How do I check glowplugs on a 6.2?

[rs74]

Can I just turn the key on and use my test light? Connect to ground and see if there is power at the glow plug? Going to start troubleshooting on the no start issue. I would like to start there that way if I need to replace then I will have a full working set to start with. And how loud is the glow plug relay/solenoid/controller on the inside fender supposed to be. It buzzes a couple of times when keyed on.

[Corts60]

I would start at that relay. If it is buzzing, the contacts have more than likely failed. It should only click once when you turn the key on.

[rs74]

Originally Posted by Corts60

I would start at that relay. If it is buzzing, the contacts have more than likely failed. It should only click once when you turn the key on.

Thanks. Answer me this. With the key off I should have power on the battery side. Now when keyed on I should have power on the other pole right? I had no power yesterday there when I tried but that was before it started to make noise. I even took off the flat connector below it and checked across and nothing. I would still like to check the glow plugs too and make sure they are good if you have any thoughts on that.

[57ToyBox]

A good glow plug will produce a small amount of resistance.
Disconnect the wire and do a continuity test. High resistance indicates a bad glow plug

[D13]

You will have power on the far side of therealy (to the glows) for 10-15 seconds after key on, with the engine cold. Best thing I ever did for the 6.2 was put a manual override in parallel. When I turn the key the old realy clicks on, I hit the override, and hold it an extra 10-15 seconds afte the relay kicks out. never had a start issue when I have fuel (next - spin on Racor filters with air bleeds and an electric fuel pump).

Best way to test glows is to pull them and activate them and look for the tip to get hot.

Absolute best thing to do is pull them and replace them with 60G's, self limiting so the tips don't burn and swell (common failure on the 9G's), then add the override and give it the extra time and it'll be happy.

[rs74]

Originally Posted by Corts60

I would start at that relay. If it is buzzing, the contacts have more than likely failed. It should only click once when you turn the key on.

Got it running today. Not sure but I think the controller was buzzing due to low batteries. After I got it running and warmed up I then shut it off. Every time after that I started it the controller just made a click. So as of right now I am chalking it up to low batteries.

[chengny]

These might help. Glow plug trouble shooting guide - from the military's CUCV manuals:

[crashz]

D13 nailed it. Couldn't be said better.

His comments on filters and fuel pump are on as well. Got my e-pump and will be installing spin on Mack filters (primary and secondary as I have a full set) for the 87.

[crashz]

BTW - if you pull/replace the glow plugs, remember they can swell and will pack with carbon. Take you time with them and do not break off the ceramic tip inside the head.

Mine came out hard on the 87 but plenty of penetrating oil disolved the carbon and allowed them to slide out. They were getting stuck well past the threads, so I was able to unthread and pullout a 1/4" before getting stuck. Pull very gently!