7.3 idi glow plug issues
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5th Gear
Joined: Oct 2024
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7.3 idi glow plug issues
Here’s one for the electrical wizards! 1993 f250 N/A idi, new AutoZone glow plug controller, required entire engine harness as the old controller was stuck on after shorting against the throttle cable (melted wires) used barrel connectors with springs wrapped around them to keep contact tension, traced back to GPR contact, 12.1v at the ignition switch contact, 13v at battery contact, new motor craft zd-9-1x glow plugs 1.2ohm resistance on each tested at glow plug hex to male barrel terminal. Gpr clicks repeatedly on key on like it’s already warm even when cold. Removed ribbon cable on gpr to see if it’s resistance issue, with a homemade alligator clip lead between relay and glow plug harness contact, gpr cycles normally as if nothings wrong. I’m leaning toward a bad new gpr at this point. Am I right?
Tuned
Joined: Jun 2013
Posts: 436
Likes: 61
From: Craigmont, Id
How many amps do the glow plugs draw? Where did you get the new plugs from? I am thinking you have some China plugs and they are not drawing the amperage that they should. Ask me how I know!!!!!!!!!!!!!
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5th Gear
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I got the plugs from AutoZone about 6 months ago, they better not be Chinese.
here’s the results of the load test: performed with a UEI clamp on digital volt/ammeter
each test cycled via manual relay bypass for 3 seconds
cyl 1: 9.7A
cyl 2: 9.9A
cyl 3: 10.5A
cyl 4: 9.8A
cyl 5: 10.1A
cyl 6: 10.4A
cyl 7: 10.2A
cyl 8: 9.9A
total: 80.5A
At fusible links off of relay to glow plug harness: 86.2A
hope this gets me closer to an answer, from what I’ve seen elsewhere online, the plugs seem to have the correct resistance and amp draw so I’m just about ready to toss this gpr across the counter at AutoZone and try NAPA
here’s the results of the load test: performed with a UEI clamp on digital volt/ammeter
each test cycled via manual relay bypass for 3 seconds
cyl 1: 9.7A
cyl 2: 9.9A
cyl 3: 10.5A
cyl 4: 9.8A
cyl 5: 10.1A
cyl 6: 10.4A
cyl 7: 10.2A
cyl 8: 9.9A
total: 80.5A
At fusible links off of relay to glow plug harness: 86.2A
hope this gets me closer to an answer, from what I’ve seen elsewhere online, the plugs seem to have the correct resistance and amp draw so I’m just about ready to toss this gpr across the counter at AutoZone and try NAPA
Last edited by Slopstak; Oct 22, 2024 at 10:09 PM.
Tuned
Joined: Jun 2013
Posts: 436
Likes: 61
From: Craigmont, Id
Looks about like the numbers I had when I went through the same thing. When I got OEM plugs the numbers went up to a little over 18-20 amps per plug with a total draw up around 200 amps. Then the controller went back to working correctly. Do you still have any of the packages that your plugs came in? If you do is there a small vent hole punched in the package?
i ain't rite
Joined: Mar 2005
Posts: 65,421
Likes: 5,506
From: Marlboro Mental Hospital.
agreed. 86 amp draw of 8 glow plugs in no good. you should see closer to 20 amp draw for 8.
the mass influx of chinesium glow plugs with zd-9 number on them is the reason for motorcraft to switch the part number to ZD-29
the mass influx of chinesium glow plugs with zd-9 number on them is the reason for motorcraft to switch the part number to ZD-29
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5th Gear
Joined: Oct 2024
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Looks about like the numbers I had when I went through the same thing. When I got OEM plugs the numbers went up to a little over 18-20 amps per plug with a total draw up around 200 amps. Then the controller went back to working correctly. Do you still have any of the packages that your plugs came in? If you do is there a small vent hole punched in the package?
Tuned
Joined: Jun 2013
Posts: 436
Likes: 61
From: Craigmont, Id
Same issue I had no vent hole, sorry to tell you but they are not OEM. I found measuring the amp draw was a much better test. Look for around 20 or higher amps per plug. You will find about a 100 amps per bank or around 200 for the complete system when things are working correctly. Most amp meters will not read that high. I have a clamp on induction meter that I can use with a Fluke. If you do not have a meter that will read 25 amps or so buy a 30-0-30 amp meter and use it. They are not much money and will give you a close enough idea what is going on for an individual plug. I got my plugs at O'Reilly last year but the Ford dealer was not asking all that much more. I believe $12 at O and 16$ at Ford.
This might help you some.
This might help you some.
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i ain't rite
Joined: Mar 2005
Posts: 65,421
Likes: 5,506
From: Marlboro Mental Hospital.
I would not trust ANY zd-9 plugs these days.
unless they are known to be at least 10 years old
unless they are known to be at least 10 years old
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5th Gear
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Yup they’re fake plugs
Update:
They’re definitely fake plugs, I was able to get AutoZone to give me store credit after I explained how a legitimate parts store shouldn’t have been selling chinesium counterfeit parts. They offered to order autolites, of course I declined.
Carquest was able to get a full set of ZD-29’s, they work great and I haven’t had a problem so far. There was also a ZD-9 in the mix so I scooped that one up, hopefully I can slowly gather a set of true ZD-9 spares.
Thanks everybody for the help!
PS my ammeter goes up to 1000a so it’ll do everything I need it do do
They’re definitely fake plugs, I was able to get AutoZone to give me store credit after I explained how a legitimate parts store shouldn’t have been selling chinesium counterfeit parts. They offered to order autolites, of course I declined.
Carquest was able to get a full set of ZD-29’s, they work great and I haven’t had a problem so far. There was also a ZD-9 in the mix so I scooped that one up, hopefully I can slowly gather a set of true ZD-9 spares.
Thanks everybody for the help!
PS my ammeter goes up to 1000a so it’ll do everything I need it do do
Tuned
Joined: Jun 2013
Posts: 436
Likes: 61
From: Craigmont, Id
Glad you were able to get your issue resolved. If you do not mind me asking what did you have to pay for correct ones. If I recall correctly last fall I paid $12 and change for mine at O'Reilly and Ford was $16. This was a year ago.
i ain't rite
Joined: Mar 2005
Posts: 65,421
Likes: 5,506
From: Marlboro Mental Hospital.
amazon is a know chinesium fake glow plug advertiser. they do not "sell" the glow plugs, they act as a middle mane between seller and purchaser.
there is a amazon seller moved into our old shop. they now have control of 5 of the 6 bays in the building and are expanding on average one bay every 6 months.
people buy from amazon who contacts the seller, who packages in amazon boxes and ships to buyer.
there is a amazon seller moved into our old shop. they now have control of 5 of the 6 bays in the building and are expanding on average one bay every 6 months.
people buy from amazon who contacts the seller, who packages in amazon boxes and ships to buyer.