She swallowed a glow plug

[94NAIDI]

Nope. But the plugs that came out of the truck that supposedly hadn’t been replaced in years, still looked pretty good. I pulled them out when I bought the truck and put new ones in thinking I was doing a good thing. Guess I should have left those ones alone. Anyway, I am happy to check the timing of it could be an issue. The truck seemed to run and start pretty darn good.

 

[94NAIDI]

Well. It’s been forever and I apologize for that. I got the motor all back together. Even replaced the radiator core support while I was at it. Do to rust. Put all new glow plugs and Motorcraft controller in the truck. Put everything back together and has been running great ever since. Until today I started getting a clicking glow plug relay and hard start. Ran a quick test and sure enough, I have one bad glow plug. Held my breath as I pulled it out. Didn’t want to go through another engine pull and partial rebuild again. Glow plug came out and I replaced it. My question is, what could possibly be causing my glow plug issues. These things should be lasting more than a couple months.

I’m tempted to do the manual glow plug control modification. But I was hoping to keep everything working as it’s supposed to. That’s why I went with a brand new Motorcraft control module and new ZD-9 glow plugs.

Anyone have any ideas why my truck likes to burn out glow plugs. Possible timing issue?

 

[KansasIDI]

Well. It’s been forever and I apologize for that. I got the motor all back together. Even replaced the radiator core support while I was at it. Do to rust. Put all new glow plugs and Motorcraft controller in the truck. Put everything back together and has been running great ever since. Until today I started getting a clicking hole plug relay and hard start. Ram a quick test and sure enough, I have one bad glow plug. Held my breath as I pulled it out. Didn’t want to go through another engine pull and partial rebuild again. Glow plug came out and I replaced it. My question is, what could possibly be causing my glow plug issues. These things should be lasting more than a couple months.

I’m tempted to do the manual glow plug control modification. But I was hoping to keep everything working as it’s supposed to. That’s why I went with a brand new Motorcraft control module and new ZD-9 glow plugs.

Anyone have any ideas why my truck likes to burn out glow plugs. Possible timing issue?

I am convinced that they don’t make a quality glow plug for these engines anymore. I also had many issues, even switched to manual and still no luck. They just die fast. They’re junk.

I deleted mine.

 

[94NAIDI]

I deleted mine.

Now you have my curiosity sparked. How does one “delete” their glow plugs? I mean, you can obviously disconnect power to the harness and essentially render the system obsolete. But how do you get around the cold starts?

 

[KansasIDI]

Now you have my curiosity sparked. How does one “delete” their glow plugs? I mean, you can obviously disconnect power to the harness and essentially render the system obsolete. But how do you get around the cold starts?

I removed my glow plug wiring harness

I replaced my glow plugs with these

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That way I don’t have to worry about glow plugs falling apart in the motor. These plugs also lower the compression some due to the fact that they do not stick into the prechamber nearly as much as the glow plugs. These plugs are the same thread size and pitch as the glow plugs.

I use starting fluid, in moderation.

I am aware some people are against the use of ether.

 

[1mouse3]

I removed my glow plug wiring harness

I replaced my glow plugs with these

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That way I don’t have to worry about glow plugs falling apart in the motor. These plugs also lower the compression some due to the fact that they do not stick into the prechamber nearly as much as the glow plugs. These plugs are the same thread size and pitch as the glow plugs.

I use starting fluid, in moderation.

I am aware some people are against the use of ether.

Thats for the part number, they might work out better than what I came up with. How well do you think that o-ring will hold up?

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Now you have my curiosity sparked. How does one “delete” their glow plugs? I mean, you can obviously disconnect power to the harness and essentially render the system obsolete. But how do you get around the cold starts?

A grid heater can be made to work...

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[KansasIDI]

Thats for the part number, they might work out better than what I came up with. How well do you think that o-ring will hold up?

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A grid heater can be made to work...

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I think the O ring will be fine, the top of the holes are tapered, and I have them plenty tight. No issues so far…

 

[94NAIDI]

Hmmm. I’ve never tried ether. My truck does start great when plugged in. Even with bad glow plugs. But that only works if I’m at home.

Delete is an option. But I’d prefer to get the glow plug circuit working if at all possible. Then maybe delete as a last resort.

I’m curious if doing the manual glow plug control mod would be the solution.

As long as the cause of the glow plug failure is the glow plugs staying on to long and isn’t caused by the combustion temps.

