Diesel misfire

I go with 1 or 2 dead glow plugs as first port of call..

Mark

One dead glow plug. (assuming its missing on the same cylinder at cold start)

Tim..

I agree with the two posts above: Most likely to be glowplugs.

If it smoothens out after say 60 seconds of running or a several sharp pokes of the accelarator pedal it's most likely plugs.

-- James

It starts ok and it'll only misfire once (Maybe twice) before everything corrects itself. Wouldn't a duff glowplug cause a worse misfire and make the thing really difficult to start?

I'll test the glowplugs at the weekend and report back..

sPoNiX

Presumably I can get a good idea whether they are faulty by doing a resistance check?

I assume glow plugs go open circuit when they fail?

sPoNiX

No, not always. Only sure fire way is to pull them out and hook to 12v and see the tips go to cherry red within about 4 seconds of heating..

Tim..

It's a bad idea to hold them in your fingers when you're doing this test.

-- James

Just replace the buggers, i fitted a set to my ex's pug 106 with the 1.5 diesel engine, halfords brand.. about 15 quid a set of four,

That car had 2 dead plugs, and was fine all through summer, but was getting rougher on start up as the colder weather came in,

Glow plugs can last anything from 30k miles to 60k or more, so if the car's done any of these mileages, and you have no proof that the plugs have been changed before, they will be over due replacement.

Some vehicles flash the glow plug light if it detects a problem (my van does this.. (Iveco Turbo Daily) it's direct injection so dosent need glow plugs to start.. but it has a thermostarter.. basicaly a fith injector with a glow plug in it to spray warm go juice in the inlet manifold.. the system only works when the engine is below about 2 degrees C, and as i was trying to trick it inot powering the thermostarter system up.. i found out a slow flash of the glow plug light means no power to the relay (i'd pulled the fuse) a fast flash means the plug has gone open circuit (i had taken the supply lead off the plug) and so on.

An indirect engine with a glow plug per cylinder may not be able to show a code for a couple of failed plugs.. unless it monitors the current.. my last van only flashed the light if one of the fuses went open circuit.. or 3 plugs failed at once on the same bank (engine was a 6 cylinder)

Glow plugs are just another item most diesel owners havent got a clue ever need replacing, bit like the injectors, by about 60k miles they are past their best, and if you take them off the car before the engine starts running bad, they can usually have new nozzles fitted for about 20 quid each.. as opposed to anything upto 90 quid per injector if they are too far gone, and you'd be surprised at the performance and economy you get back from fitting injectors that are attomizing properly.. they wear over time so you get used to it and don't notice the vehicle isnt performing as good as it used to.

Injector pumps wear too, i have mine re-calibrated every 100k miles regardless, costs me 100 quid for a full re-calibration and replacemebt of the common seals that go.. paid a bit more for my iveco's pump as the throttle shaft wears out on these.. so i had it replaced as a precaution, again much cheaper to prevent problems than fix them.. and the others the part failing causes.

My ZX has been showing these syptoms for a while now, and at 82k i'd have expected to change the plugs. However at the last service at 76k the garage checked them and pronounced them fit. That threw me, a garage say there was no need to do the work requested?!?! Perhaps I'll force them to this time!

The clutch is starting to feel a bit "dry" no that's not right, the clutch action feels ever so slightly juddery in operation, not clutch take up, but te actual feel through the foot as you press the pedal down and let it up. Is it wise to get the cable changed and are they renowned for snapping on the ZX?

Cheers,

Jon.