint where the IPR plug branches out from the harness it shares with the ICP looked ratty, and I would re-do it.
Well... one thing led to another and I ended up taking off all of the heat-shielding and wrapping from both the IPR and ICP leads. And boy am I glad I did because I found something VERY interesting. Sure enough, the wires going to the ICP sensor were melted together and shorting out, but not down by the plug, but rather up by the joint where the IPR branches out. That's maybe 6-7" away. I would have NEVER looked there if I wasn't bored. I would normally have just assumed the sensor was bad, buttoned everything up, and then pulled my hair out when the truck still ran like crap after all of the work!
So, the moral of the story is, check your wire harness! Especially you guys with the older engine that has the ICP sensor in the rear of the engine!
Attached are two pics. The first shows the replacement plug splice at the end. The other zooms in on where the wires where melted together.
Since the wires looked okay, and the rest of the insulation wasn't that bad, I wrapped each wire individually, then bundled together, then insulated, then fireproofed them! And I'll be sure to zip-tie, or otherwise secure them as far away from the exhaust as possible. Oh, and I went ahead and installed the new ICP and a new IPR because I don't every want to do this again!
PS, if anyone needs any pictures of something on top of the engine, just PM me.