Poorly ZX Volcane TD... (Cold Starting Probs...)

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Crossman
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Poorly ZX Volcane TD... (Cold Starting Probs...)

Post by Crossman »

Hi,
I am having a spot of bother with my ZX TD. When I try to start the beast from cold it starts on 3 cylinders and then reving it for a bit (about 20 secs) will intermitently run on 4 cylinders before reliably running on 4 cylinders. I changed all four glow plugs last year (about this time with proper Beru items) and cured a similar problem then. The strange thing before was that when I reved the engine to make it 'catch' on four cylinder it would then run on four when returning to idle straight away. This time when it catches on four cylinders at say... 2000rpm, when returning to idle it starts running on 3 cylnders for a bit before running on 4 again. Once the engine runs at tick over on four cylinders it will behave and run sweet as a nut indefnitly. I have done a bit of diagnostic with the multimeter and found the following results:
Voltage across battery after a night of standing = 12.1 volts
Voltage while glowing across battery terminal = 11.7 volts
Voltage across glow plugs when glowing = 11.6 volts
Voltage once car is running but glow plugs still glowing = 14.1 volts
Voltage once car is running with no glow = 14.3 volts
In addition to this I can clearly hear the glow relay clicking in and out strongly so I think the electric side of it is ok.
I recon it looks like either a broken glow plug (or poor connection to a plug) or could it be a leak off pipe problem? I have looked round the area and whilst it looks fairly dry around the injectors there is a leak from the rocker cover gasket so it might be disguising a problem.
What is the best way to check to see which is the failing glow plug \ injector? Disconnect the wire going to the each glow plug in turn and see if it starts on 2 cylinders rather than 3 and I will know I have reached the failing on when it starts on 3 with the wire disconnected or should I check for resistance accross each of the glow plug?
Obviously with winter on its way I am wanting to get this sorted out sharpish as I don't fancy getting left in the middle of no-where with a car that wont start [:(]
Thanks again for any help...
Crossman.
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AndersDK
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Post by AndersDK »

You say you've checked the voltage over the glowplugs while timed before engine started.
How did you actually measure this voltage ?
try read this thread :
http://www.andyspares.com/discussionfor ... IC_ID=4180
You should do the voltage check on each glowplug as described - there MAY be a chance of a dodgy cable.
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Post by Dave Burns »

The most efficient way to find a lame cylinder is to deprive them all of their fuel one at a time, the lame one will be the one that does not cause further deterioration of the idle when its fuel is cut off.
The presence of the overhead intercooler make this just about impossible on the ZX at the injector unions and its not safe to run the engine with it removed, it can however be done at the pump, counterhold the delivery valve (the bit that screws into the pump)to prevent it unscrewing while loosening the pipe union, have a good wad of rags to catch spilt fuel and be carefull of fuel spray.
If you don't fance that I would check the resistance of the plugs and make sure the plugs are correct for the TD, non td plugs even if they are Beru are not the same, older Beru TD plug number GN 909 later GN 013.
Dave
Crossman
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Post by Crossman »

Anders,
I checked the voltage between the negative side of the battery and the glow plug electric rail that feeds the glow plugs, I also did it against the point on the relay and it was the same voltage. I am going to take the electrical rail off at somepoint today and measure the resistance across each plug to see if there is anything obvious and then failing that will crack the injectors at the pump.
The thing that is making me look towards the fueling is that before (with the glow plug prob) once the engine had caught on 4 cylinders when reving, on returning to idle it would run on all four, this seems to be more time dependant, i.e. it will catch after x seconds of reving and then x seconds of idling which gives me a gut feeling of air in the fuel system.
Still... I shall don my overalls once more and have some fun [:-(] once again with the wonderful world of cars...
BTW - Does anyone know if the leak off pipes from andyspares is all of the pipes needed (5 if memory serves me) to replace the lot?
Crossman.
jeremy
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Post by jeremy »

