How to check glow plugs?

[Cheesetoast]

my car's having rough starts in the mornings when it's cold, cranks fine and starts, but sputters for a few seconds and leaves a nice cloud of smoke, after that it drives fine.  How can i test the glow plugs? it's been about 100,000km i believe.  I cycle the plugs twice to try to help it along, been around 2-6 degrees celcius here in the am

[irons]

well you could pull them out, 12v to the top of it and ground its body. If its good it will glow red in about four seconds.

[Eli]

You can also pull the injectors and with the them out you can see the tips of the glow plugs. So turn the glow plugs on and look down the injector holes to see which ones are actually glowing.

Though, this is probably more work then just taking out the glow plugs and testing them with wires. As Irons stated.

I guess the injector holes are more of a method of testing glow plugs once you have your injectors out already for some other reason.

Anyway, good luck.

-E

[jimfoo]

Or if you have individual wires on each one, just see if you get a spark when you feed 12v to each one. There should be a small spark visible when you first touch 12v to the wire.

[addautomotive]

Or if you have individual wires on each one, just see if you get a spark when you feed 12v to each one. There should be a small spark visible when you first touch 12v to the wire.

On both my cars, I've run individual wires to each glowplug. If I start having trouble starting, I can test each one individually in 5 minutes flat.

I usually just run a test lamp from the 12v battery terminal, to each GP. The light will go on... if not they are burnt out.

[gnavs]

I came across this, on Vortex of all places.  Who knew

http://forums.vwvortex.com/zerothread?id=3418051

[Cheesetoast]

Or if you have individual wires on each one, just see if you get a spark when you feed 12v to each one. There should be a small spark visible when you first touch 12v to the wire.

On both my cars, I've run individual wires to each glowplug. If I start having trouble starting, I can test each one individually in 5 minutes flat.

I usually just run a test lamp from the 12v battery terminal, to each GP. The light will go on... if not they are burnt out.

so instead of that bar across them, they are all individually connected? interesting idea.  That bar is such a pain to remove.

[addautomotive]

so instead of that bar across them, they are all individually connected? interesting idea.  That bar is such a pain to remove.

Exactly. I work on the diesels of my friends & family. Anytime a bus bar comes off in my garage, it stays off.

Each wire has a spade connector like THIS on the glow plug end:


That way, if you have to change the GP, you don't have to take the 8mm nut OFF, you just LOOSEN it. When you're putting a new GP in, you put the 8mm nut on with a gap so you can slide the spade connector in after, and tighten it.

You can't even imagine how much time this saves, not having to frig around with those 8mm nuts.

[Riverfurm]

Fast glow plugs draw 12 amps each so if you have a total draw of 48 amps they are all working,36 amps one is not working and so on.
Slow plugs draw 9 amps each for a total of 36 amps.
I use an ohm meter on each plug with the strap dissconected. If the meter show an open I know that one is burned out. I have never seen one half burn out.