Citroen zx lumpy and hard to start 1.9 td

[dudarus1]

Hi i have a citroen zx 1.9 td and its developed a fault where when left overnight it becomes hard to start and then does finally start in a cloud of smoke. once started i drove it about 3 miles and it was well down on power then cut out and wouldnt restart untill i had primed the fuel again. Now i think that it must be drawing air in what do you guys think. is there a common failure on these making then let air into the fuel system,

thanks in advance
jake

[dudarus1]

just thought i would mention that at first i only noticed the problem in 3rd gear between 3000 and 4000 rpm

[spider]

If its doing it all time then its probably quite a bad ingress problem.

The starting issue could be just the fuel / air ingress or possibly a glowplug down, however I'm going to suggest that is not the case here as the glowplugs will have little if any effect really on a warm engine and certainly do not effect its running, once its running on four cylinders they do nothing at all.

Favourite ingress points are the fuel filter housing (the lid in the seal) if its a 'top hat' design of filter, ontop of the thermostat housing, black casing usually lid held on by four hex screws. The other favourite is around the primer bulb itself, either the actual bulb (yes really!) or hoses.

As the system is under negative pressure when running, ie the fuel pump is sucking the fuel up the pipe, its highly unlikely you would see any fuel leak. Overnight the air is being drawn into the pipe.

Things to do:

Do you have a clear plastic pipe on the fuel pump ? , some of these had the outlef from the filter to the pump in clear plastic, was very handy as you could see air bubbles.

What to do / initial test:

Before starting the car, open the bonnet. Operate the primer a few times until you feel a bit of resistance. Switch the ignition on but do not attempt to start it, return to the engine bay and operate the primer 3 or 4 more times.

Close the bonnet. Switch the ignition off, wait a few seconds then switch it on again, wait for the glowplug light to go out as normal and attempt to start it. Does it start any better ? Note if it still appears to 'misfire' or not and if it actually starts quicker or not.

[Xantidote]

Worth checking that the small rubbery fuel return pipes from the injectors are all OK, including the "cap" on the end injector

[dudarus1]

right thanks for replys think I've located the problem it's the fuel filter I've bypassed it and the problem is solved. there's a white thing on the side and the fuels coming from. is there supposed to be a cap covering this up I've took some pics links below

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thanks
Jake

[mirafioriman]

Is that the filter housing water drain? If so perhaps it just needs nipped up or there might be a seal on it that needs replaced.

[spider]

The white valve is the thermovalve. Basically it allows fuel (if cold) to go under the filter area to get heated by the metal in the thermostat housing as diesel fuel needs to be warm (avoids waxing in sub zero temps too) ideally for better efficiency.

The valve, if I remember its not available as a separate part. An o-ring has probably failed. You can try sealing it up "as is" if you wanted with a suitable sealant although be careful to find something that does not react to fuel.

Please don't run it permanently without a filter, the fuel pump *will* be damaged as there will be dirt and debris in the fuel. The pump is mighty sensitive to small particles of dirt.

As a 'quick' fix if you did not want to get another housing (the top hat design, that's fitted to most 93 to 97 1.9D units, they are more or less all the same so there's plenty of choice) would be an external filter of somekind.