ZX TD Cold start

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Paul Thomas
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ZX TD Cold start

Post by Paul Thomas » 13 Aug 2002, 20:05

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My 1993 ZX Volcane TD 95,000 miles has gradually got more dificult to start over the last few weeks.
I fitted a new battery less than two years ago and new glow-plugs 12 months ago.
It turns over fine (slightly faster after a battery charge overnight!) but will not catch.
It has now got to the point that it won't start at all.
I have checked that there is fuel in the filter and that the tank isn't empty.
I can keep trying until the battery gives up with no joy.
There is also a 2 way plug in-line near to the bottom of the fuel filter where the outer cable have deteriorated, there is still a good connection but I will need to strip it apart and re-make it.
Any further ideas ? (I can't afford to take it to the garage)
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Post by RichardW » 13 Aug 2002, 20:33

Paul,
There are 3 reasons why a diesel won't start:
1. No heat from glowplugs
2. No diesel
3. Poor compression
To aid diagnosis of your problem, some more info is required:
When you could start it, was it also difficult to start when hot, and prone to erratic idle, sometimes leading to it stalling? This would point to an air leak in the diesel fuel supply. Try pumping the primer and then trying to start it.
What colour (if any) is the smoke coming from the exhaust pipe when you crank it? White / grey smoke indicates diesel is getting in but not combusting, points to a problem with preheating or compression.
When was the last time the cambelt was changed? Old cambelt could have jumped a tooth or two and thrown your valve / injection timing out which would make it difficult / impossible to start.
Was / is it using any water? Possible sign of headgasket problem - this usually doesn't prevent you starting it, but can make it lumpy / smoke right after start up.
Was the engine running on after switch off? Could indicate failed stop solenoid - check you are getting 12V to this with the ignition switched on.
Other checks: Check that glowplugs are seeing 12V for about 10s after switch on. Take off the glowpug feed wire and measure the resistance to earth through the plugs - it should be very low (about 0.25 ohm if all are working). You could get a compression test as well, which will reveal any problems with valve timing etc.
Connector to the fuel filter is probably only a water level switch.
Unfortunately there are a myriad of causes, and you just need to work through them one by one till you find the right one (been there done that....) Since you've had new glow plugs, my money would be on an air leak (although they usually start - eventually!).
Richard
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NiSk
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Post by NiSk » 13 Aug 2002, 20:35

Do a compression test to check out the compression. A diesel with poor cold compression will not start! (However you could probably tow start it).
If the compressions O.K., then it's either the glowplugs not lighting up or air in the fuel line.
You can check the glowplugs with a voltmeter to ground from the terminal on the top (or a check-lamp screwdriver for that matter).
Otherwise try replacing part of the fuel line (closest to the pump)with a piece of transparant plastic to check for air bubbles.
I'm sure one of these checks will turn up the culprit!
//NiSk
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Post by Paul Thomas » 13 Aug 2002, 20:49

A few more things to add:-
As I mentioned, it got worse over a few weeks/months although with the school holidays and a new vehicle it hasn't been used much over the last 4 weeks.
It first was difficult to start in the morning, I immediately suspected the battery as it didn't seem to turn over fast enough.
I jump started it a few times in the morning and drove to work (30-35 mins) ok. It would then start fine in the evening to come home and indeed the next morning as well.
If I left it for a couple of days I would have to jump start it to get it going again.
I have also tried charging the battery overnight and then starting it in the morning but this has so-far failed to work.
I will try jump-starting it again tonight (My new 3.9 v8 Discovery could jump start anything) and see if it works.
If it does I will assume the batteryis sha99ed and replace it accordingly.
The cambelt was changed at approx 85,000 miles.
Any more advice based on this ?
Edited by - Paul Thomas on 13 Aug 2002 15:50:56
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Post by vanny » 13 Aug 2002, 22:33

If jump starting helps, dont automatically assume the battery. I had the same problem when i first inherited my 1.9RD BX and even though Citroen had spent £2000 fixing the problem of the battery being dead if the car wasnt used at least once a week. It turns out there was some sort of wiring problem, but im not totally sure what solved it a mixture of the following.
First thing that helped was a new radio. Didnt do this deliberate, i only wanted speakers in the rear and the unit cost me £35. After changing this i only had to jump start once every month or so. Along with this is a new starter and a rebuild of the earth from battery to engine (good cleaning with degreaser and wire wool on all the metal parts, then an extra 30amp line between battery trminal and engine). Since then i have NEVER had to jump start the car because of a flat battery, ill admit the car gets used much more, but the other day i left the lights on (yes i know im stupid) for several hours and the car started first time without a problem. The likely hood is you have a similar drain in the system (such as a radio), but i dont think this would cause the engine to refuse to start.
Vanny
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Post by Dave Burns » 13 Aug 2002, 23:31

Split leakoff pipes between the injector's and also the blanking cap are common causes of difficult starting because air gets drawn in.
Give the priming bulb a good few squeeses before trying to start it, this often gets them going.
Also if its got an auto bleed valve between the filter and pump, these can go ape and let air in.
Dave
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Post by Paul Thomas » 14 Aug 2002, 13:38

UPDATE
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I jump started it from my Discovery last night and it started 2nd turn of the key and ran quite happliy.
I have previously checked the drain off the battery with my multimeter and it was less than 0.02 amps.
I checked the battery voltage while the engine was running and it was 14.28 volts which seemed a bit high to me, although if it thinks the battery is low it may compensate ? - any comments ?
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If it ain't broke ....... Leave it alone !
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alan s
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Post by alan s » 14 Aug 2002, 14:26

