glow plug test

[hayesash]

I was having trouble with cold starts. I tested the drivers side with a test light and it lit with all of them. With a digital ohmmeter three ranged from .8 to 1.2 while the third read 23.1. Pulled this one and hooked up to a battery charger. It became hot to the touch but no color at all. I won't be trusting a test light again.

Yes they are QH. About 6 to 8 months old. Hope this helps.

Pat

[taznj63]

I changed all of my glow plugs to QH and they did burn out. After 6 months I lost 5 of them. I bought a new set and replaced them with a new glow plug controller. My controller was staying on alot longer than the 10-15 seconds and was cycleing with long glow times.
The new controller cycles for 12 seconds then pulses about 1-2 seconds every 5 seconds or so for about 30 seconds.
I had this done mid january and during the coldest day about 8 degrees I tried to start it and did not use the block heater and she fired right up, no problems...
So If you are burning out glow plugs, check the controller, it may be bad...

[DaveNY]

Ditto: but I chucked the QH for a new set of 60's and its been kickin off like spring. Don't know if controller was the cause of several QH failures but was not willing to experiment and do the replacement job a 3rd time.
Dave

[damork]

I've never used the QH glow plugs and have had good success with 60G's. I agree with replacing the controller - first time I needed new plugs I also needed a controller. The glow plugs themselves were not the full solution.

Just finished installing the second set of 60G's after 160,000 miles and included the controller/relay as well. It's been firing off on all 8 down to 0F with no block heater (no choice at work), injectors have 167,000 mi on them, injection pump has 128,000 miles. I credit Stanadyne Performance formula & DSG gears for the long life and great starts.

[TurboDiverArt]

I've wondered the proper way to test glow plugs (while still on the truck). My truck seems to start fine in single digit temps (no block heater) so I'm inclined to not touch anything (at least 100K on them). Even with 6-year-old batteries!

Is the proper way to test them with an Ohmmeter checking resistance? If the resistance is low then the plug is good, if high to infinite it's bad? Checked from the spade to block/ground?

Thanks,
Art.

[JohnC]

The test light test is the simplest test and will give the corrrect results 99 44/100% of the time. That one high resistance plug was a fluke. My guess is that you could have seen the light was much dimmer on that one, but if you weren't looking for it, you might easily miss it. OTOH, if your plugs are flukes, you ought to use a Fluke meter to check them, doncha think? ;)

[hayesash]

You are right on it being dimmer. Without the luxury of a shop and in freezing temperatures as soon as the light went on I moved to the next one. In my basement is where I checked a new one against the bad one. Much warmer down there. I think I will still use an ohmeter.

Cheers Pat

[TurboDiverArt]

The test light test is the simplest test and will give the corrrect results 99 44/100% of the time. That one high resistance plug was a fluke. My guess is that you could have seen the light was much dimmer on that one, but if you weren't looking for it, you might easily miss it. OTOH, if your plugs are flukes, you ought to use a Fluke meter to check them, doncha think? ;)
With the test light, are you turning the key on and testing the light to ground? I would think that if the glow controller is sending power you'd light a test light every time. Or, are you putting the test lights ground clip to battery power and touching the glow plug spade. If it lights then the plug is completing the circuit to ground? If not then the plug is bad. I assume it's the second option?

Art.

[DennisG01]

Yes, you're correct. Battery + to spade connector (with the plug wire disconnected, of course!)