Hello, I think I've got my learning curve under control. So what I'm looking for is confirmation that I'm thinking about this right.

I'm on a Christmas trip to Wyoming, drove 1070 miles from California without a single issue. It's not really that cold up here which is surprised (coldest even at night has been mid 30s). Truck has started every time without difficulty, but yesterday, started a little rougher and threw a P0673 code. #3 glow plug open circuit. Did a bunch of reading, pulled the plugs on the GCPM and tested each plug wire. All plugs were within the .1-2.0 resistance except #3, which measured 51.6. So although I've read that the GCPM could be the problem, it seems like based on my test that #3 glow plug is actually bad. I'd like some feedback to confirm this thought, might it still be the GCPM that is bad?

Now for some questions:

1. Can I wait till I get home to replace the glow plug, or should I do it here before I go?
2. I will plan to replace the entire passenger bank (GP 1,3,5,7) at the same time along with the GP harness. I have the part numbers, and ready to get after it.

Any thoughts, correction or advice is much appreciated as always! Thanks.

 

It's the glow plug only, and I would wait until you get home if you are doing it yourself.

Is there some risk to that? Yes. The tip may be hurt. But not only will the harness be a problem, and I would expect to need to replace it, but if the tip is swollen, it's not a simple task.

If you are considering having a shop or dealer do it, I would probably do it there. They would have the warm bay and tools to deal with whatever happens.

 

thanks!

might it mitigate the potential swollen plug if I use the block heater everyday while I’m here?

also, am I thinking right about doing the whole side at once?

 

If I were in your shoes, knowing you will probably have to replace the harness anyway, I'd cut the feed wire to that glow plug and let the 7 others do their job. Glow plugs are cheap; I'd do all on that side. Take the valve cover off and put rags at the oil drain back holes in the head so the little pieces that will break off from the harness won't go into the engine. Not that it's a big worry being plastic, but it's less that will be on your mind in the future.

Get the OE Motorcraft (BERU) glow plugs from Tasca, Lakeland, or RockAuto.

 

I guess I didn’t think that the valve needed to come off. I watched a video from DieselTechRon showing how to replace passenger side glow plugs. What’s the reason for removing the valve cover?

 

There is a good chance that the harness will break apart and debris will enter the engine. Me, I'd rather not do that. Or follow DTR's methodology.

 

Definitely don’t want stuff falling into the engine, just trying to understand how removing the valve cover prevents that. Thanks!

 

By plugging the oil drain back holes.

 

+1 with Jack on waiting until you get home. One cylinder shouldn’t be an issue at all. Use the block heater when you can. Let the other glow plugs cycle longer before starting. Just because the glow plug dummy light goes off on the dash doesn’t mean that they’ve stopped heating. The dummy indicator is just a timer.

 

I did all of the left side glow plugs and a harness a couple of months ago. The easiest way to access is removing the fender liner. All of my electrical plugs fell apart upon removal, glow plugs were the easy part. The harness on the left side plugs in near the FICM and requires items to be removed for access. As suggested, wait until you get home if you are doing it yourself.

I have been on many long trips in my Ex, these things happen, fortunately you are not experiencing an issue that needs to be addressed right away. I had a crank sensor code pop up on my last trip, I addressed this immediately on the side of an Autozone in Wilcox, AZ knowing it could shut me down on a remote Western highway.

 

What year is your truck? Note that 03 and early 04 use a different glow plug and harness. Late 04 & later I believe are all the same.

The connectors can be a bear to get out. Recommend you watch some Youtube videos. You'll be doing the passenger side for #3, I'd recommend pulling the fender liner, its really easy on that side (driver side is not). Also get the special tool for the harness, it's not expensive and makes it much easier (still not easy).
https://www.xtremediesel.com/lisle-3...MaAqH7EALw_wcB

 

With respect to the glow plugs, there are 3 varieties in 2004 (buss bar for early ones (same as '03), early harness, late harness (same as '05 and up)):


'03 (buss bar):
3C3Z-12A690-BA
3C3Z-12A690-AA

Early '04 (FROM 08/17/03 to 01/15/04):
4C3Z-12A690-AA
4C3Z-12A690-BA

Late '04 (01/16/04 and later including '05):
4C2Z-12A690-AB
5C3Z-12A690-A

Note that for the later '04 drivers side, there was a version that ONLY fit the late '04, and not the '05's - part number 4C2Z-12A690-BA. Best to use the '05 part number IMO.

 

My Excursion is a 2004. Building date 4-19-04, I think that makes it a Late-Late 04.

 

Just verify the orientation of the GPCM (vertical or horizontal). As we all know - the Excursions got some engine left-overs that last year.

 

Indeed, GPCM is vertical.