glow plug test

[bowhunter13]

is there a way to test these?
i hear the unit clicking on pass side of eng (small box on the valve cover)

but is there a way to test them to see if they are heating up or anything.

i looking in tech but i cant seem to find that exactly

 

[Shawn MacAnanny]

Wts light should stay on about 10 seconds before clicking 20 seconds when cold. If a plug is bad or unhooked the wts light is on much shorter. I've heard you can ohm them out but I'm not sure how accurate that is. I questioned some when I first purchased my truck and went ahead and replaced them all with zd9s. There were 3 brands in there too

 

[kcconfq]

Ohm from the spade to the block, look for less that 4. If it's open or higher you know they are bad. You can also back probe the connectors on a cold start with a test light to make sure each gp is getting power.

 

[bowhunter13]

My wait to start light is only on for a second. Then u clicks for like 10-15 seconds

 

[bowhunter13]

Do I do that with power. Ohms test

 

[kcconfq]

Ohm test is with the glow plug disconnected from the harness and cold. Do it after its set overnight, a hot plug will give you a different reading.

 

[bowhunter13]

Thanks for help,
truck sat for a day.

this am disconnected each connector and tested the GP. 4 out of the 8 had NO reading. one on passenger side has 1.2 ( the others were dead) , the drivers side was
1.5, .7 , .5 and dead. front to back.

I assume this is why it will not start.

i also test the leads for power. all had power at same voltage direct to plugs.

THANKS AGAIN, looks like i will just change them all..

 

[Tyee II]

How can I go about testing glow plugs that are out of the engine ?

 

[OLDBULL8]

With an Ohm meter, Black lead on the body, Red lead to the tip that the wire fastened to. Should read 2 to 3 ohms for a good one. An burnt out GP you get NO reading on the meter, a shorted GP will read all Zeros on the meter.

It's a good thing to replace them all if any are no good. It's recommened to use only Motorcraft/ Beru ZD 9 for a 7.3 and ZD1 for a 6.9

 

[HS108]

Ohm it, place the black lead on the body, red lead on the tip that plugs in


Whoops waited to long to hit post, and he beat me to it

 

[Tyee II]

thank you

 

[Tyee II]

I tested all 16 that I have both sets came out of trucks that didi not have know glow plug / starting issues. each plug test in a range of .7,.8 or .9 The majority were .8
The tips all look good. Based on the 2 to 3 ohms, none of these are i that range. Any thoughts ?

 

[franklin2]

I tested all 16 that I have both sets came out of trucks that didi not have know glow plug / starting issues. each plug test in a range of .7,.8 or .9 The majority were .8
The tips all look good. Based on the 2 to 3 ohms, none of these are i that range. Any thoughts ?

They are good. Like was mentioned above, if they are not motorcraft or international plugs (beru) then don't bother with them even if they are good. Some of the others are known to swell up and then they break off when you try to remove them and pieces fall down into the engine. And the controller is touchy, the reason it will not work if one or more are bad. So it's best to use the right ones.

 

[Tyee II]

Thanks they are all motorcraft/beru I will select the best 8 looking tips of which none look bad, run them thru the ohm test one more time and use them

 

[rempfer]

Wts light should stay on about 10 seconds before clicking 20 seconds when cold. If a plug is bad or unhooked the wts light is on much shorter.

Even though the weather is cold here, my 1988 F250's non-turbo 7.3 IDI wait light has started turning off unusually quickly and the relay now starts clicking immediately as the light goes out (there's no longer a delay after the light goes out before the relay starts clicking). When the engine does start, it runs on some but not all cylinders for the first 15 seconds or so at which point the other cylinders kick in. Lots of smoke during start-up so am pretty sure there's no fuel delivery problem.

Question: Is this a clear indication of one or more bad glow plugs?

Thanks.