xmv6si help please??

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Paulxmski
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xmv6si help please??

Post by Paulxmski »

When the engine of my 1990 XM V6 Si is started from cold it will not rev beyond 1500 - 2000 rpm . If you try to drive the car it will not go faster than about ten miles an hour on the flat and sort of chugs as the engine revs rise and fall. Once the car is warmed up and after a period of being stopped and switched off it goes fine until at some apparently random point in the journey it suddenly cuts out and then picks up again at around 40 mph. Sometimes it goes back to chugging mode??
Re first email:
Found it - the major loss of oil was caused by a blown oil pressure relief valve.
arry_b
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Post by arry_b »

Plug leads are the major suspect in my mind. Try starting it with the bonnet open in pitch darkness and watch for the light show!
Paulxmski
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Post by Paulxmski »

Hi arry_b,
Thanks very much for the reply. I will try the light test you have suggested. I think it is likely that it is something to do with the ignition system, because there is a Trafficmaster system installed, and the connections have been taken straight off the battery and are routed via a connetcing box which has been nylon tied to the block which carries the ignition module. The connections are via covered jacks and spades but it it all looks very ertzatz to me and was like this when I bought it. When I looked at the trafficmaster module it was dead and I noticed that the spiralling cable around the central cable had been cut - so no wonder, but in the guide I also notice that the ecu takes battery information into account. I think it is best to strip this thing out completely and start from there after doing the light test of course. I will have to find somewhere dark however since we are well lit up here in Bletchley - MK.
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Post by Paulxmski »

No I am sorry to say there is no light show going on under the bonnet. Any more ideas please??
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AndersDK
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Post by AndersDK »

Paul -
It's cruicial you try trace down the symptom being caused by either of 2 :
1) ignition
2) fuelling
With engine running - and problem present - try the following :
Remove each sparkplug cap 1 by 1 - observing a sturdy spark to earth of at least 10-12mm in free air can be obtained. It MUST be a sturdy & steady 10-12mm spark - loudly ticking.
At the same time observe if any plugcap removed is indifferent to engine running - clearly pointing to a problem with that cylinder.
Same method is used on the injector connectors - except you simply observe if any particular connector removed seems indifferent to engine running.
Any history on the sparkplugs ?
- they don't last forever - and both time & mileage is an aging factor [8)]
Any history on fuel filter ?
- it can't hold back powder-like dirt 100% - which is known to foul injectors & associated piping/parts over long service life.
NiSk
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Post by NiSk »

A lot of the faults reported on the Swedish Citroën-help website for XM V6's are due to:
1) Fuel filter
2) Battery
could be worth checking.
//NiSK
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Post by Paulxmski »

Hi guys,
Thanks very much for all the suggestions - Found it it was the battery although it is a new battery and has those beautiful bits of blue plastic shielding the terminals that are locked down by the handle which is in turn locked down by the cradle mountings. When dismantled to my horror (mock) the positive terminal was fully tightened in fact way over tightened so that the square side could spin in the lead, but the terminal was still loose when pushed. So I took the terminals off wacked on a good gob ofcopperease put copper shim in the positive terminal tightened up - bingo all sytems go with no hesitation and really a general transformation! I have another XMV6 which is currently not starting (mainly due to lack of use and it ran out of fuel. I think your suggestions will be useful for that too. Is there any procedure for priming the injectors. I noticed in the user instructions it warns against allowing them to run out or is that just because it might be slurping the crud at the bottom of the tank?
Thanks again everybody
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Post by Paulxmski »

Oh Oh it's not the battery. Seems Iwas a little hasty in thinking the fault was cured! Still doing the same thing. It definitely seems to be something switching and allowing the injectors to work properly when the car has warmed up, and it is significant that it must be really warmed up (i.e half a notch on the gage below N) because until it is then it just switches back into chugging mode again.
Once it is warm/hot and has been switched off and then on again it goes absolutely fine and like a rocket. There are none of the symptoms that go with fuel starvation (blocked filter), bad plugs (misfiring, bad pulling).
Does anyone know about the idle speed control valve? where it lives in the XM ? or how about the air temperature sensor or coolant sensor?
According to Zeljko's Citroen guide there is/may be an injector de-acceleration cut-out which can operate at 1500 rpm sounds like this may be operating in reverse? My old XM has none of these problems and I wonder if it is worth swapping the ECU and these other components is this a straight forward job?
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Post by rg »

Paul,
It may be worth posting on:
http://groups.yahoo.com/group/XM-L
Lots of XM knowledge available on there.
HTH
rg
Paulxmski
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Post by Paulxmski »

thanks rg I'll try that
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