I have a CX C-matic that was just a bit cranky to start. Occasionally it would half start & then carry on as though it was going to & then within a few minutes just give up the ghost.
It seemed as though if you "caught it" first time you were right but if not it seemed to flatten the battery in no time. The battery was a fairly new 500cca which is much bigger than required (380 - 420 cca) and was checked out as being OK.
Eventually my patience wore out as it just used to play up when I was late going somewhere, making me even later, so acting on a hunch, I fitted another starter motor I had there that had been fitted with new brushes. It almost threw the motor out of the car it spins it so fast now. I know a CX isn't a diesel, but CXs are notoriously slow on the starter and this one almost sounds like a Mitsubishi (I'll go wash my mouth out) instead of a Paris Rhone.
It seems that the worn brushes were causing the starter to draw more power than it normally would and was thereby draining the battery as well as turning slower than it should. A case of a catch 22 situation. May be worth a thought.
Alan S
Edited by - alans on 14 Aug 2002 09:29:54
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Paul Thomas
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Post by Paul Thomas » 22 Aug 2002, 13:51

I can now pass on a bit more info:-
The battery has been tested by a local car shop for fizzing , charging and a drop test and has proven to be OK.
I have filled the fuel tank up as it was quite low and I know my ZX doesn't like the tank getting too low which can cause problems starting.
I jump started it on Tuesday and it has started OK each morning and evening since.
The only other thing I have noticed is that it doesn't fast-idle when started. After about 5 minutes of idling it then starts to fast-idle. Any ideas ?
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NiSk
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Post by NiSk » 22 Aug 2002, 14:09

Cold start mechanism on diesel pump??
//NiSk
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Paul Thomas
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Post by Paul Thomas » 22 Aug 2002, 14:50

What does/should the cold start mechanism on the diesel pump do ?
How do you test it ?
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Jon
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Post by Jon » 22 Aug 2002, 15:02

Cold start mechanism/cable is easy to find then check. One end screws into the side of the thermostat housing, down behind the filler neck, out of it comes a cable which attaches to the choke (cold start enrichment)on the back of the diesel pump.
It depends on coolant temperature to operate. When the coolant is cold, the cable should be tight, and the enrichment device is pulled on. When the coolant warms up, the waxstat melts, releasing the cable and turning the enrichment device off.
So, therefore, with the engine stone cold, say first thing in the morning, the cable should be taught, if it is slack, then the device is not working and should be replaced.
Paradoxically, with the engine/coolant hot, the cable should be slack, if it is still tight you're running around with the choke on.
Hope I have not waffled too much to explain this.
JW
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Dave Burns
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Post by Dave Burns » 22 Aug 2002, 15:51

The only times my ZXTD wouldn't start was because of air getting in via the leakoff pipes or the auto bleed valve as already mentioned.
Its either going to be fuel or preheat that stops it, both are easey to check when the symptoms arise, assuming the compression is ok.
Loosen the injector pipe union's on the pump one turn, use two spanner's, one to stop the delivery valve on the pump turning.
If it wont start and there are healthy pulses of fuel being ejected that more or less rules out the fueling.
KEEP HANDS CLEAR OF ANY SPRAY and be aware of the fire hazzard.
Get all the glow plus out, jubilee clip them together tightly in a bunch and to a good solid earth conductor, see if they ALL GLOW AT THE TIP and for what duration, its a ball ache I know but if you want to get to the bottom this mystery you can't take short cut's.
Don't be tempted to test them individually, everything must be tested at its normal working load.
If you have had any new plug's recently they may be of an incorrect type, they must be for the TD engine, n/a plug's can and do interfere with and damage the preheat relay on a TD besides not glowing properly, Iv'e seen it happen.
The cold start mechanism doesn't inject more fuel when the engine is cold, all it does is turn the cam ring inside the pump which advances the injection timing by about 5 degrees of the crankshaft.
Dave
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Jon
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Post by Jon » 22 Aug 2002, 16:04

Day off Dave?
I should have mentioned when I made my post about the cold start cable/waxstat that if its not working then it won't have any bearing on the engine starting, it just raises the RPM for the first 5 minutes or so.
Talking about air leaks, poor starting etc, I had a ZX TD Volcane once that refused to cold start, despite every test and tip known to man! It could take 2 minutes of cranking to get the thing going.
Replaced were the leak off pipes, the seal under the fuel filter housing, the rubber plunger bulb (bleed) in the fuel pipe, the glow plugs,the cold start cable; well the list kept going on. Then someone mentioned something about a vent to the fuel tank, we replaced that too. Then I gave in and took it to my mates Citroen garage. They could not find what the problem was either, but there was talk of a "sticky valve". The car rang perfectly, and started fine after the initial attempt.
In the end I solved the problem. I sold it <img src=icon_smile_big.gif border=0 align=middle>
Just thought I'd share that one.
Jon Wood
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Dave Burns
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Post by Dave Burns » 22 Aug 2002, 16:36

Hi Jon, yep l o n g weekend<img src=icon_smile.gif border=0 align=middle> know what you mean about the tank vent, mentioned something about it to another guy on here a week or two ago, doesn't seem to have helped him though, he's still got his prob's.
Dave
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