Motorcraft ZD-29 Glow Plugs

[lakesurfer]

Time to do GPs and saw the lack of ZD-9 availability and the controversy about ZD-29s, so I thought I'd try them and start a thread.

I bought 8+1 from Rock Auto to minimize the chance of counterfeits. They came in individually sealed Ford Motorcraft bags. The bags say, "Made in Germany". The plugs not say "Beru" but the one I looked closely at had the following legit-looking markings:
ZD29
E2510 061143
2216
10.5V

Most importantly, all 9 measured either 0.1 or 0.2 ohms.

2019 was the last time I replaced the set, and now I have the dreaded relay clicking so it's time to replace them. We shall see how the ZD-29s do.

 

[Brian VT]

Subscribed...thanks for doing this.

 

[lakesurfer]

Bottom line: After 8 new (and verified) ZD-29 plugs and with a 37 degree temperature, the truck glowed a solid 15 seconds and started easily like it was a summer day!

None of the old (2019) plugs were open or swollen, but they measured all over the place and two were unstable. No wonder the controller threw in the towel.

I will update this thread if something noteworthy happens.

Here' the data:

Cylinder : plug resistance (ohms)
2 : 0.8 - 0.1 (too unstable IMO)
4 : 0.7 - 0.2 (too unstable IMO)
6 : 0.2 - 0.1 (seems OK)
8 : 0.0 - 0.1 (mostly 0.0 so too low IMO)
1 : 0.0 (too low IMO)
3 : 0.0 - 0.1 (mostly 0.0 so too low IMO)
5 : 0.1 (seems OK)
7 : 0.2 - 0.1 (seems OK)

 

[tbowker]

with a 37 degree temperature, the truck glowed a solid 15 seconds and started easily like it was a summer day!

It doesn't often get that cold in my neck of the woods, but the low 40s are not unheard of. I have the GP controller delete and with an 8 second count at 42 degrees the engine starts in less than two revolutions. I question whether 15 seconds is excessive, I would think it contributes to an early demise for the GP's.

Here' the data:

Cylinder : plug resistance (ohms)
2 : 0.8 - 0.1 (too unstable IMO)
4 : 0.7 - 0.2 (too unstable IMO)
6 : 0.2 - 0.1 (seems OK)
8 : 0.0 - 0.1 (mostly 0.0 so too low IMO)
1 : 0.0 (too low IMO)
3 : 0.0 - 0.1 (mostly 0.0 so too low IMO)
5 : 0.1 (seems OK)
7 : 0.2 - 0.1 (seems OK)

Thanks for this info. What kind of meter and model did you use to get these readings?

 

[Bart F-350]

what's it about a clicking relai gives it's time to replace the plugs?
My plugs are still from 1989, and sometimes I see the voltmeter needle spring around when glowing, but it still starts???

 

[reset2]

"ZD-9 availability and the controversy about ZD-29"
I have only used the ZD-9 before what is the difference of the 29's?
Yes I had the same clicking thing going on before and found at least 3 bad.
Have you had the issue with the two wires going thru the connector block melting open. I found that one will burn open (wire feeding the controller) then the other will overheat and fail also because of the excessive current flowing.

 

[lakesurfer]

@Bart F-350
Clicking (pulses of glow) *after* a decent amount of "Wait To Start" (solid glowing) is normal I think. In my case, there was only a blink of "Wait To Start", then just clicking.

The parallel resistance of the glow plugs changes as they heat up. This is how the controller 'knows" how long to glow in different temps. If a plug fails, or if several are out of spec, it fools the controller into glowing too little, not glowing at all, or just pulsing.

There's more to it but that's the overview answer.

 

[lakesurfer]

"ZD-9 availability and the controversy about ZD-29"
I have only used the ZD-9 before what is the difference of the 29's?
Yes I had the same clicking thing going on before and found at least 3 bad.
Have you had the issue with the two wires going thru the connector block melting open. I found that one will burn open (wire feeding the controller) then the other will overheat and fail also because of the excessive current flowing.

@reset2
Could not find any info about the difference between then. Based on availability, it seemed clear it is Ford's standard going forward.

If these fail I'll go to one of the alternate non-standard GP solutions others have documented.

 

[lakesurfer]

It doesn't often get that cold in my neck of the woods, but the low 40s are not unheard of. I have the GP controller delete and with an 8 second count at 42 degrees the engine starts in less than two revolutions. I question whether 15 seconds is excessive, I would think it contributes to an early demise for the GP's.


Thanks for this info. What kind of meter and model did you use to get these readings?

@tbowker
"15 seconds" I didn't us a stopwatch. I was too overjoyed just to see it work. Mighta been only 11.

Meter: My fluke died and I bought this China meter because it also measures large DC current (not 200A tho) at a reasonable price.

UNI-T UT210D Digital AC/DC... https://www.amazon.com/dp/B0753FY711?ref=ppx_pop_mob_ap_share

 

[IDIBRONCO]

I question whether 15 seconds is excessive, I would think it contributes to an early demise for the GP's

I agree. I only glow mine for 8 seconds. Now when I switch to the Bosch glow plugs, then I'll start out at 15 seconds and go from there. The Bosch plugs take longer to heat up.

I have only used the ZD-9 before what is the difference of the 29's?

From what I've seen on here, the only difference is "supposed" to be that the 29s come in a 2 pack instead of single.

 

[lakesurfer]

From what I've seen on here, the only difference is "supposed" to be that the 29s come in a 2 pack instead of single.

@IDIBRONCO This was not my experience. All my ZD-29 plugs were individually packaged.

 

[IDIBRONCO]

@IDIBRONCO This was not my experience. All my ZD-29 plugs were individually packaged.

Well I guess that info was wrong.

 

[Black dawg]

Well I guess that info was wrong.

Have seen them both ways now. Have a bunch of the two per bag, and now have been getting them that are singles

 

[jbm6900]

I used to test em, till I found the Only reliable glow plug test, no matter brand, is to pull it, hook a 12vdc jumper to it, touch the threads to ground & you'll know right away if it's good or not... More than one, change em all.

 

[jbm6900]

It doesn't often get that cold in my neck of the woods, but the low 40s are not unheard of. I have the GP controller delete and with an 8 second count at 42 degrees the engine starts in less than two revolutions. I question whether 15 seconds is excessive, I would think it contributes to an early demise for the GP's.


Thanks for this info. What kind of meter and model did you use to get these readings?

I ran a momentary toggle in mine for yrs in FL, i'd do a 5, maybe 10 count depending on temp., Plugs & controller lasted MUUch longer manually, don't need use em alot down here.