I don’t have a way to set injector pump timing. When I “rebuilt” the motor. I did mark the original pump location and made sure it went right back to that spot. Assuming it was set right to begin with. This was also an exact alignment with the timing line etched on the pump. I read in here that you can typically advance about 1/16” from there as a general rule. So I did do that Friday. Seemed to smooth out the idle, less cackle at idle, and gave me slightly more power. That’s why I’m starting to question if there is even more timing adjustment to be had.

 

[IDIBRONCO]

I think the O ring will be fine, the top of the holes are tapered, and I have them plenty tight. No issues so far…

I think that the threads should seal up most of the compression before it gets to the o ring.

I’m starting to question if there is even more timing adjustment to be had.

Most likely yes.

As long as the cause of the glow plug failure is the glow plugs staying on to long and isn’t caused by the combustion temps.

There is also a large number of copy Motorcraft glow plugs. If you got some of those, they probably won't hold up as long as the genuine ones will.

 

[94NAIDI]

I did hear about the fakes. The only way I know is to look at the crimps. But of course, by now, the counterfeits could have learned the crimp trick as well.

 

[KansasIDI]

I did hear about the fakes. The only way I know is to look at the crimps. But of course, by now, the counterfeits could have learned the crimp trick as well.

I haven’t even had luck with the genuine Motorcraft plugs. Have heard that if you switch to manual control, Bosch 80034 self limiting glow plugs are the deal. I personally have never tried them, have only heard good things about them though.

 

[1mouse3]

I think the O ring will be fine, the top of the holes are tapered, and I have them plenty tight. No issues so far…

I think that the threads should seal up most of the compression before it gets to the o ring.

Thanks, and the taper will not be there since drilled them to fit 60g plug but could still work.

Delete is an option. But I’d prefer to get the glow plug circuit working if at all possible. Then maybe delete as a last resort.

I’m curious if doing the manual glow plug control mod would be the solution.

I haven’t even had luck with the genuine Motorcraft plugs. Have heard that if you switch to manual control, Bosch 80034 self limiting glow plugs are the deal. I personally have never tried them, have only heard good things about them though.

There is also the option of self limiting 60g plug off a 6.5, there shorter so something needs done. I had them on my 6.9 and had no issues running them manual for 10-15 seconds, I ground down the hex some to fit on that set and drilled out the holes a touch on my 7.3 heads.

 

[ttman4]

I don't know what to do anymore.
('94 Factory IDIT with manual push button)

I put in set of "Genuine" Motorcraft ZD9 glow plugs about 1000 mi back & already got couple or more not working when I tested them with my lite tester. Haven't pulled them yet cause couple very hard to get to to pull.

Just don't know what to do anymore!!!!

I haven’t even had luck with the genuine Motorcraft plugs. Have heard that if you switch to manual control, Bosch 80034 self limiting glow plugs are the deal. I personally have never tried them, have only heard good things about them though.

What is this Bosch 80034 self limiting glow plug? Seen something before about it..... need to do some more looking when I get time.

 

[FrozenMerc]

I have burned through every brand of glow plug out there, none seem to be any better than the others. I just replaced the AC Delco's in my '85 last weekend, they were less than a year old. At least none of them swelled or broke off.

That said, there is a theory that originated in the deep, dark, moist fever swamps of the internet that postulates that today's glow plugs have longer tips on them in order to simplify the manufacturing process and get more usability across multiple engine platforms for the same part number / tooling. Because of this, the tip is now centered under the injector nozzle and gets a more direct fuel spray, causing very high burn temps about the plug tip, and eroding / damaging the plug much faster.

If any one has an OE plug from the 1980's rolling around in the bottom of a cabinet / toolbox to measure against whatever your local parts house is stocking, we could test this out. Either way, the theory makes sense to me and I wonder if a simple fix would be to put a small spacer under the glow plug head that pulls the tip back, approximately a 1/4" to 1/2".

Maybe I need to fire the lathe up and get to work....

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[94NAIDI]

That’s a very interesting theory. I have no point of reference to the older original plugs. But I can definitely tell you the tips on mine are getting burned and even swelling on these supposedly Motorcraft glow plugs. I purchased them from Rockauto. I was assuming Rockauto would have good counterfeit parts avoidance procedures. But who knows.

I definitely need resolution because I cringe every time I have to remove one. Which seems to be about every two to three months. If you read the beginning of this thread you know why. A simple glow plug replacement turned into pulling the motor and basically doing a mini overhaul on it. Not something any of us want to go through again.

I’m seriously considering a manual switch and these Bosch glow plugs mentioned above.