Firstly I think your battery voltage is a bit low - Haynes quote 12.6 volts for a normal battery and describe 12.5 as poor. However as the voltage under load isn't dropping to 10's and the engine is starting its probably OK for the time being. (The significance of the drop to 10's is that this would mean that one cell had failed, rather than the whole thing just being a bit tired.)
I don't think your problem is glow plugs as if one or mor plugs had failed, once the engine started and revved the cylinders with the bad plugs would quickly fire up and work. There would be some unburnt fuel in the exhaust (white smoke) but the engine would run normally.
I think the reason the plugs glow once the engine runs is to reduce emissions and not really to aid running at startup. We have a ZX 1.9D and a BX TD (no after-glow) and the starting performance on both is near enough identical with perhaps advantage ZX which I had always put down to its youth (59 000 miles v 190 000 miles)
I think your problem lies with the injection system. Leakoff pipes are a well known source of problems and I suggest are replaced first. Otherwise it could be an injector problem. How old are they? Have you tried a cleaner recently? Does the car smoke? I know cleaned injectors made a world of diference to my BX, with immediate starting on 4 cylinders every time.
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AndersDK
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Post by AndersDK »

Crossman -
What I'm trying to say is :
The glow plug voltage should be tested AT the glowplug - not THRU any connections - otherwise you have NO indications of a possible dodgy connection - which is a common problem.
The end user of the high currents is the glow plugs - therefore the voltage should also be tested DIRECTLY on the glowplugs - not on any connections TO the plugs.
It's common electric measurement techniques that applies here - to avoid having any problems disturbing what you are actually looking for : namely the glowplug's factual working conditions.
The reason why I'm so keen on this - is that you allready replaced the plugs a year ago - & now the same problem appears again. Unlikely to be related to the plugs itself - as these in general are very reliable & durable.
Only other problem I can think of then - is an electrical connection/supply problem - or DaveBurns suggestion on incorrect plug types.
Crossman
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Post by Crossman »

Anders,
Sorry, perhaps I did'nt explain to well. I put the end of the multimeter on to each glow plug in turn as well, the feeder bar, the relay box; and each glow plug is getting a steady 11.7 volts of juice when glowing. I am off to take the rail off now so I will report back with the resistance of each glow plug as well as seeing what teh general state of the injecter pipes are (off comes the intercooler :-( ).
Thanks again for your help.
Crossman.
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AndersDK
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Post by AndersDK »

Right then [8D]
Keep us posted w/ any progress or new dull problems encountered [:)]
Crossman
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Post by Crossman »

Right,
It appears I have identified the problem, It's seems like I have one glow plug that has failed, and being sods law, it's the one nearest the timing belt behind the injection pump. Thankfully it should be fairly free as it was changed no longer than a year ago and it was put back with some coperslip type goo so hopefully it should come away without to much grief.
The resistance for the other glow plugs were about 0.8 ohms and this one was 1.8 Mega Ohms and sometimes the multimedia could'nt even register a resistance!
Looks like this I'll get it done this wednesday... [:(]
Crossman.
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Post by AndersDK »

Crossman -
Be VERY carefull winding/torquing down the new plug. As access to the plug under the roto-pump is allways a hassle (any model) - you tend to apply unduly forces to the plug while inserting it.
Crossman
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Post by Crossman »

Could possible be it, as you say it's a nightmare to get to. Obviously I put alot of effort into not snapping the thing on removal but on putting it in I can't remember much but for it to work through last winter a then give in seems a bit odd. I am suprised just how easy it is to star the engine (with 1 glow plug failed) when the engine is tempid, it only takes 3 or 4 cranks for it to catch...
Still I'm doing the job tomorrow so we shall see what condition the old one is in.
Crossman.
jeremy
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Post by jeremy »

I think what Anders is getting at is that you should screw the plug in with minimal force until it contacts its seat and then tighten it to the recommended torque (not very high)
I know on my TD BX no 4 plug (nearest the camshaft) was crossed and brought most of the thread out with it. Its not particularily difficult to get at but someone must have wound it in with a socket or something. I was fortunate and there was just enough thread and the head has since been replaced.
Jeremy
Crossman
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Post by Crossman »

I always put them in by hand, cant afford to take the whole engine to bits :(.
I'm having problems getting hold of Beru locally other than Citroen main dealer at £58 for 4 so I'm now waiting of andyspares delivering the goods for much less.
Crossman.
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