2003 F250 7.3l glow plug testing
 

What ohm resisitance should I be looking for when I test my glow plugs? Gonna do it tonight if it's not raining. Thanks a bunch

A quick check with a digital ohm meter at the GPR, between large lug towards the drivers side & ground, with the key off should read 8 to 9 ohms..if the of the glow plugs are good..Also, check the voltage with the key on on a cold start, should read about 10.5 to 11 volts if the system is working properly.. You can also check each of the glow plugs individually at the valve cover connector..with the following :

GGIICIIGG
G - Glow Plug
I - Injector +
C - Injector -
Ohms between the G and block Ground should be 0.1 - 2.0 ohms.
Ohms between the I and C one at a time if one or more is > 5 ohms, it will point to the side's gasket connector or UVC harness being shorted.

Thanks. I hope that is what I need to figure out what needs replaced.

Thought it was .5 to 2.0 ?

Mine was about 1.5 across the board except one, one was something like 16.5.. I installed all new ones.

And checked ohms with my snazzy tool i whipped up. Attachment 230062

Wanna loan that thing out? I'm gonna have to hire somebody to check it out. All that ggiccgg stuff is confusing and I know I'll fark something up. I'll send it back I promise. :-X06 I only wish that I could build something like that.

You really need to do this stuff yourself.. we are here to help every step of the way..
There is lots of experts here on the forum.. We were all in your shoes not too long ago..

I really don't have the tools for one and my ASE certified brother would rather hang out with the wicked witch of the west than show me how.

I do have a multi-tester but I have no idea of what to do. Way more complicated than my sled or bike.

Can somebody please explain how and where I can check my GPs at the connector outside of the valve covers? Maybe some pics and where I need to poke the meter probes?

I hate to sound stupid but I want to make sure that I do it and do it right. Honestly I don't understand the GP to Ground, injector+ to injector- and so on.

Here's a start for ya.

https://www.ford-trucks.com/forums/7...pr-system.html

https://www.ford-trucks.com/forums/8...ck-shakes.html

Good luck

Like I mentioned in my post #2 above.. 1 st take your ohm meter.. put it on "resistance" at a low range .. Put the black negative probe on the negative battery lug and the red probe (+) to the large lug towards the drivers side of the glow plug relay, with your ignition key off...(see my gallery pictures).. If the reading is around 8 or 9 ohms, your glow plugs are good.. If not, then you can go check the valve cover connector to check each individual glow plug.. using the GGIIcIIGG method that Dean gave you above in the two links.

Repeat post, But in a different way.

Unplug the connectors at each valve cover.

Put the meter on the OHMS setting.
Clip the black wire of the meter to the negative battery. (so it stays there by itself, using a battery cable clamp)

Take the red wire of the meter and touch every pin in those connectors and report back of the readings you get on the meter. Left to right. We can take it from there once you post the readings.

Tough to see those pins. But doable. May need a helper to read the meter and write down the reading.

I surely can loan out my contraption, But shipping coast will kill you. I made that so i can take the reading without laying on my stomach and it is 100 x's quicker. But you don't really need it.

Can you send me instr. on how to make one myself? That would be awesome.

I checked the GP prongs (front 2, back 2) on each side. The passenger side read 1.2/1.6 ohms on all four. The driver's side was the issue. the first 3 prongs didn't even register a reading but the last one (closest to the cab) read the same as the other side, 1.2ohms.

Looks like you have three dead GP's on #2 cyl and #4 and #6. Driver side front three gp.s

Wow. Three dead ones. Maybe time for the 50 cent mod. Wonder if the harness has come unplugged inside the cover I would check again to just say you double checked.

I will work up instructions on the box. Have to refresh my memory. Have to warn yea though. The connectors were the most expensive part of that job. I don't remember exactly but i think they were like $40. It will also check injector ohms.

That's is my thinking.

50 cent mod?