After the glow plug and UVC harness R&R yesterday she was running great. Today I towed my boat for about 100 miles. Got home and was backing into the garage and the SES light came on and the horrible idle came on again. Unhitched and went for a test drive to see if I could figure it out.

It would go away after a restart but come back. No consistency to it but THIS time the light stayed on once. I pulled the ICP pigtail and the idle smoothed out.

Yesterday when I was testing it and put the new sensor in, I'd also used electrical cleaner on the pigtail but noticed the sensor was oily. Since the new sensor didn't fix the problem, I put the old one back in (fix or replace one thing at a time, right ??).

So I **HOPE** that since it still leaks oil through the sensor and it got the pigtail, that it screwed up the VREF and that caused my problem.

I'll put the new ICP sensor it and clean up the pigtail and see if that fixes it.

 

Sounds like you've done a good job of working on isolated issues one at a time. I hope the sensor is the issue. I guess you don't have AE to track injection pressure, do you?

 

no I don't have AE. I put the new one in and ran it and it ran great - maybe it's in my head but it actually seemed to run better and my HPOP pressures I think were higher.

 

I would expect that if the ICP sensor was beginning to fail by giving erratic readings, then replacing it with a new sensor would level out those signal issues and the overall engine would run better.

I suspect that the bad sensor was affecting the way the engine ran well before the symptoms were strong enough for you to notice. When I had to replace the IPR in my wife's Excursion last year, it seemed to run lots better overall with the new unit, and probably for the same principle.

 

You might go ahead and replace the ICP pigtail. I think I paid $40 at the dealer for mine. I would strongly suggest soldering the connections or using shrinkable butt connectors. Some times the sockets in the harness get opened up and make intermittent connections. Mine did this after doing the 10K mod before I got my DP.

 

I've had something similar happen to me a while back. In the end it turned out to be a burned center pin on the UVCH. It was super hard to see, in fact I couldn't spot it until I pulled the harness and gasket from the engine and held it up to some bright sunlight. Then I saw the burned areas...

Luckily by that time I had a set on order from Riffraff. Interestingly enough, the burned center pin was on the bank that had a loose harness about a year prior. I am not sure if that caused the burned pin or if it was two isolated issues...

Just an FYI and something to check in case you continue to have problems (which I hope you do not....)