Checking glow plugs

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ddahaa
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Checking glow plugs

Post by ddahaa »

Just found this forum and it looks like it is going to save me money already!! I've ordered a new stereo with my crimbo money and found out from here that the face plate adapters are cheaper from citroen!! Do they still have the cover?
This is my first diesel car and I just wondered how I go about checking the glow plugs?
I'm in the middle of fitting new disks and pads at the moment, didn't realise how bad my old ones had been allowed to get!!! Some kind previous owner had cut the loom for the wear sensors!!
Car is 1996 ZX Volcane TD
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AndersDK
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Post by AndersDK »

The glowplugs are simple heating elements - with low ohmic resistance - approx 1 ohm.
They are checked automatically when the engine is started [;)]
If you have start problems - especially initial lumpy running for more than some 3-5 sec's - the plugs are very suspicious.
Their normal service life ranges from 60 to 90 Kmiles.
Note that the plugs continues to glow several minutes after the panel lamp extinguishes - to ensure stable engine running and low pollution.
If the engine seems to start & run much better after prolonged/repeated glow timing - the glowplugs are then ready for replacement.
On the other hand - if you have records that the glowplugs are fairly new - you're most likely facing other problems.
ddahaa
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Post by ddahaa »

In the colder weather we have been getting recently it is sometimes slightly lumpy for the first couple of seconds. Can I check them with a multimeter then? Car has done 57k miles.
I've read the threads on tuning the TD for a bit extra performance, just wondered how many people have done this themselves or would I be better off taking it to a rolling road? Is the performance increase quite noticable?
Thanks in advance for your repies.
jeremy
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Post by jeremy »

yes - to test a glowplug simply unscrew the nut on top of the plug and remove the wire. Now test the resistance between the terminal on top of the plug and the body of the plug or the head. It should be minimal - in the order of 1 ohm or less and the same for all.
Another common source of misfiring on startup is air in the fuel caused by a loose fuel pipe. The injection pump also functions as the lift pump and so all the pipework behind is under vacuum and any loose joint or split in the pipework will admit air. Large amounts of air will stop the engine, but the odd bubble will cause misfiring. Sometimes operating the primer makes a difference in which case suspect air.
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TomH
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Post by TomH »

Some can be difficult to access to replace. I had to have mine changed recently, but they obviously had not been done for a long time, if ever! One was severely rusty and broke while being taken out meaning the cylinder head had to come off and be sent away to have the glow plug remains drilled out at great expense!
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