2.1 HUNTING

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xf8u
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2.1 HUNTING

Post by xf8u »

I have a 1997 2.1 Xantia with which I am more than pleased.
One little problem soon after cold start is that the engine starts hunting at about 1500-2000 rpm for about 5/6 seconds. I have to push the clutch in and wait while it goes back to normal.
I'm thinking it's an ECU issue due to drive by wire. I am reluctant to disconnect the battery and reset everything because I dont have code for radio.
Could it be a sensor somewhere that needs cleaning/replacing.
Thanks
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Post by CitroJim »

I would think this is caused by a small air leak on the fuel delivery side causing air to be sucked into the pump on start-up. It is very similar to what occurs on a Bosch-equipped 1.9TD when the leakoff pipes are just beginning to fail.

The leakoff pipes won't be your problem because you have a Lucas Epic and they don't suffer in the same way.

If you have a clear section of pipe between the filter and pump, observe it after a start and see if you can see any large air bubbles in there that clear after a few seconds. If so, check backwards from the pump to the fuel filter and primer bulb for air leaks. They will not be obvious because they don't leak fuel.

If you do have air getting in, it is bad news on a Lucas Pump. They can "run away" if too much air gets in and upsets the action of the hydraulic servos.

Is the engine otherwise easy to start?
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Post by xf8u »

Thanks for info Jim. I will inspect the necessary areas of concern. I will say that I have noticed bubbles in the clear section of pipe.
I have also noticed that there is a bleed nipple on there too.
What is the procedure for bleeding the fuel?
Can these clear pipes be replaced with suitable rubber ones?

The car is otherwise great. It starts fine and drives well.
Thanks
Mike
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Post by jeremy »

The clear pipe to the injection pump has been fitted by someone trying to find air leaks! Its commonly done when air leaks are suspected - after some time the pipe will probably harden and I think B&Q will supply something similar.

The fuel circulates and a large proportion is returned to the tank in normal running. This ensures that air is got out of the system - but too much air will overwhelm it. Generally you bleed a diesel sufficiently to start it.

Older engines have separate mechanical lift pumps and its necessary to bleed the low pressure circuit before the engine will run. This means that running out of fuel is a rather involved process and more modern engines have the lift pump incorporated in the injection pump and can simply be primed by a small pump - in your case a bulb-type pump somewhere in the piping before the filter.

Sounds like you have a leak somewhere before the pump - check all joints - plus the priming buld (perishes) and the fuel heater thermostat which in in the filter housing (on a ZX which has the filter in the middle of the engine space above No 1 injector its low down at the back on the left of the filter housing)
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Post by CitroJim »

jeremy wrote:The clear pipe to the injection pump has been fitted by someone trying to find air leaks!
I've seen so many later TDs with a run of clear pipe I always believed it was put there when the car was built :?

The filter housing itself can be a source of leaks through cracks. Fairly recently I found a leak caused by one of those counterfeit fuel filters I got hold of. It had swelled badly and was pushing up the lid of the filter housing.

The big problem is finding the leaks as they draw air but don't, as a rule, leak diesel. Substitution is the only sure way, starting with the simple, cheap bits :wink:
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Post by Xaccers »

I've had the odd airbubble or two go along the clear pipes on my 2.1TD too.
Think I narrowed it down to the pipe between the bulb and the fuel filter, it looks like it's cracking (actually looks like some blue chewing gum has been used to fix it before) so I'll be replacing it asap.
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Post by deian »

I think all 2.1td's had clear pipes from the factory, they can't all have been changed by a previous owner can they?
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Post by JohnD »

deian wrote:I think all 2.1td's had clear pipes from the factory,?
They did!!!!!!! My last car was a 2.1 Xantia which I had from new.
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Post by Xaccers »

Clear from the bulb to the filter, and from the filter to the pump.
I'm guessing so you can see if you've bled the air out properly from the pump's nipple, seeing as these pumps really don't like air in the fuel.
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Post by Peter.N. »

The 2.1 td in the XM has a fuel heater bolted to the gearbox end of the cylinder head, these are prone to going pourous and letting air in.
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Post by Xaccers »

Peter.N. wrote:The 2.1 td in the XM has a fuel heater bolted to the gearbox end of the cylinder head, these are prone to going pourous and letting air in.
As in cracks appearing or a seal going?
Does the whole unit need to be replaced?
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Post by weety »

JohnD wrote:
deian wrote:I think all 2.1td's had clear pipes from the factory,?
They did!!!!!!! My last car was a 2.1 Xantia which I had from new.
wow now that is citroen....put something in as standard that will probably only be of use to people a decade later.....thats why i love them :D
M reg xantia 1.9td 266000 miles expired
R reg xantia 1.9td 186000 miles veggy power expired
L reg renault clio 1.9D 91000 miles expired at 107000 miles
x reg clio 15d veggy power bottom of the car rotted through
06 c5 2.2 TD wowser so much power and comfort 160000 miles
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Post by weety »

xf8u wrote:Thanks for info Jim. I will inspect the necessary areas of concern. I will say that I have noticed bubbles in the clear section of pipe.
I have also noticed that there is a bleed nipple on there too.
What is the procedure for bleeding the fuel?
Can these clear pipes be replaced with suitable rubber ones?

The car is otherwise great. It starts fine and drives well.
Thanks
Mike
dont know if its of use but you can get the clear pipe on flea bay

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... &rd=1&rd=1

and the primers

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... &rd=1&rd=1

and my local car spares sells 10 metres of fuel hose for £17 (pearl parts) so you should be able to get a similar deal
M reg xantia 1.9td 266000 miles expired
R reg xantia 1.9td 186000 miles veggy power expired
L reg renault clio 1.9D 91000 miles expired at 107000 miles
x reg clio 15d veggy power bottom of the car rotted through
06 c5 2.2 TD wowser so much power and comfort 160000 miles
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Post by Peter.N. »

Xac wrote:
Peter.N. wrote:The 2.1 td in the XM has a fuel heater bolted to the gearbox end of the cylinder head, these are prone to going pourous and letting air in.
As in cracks appearing or a seal going?
Does the whole unit need to be replaced?
No, the usual remedy is to disconnect the pipes and join the ends together. Diesel heaters are not normally needed inthis country now
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Post by davethewheel »

my 2.1td also has bubbles that i can see in the clear section of pipe they seem to be made worse if i squeeze the bulb, i've had a problem since i got the car, it's as though you still have you foot on the accelerator as when you dip the clutch the engine revs rise, i always thought that it must be a problem with the ecu or the pump maybe it's related to air in the fuel.
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