Testing glowplugs

If you measure the voltage between the plugs (which should be mV) the voltage should step up as you get closer to the battery when they're on. e.g. 4-3 37mV, 3-2 74mV, 2-1 112mV. or you can disconnect the feed when they're off & they should be around 1Ohm to Earth.

Take them out and put a pair of jump leads on them, they should glow red within a few seconds, if not then chuck them

The message from "mrcheerful ." contains these words:

And put a thin smear of copper grease on them once out so that once replaces you stand a change of getting them out again another time.

I tested resistance on them and compared them to each other. If the engine won't start at all, I'd guess that 2 or 3 plug have gone.

"Doki" wrote in news:45646df2$0$18046$ snipped-for-privacy@news.zen.co.uk:

Engine starts ok, feels like it's missing on one before it warms. Nice plume of smoke on cold mornings :-)

Should be fairly easy then. The proper way is to check resistance as they're being heated up, but I reckon you could get away with taking cold readings, running the glow plugs, then doing hot readings. The ones that haven't changed or barely changed will be the broken ones.

Probably the most reliable test is to use a multimeter on the 10A current measurement setting, take off the busbar or wiring loom so the plugs aren't connected to anything, then hold one multimeter probe on battery +12V and the other on each glow plug tip in turn. You ought to see a high initial current, dropping down as the plug heats up and settling at a few amps. Don't know exactly how many amps but should be about the same on each.

"Vim Fuego" wrote in news:xH09h.25635$ snipped-for-privacy@newsfe3-win.ntli.net:

I'll be trying that as soon as my back will let me. Just done both driveshafts, one wheel cylinder, sorted handbrake, drop links, complete change of brake fluid, replaced all the lights in the instrument panel and centre console. I've found I'm not as young as I used to be. I used to feel like this after a bike crash, not just wielding a fecking spanner !!! :-) At least the bloody car now has an MOT, which I thought was due at the end of the month, but was actually a 'small' while ago ;-)

One of the things that doesn't help is the cold :-(

I don't see this as a glow plug problem, maybe injectors.

...or if they're a bastard to replace. Having mostly owned TUD5 diesels, on which you can replace the glowies in fifteen minutes with a fair wind, I tend to forget that on some engines they're a right bastard.

I got my eight year old to do the ones on my last AX diesel (TUD5 engine) while I watched. Seriously. Bless him, he was so chuffed with himself I even made him a Chief Glowplug Technician certificate afterwards.

"Vim Fuego" wrote in news:FW39h.54032$ snipped-for-privacy@newsfe1-gui.ntli.net:

Heh, will you do me one when I get round to it, and hopefully succeed :-) Plenty Plusgas on the car, horse liniment on me.

Then he took it up to our local Formula One and said could he have a job and they said nah, overqualified. :-)

How long do you think it takes a diesel engine to ignite the diesel through compression, without using the glowplugs?

"ThePunisher" wrote in news:9BH9h.30799$ snipped-for-privacy@newsfe7-gui.ntli.net:

At what air temperature?

I agree there is scope for ambiguity in the "before it warms" statement. Depends what's getting warm. If we mean the insides of the cylinders, then we're talking a period of a few seconds and glowplug is the obvious suspect. If we're talking the whole engine getting warm and a period of minutes, then no, that's not a glowplug.

The fact the OP said the engine starts ok, seems to me that the glow plugs work fine.

"feels like it's missing on one before it warms" so although it has started it is not running right. this is the symptom of one glow plug failed. Difficult to start and runs very rough would be two failed. Almost impossible to start and runs very rough is three, Starts on a tow is four. keep going for 5 and 6 pot

mrcheerful

Can you answer my question?

How long do you think it takes a diesel engine to ignite the diesel through compression, without using the glowplugs?