XM 2.1 TD misfire under load and heater problems

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xm nut
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XM 2.1 TD misfire under load and heater problems

Post by xm nut »

Anyone any thoughts on a fix for a slight mis-fire at low revs (14-1800rpm) when engine is under moderate load. Problem disappears at other engine speeds and when turbo starts to work. Car runs fine otherwise and has had new injectors, head gasket, fuel and air filters in last year. Car has done 150,000 miles. Checked for fuel/air leaks but can't find anything. Could the diesel pump timing be out because of wear?
Also heater blower cuts out sometimes and will not function again at any speed unless the ignition switch is turned off and on again. Car has climate control so I suspect it is part of the control system. Heat still gets into car by force of passing breeze so the heating part of the system works. Also the fact that the blower comes on again with the ignition switch would suggest that the blower is ok. Is there some fault in the control system? How does it work?
Doc
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Post by Doc »

Hello XM Nut. I also own a 2.1 XM TD SED which has been difficult to start and will not rev beyond 3000 rpm. I have been advised that my turbo wastegate valve may be sticking. Sometimes they can be freed off by hand.
What state is your cambelt. If it is old and has stretched it may have shifted a tooth and therefore the timing even though this engine has an automatic tensioner. If the belt is okay check all fuel pipes and unions to and from the tank for leaks. Make sure the filter mount and bleed pump/plunger isn't allowing air into the fuel circuit.(Pump it several times. It should feel resistance. If not the rubber diaphragm may be perished).
As for blower system, check to see if any of the control relays have either worked loose, suffered corroded terminals or got wet. Check carefully all earthing points even those that don't appear to be related.
xm nut
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Post by xm nut »

Hello Doc Thanks for help.
Good idea about the wastegate sticking I'll get under the car to check
it. Cambelt has done around 20,000 miles and should be ok.
My car goes like a rocket when the turbo is working so there can't be much wrong with the cam timing. Also the wastegate seems to work at the top of the rev range. Maybe its sticking open a wee bit at low revs?
I have checked the fuel lines using bits of clear pipe and the line before the hand pump was fine. The line after was showing bursts of air from time to time so I fitted a pump/filter off a cx. This didn't help the slight misfire before the turbo chimes in, but the car now starts instantly! It always used to stagger into life before.
The earthing points are all clean and the later bolted type.
The problem I have with my xm is finding what relay does what. Do you know where the relays connected with turbo are?
Also do you know where the ones connected with the climate control are?
I read somewhere else here of a similar problem to yours caused by a split in the hose from the intercooler to the diesel pump over-fuelling device which senses the turbo boost pressure and supplies extra fuel - have you checked this pipe?
Doc
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Post by Doc »

Hello XM Nut.
I checked the pipe from the pump to the intercooler and guess what- it had two holes where the pipe had been rubbing against the rad. In the absence of a suitable replacement I have sealed them with radiator hose repair tape. I will test drive it this afternoon (18th Jan) and see what happens.
Yesterday I got under the car to check the wastegate and I hope the turbo never has to come out as it's buried deep. Tried to reach wastegate actuator rod but I couldn't fit any form of plier/molegrip between engine and basically everything else up there. Came to the conclusion that even though I like the shape of the XM, that low bonnet line sure does nothing for engine access!
On the subject of a misfire check your COOLANT TEMPERATURE SENSOR as this contains a thermistor which sends a signal to the Exhaust Gas Recirculator. On petrol engine cars, a malfunctioning EGR valve causes running problems. I am not sure if a diesel can be affected in the same way but it might be worth a look.
The aircon is controlled by an ECU plus engine management ECU and takes a feed from the cooling fan switch. On your display, if there is a fault with the aircon, the decimal point on the temp set control display will FLASH indicating the system is running with reduced efficiency. I think the relays are located within the box housing the main ECU.
As a point of interest my aerial was allowing water to run through the bolt hole and onto the back of the centre sun visor where it then dripped onto the centre console switches and dashboard electrics via the windscreen A-pillar trim. It wasn't a bad leak but it had been allowing water in over time. I had to remove aerial mount and waterproof the assembly with silicone RTV.
Doc
barwood
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Post by barwood »

Regarding the heating i've just had a problem with my climate control it turned out to be the air flap motor,to check it take out the glovebox (four screws and lift it out,careful of the wiring to the glovebox light) The motor is on the right as you look in the hole,if you operate the climate control up and down you should see the lever move. If it does not work you can take it off the air re-circulator valve on top of the blower motor (look over to the left of the hole and there it is,2 screws and its off
Doc
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Post by Doc »

Hello Barwood and XM Nut,
I have just spent all day looking for air leaks into the fuel lines. I made sure the filter priming pump was airtight (which it was) and remade a pipe connection that has some sort of flow triggering device fitted to it that may be linked to the alarm/immobiliser. The engine now runs and idles at 900 then drops to around 700 before resuming at around 900rpm. I didn't risk test-driving it as I don't like the idea of pushing a ton and a half of car off the road when it stalls! I suspect the leak may be somewhere between the tank and the filter. Car is booked into specialist so it can have a good exploratory. As car isn't smoking any more than a normal diesel the pump should be okay (should outlive the engine anyway)
I have owned diesels before, a Vauxhall Nova TD, Ford Escort Van and a Peugeot 309 but I have never experienced these symptoms before. I guess Citroen diesels are more susceptible than other makes.
I will yet you all know what it turns out to be.
Doc
xm nut
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Post by xm nut »

Hello Barwood
Your right the flap motor seems to stop working when I'm on the move and will operate when the ignition is switched off and on again.If the engine is switched off without the ignition being off, I can't hear the stepper motor working when the climate control knob is moved. If the ignition is switched off and on again I can hear it moving as the knob is turned.
I'll take it to bits and see if I can fix it. Thanks
Hello Doc
My car doesn't have an EGR system thank goodness. I can't get near the turbo wastegate to see if its at all sticky. I'm still convinced that the pump timing is out a little bit but don't know enough about diesels!
The car blows a fair bit of white smoke out the exhaust when powering up hills or exiting roundabouts just as (or before) the turbo chimes in.(Its quite impressive in the dark) Otherwise its quite clean and runs fine apart from the slight misfire at the same revs.
Your problem with revs rising and falling does sound like an air leak.
I've come across a similar sounding problem which turned out to be a hairline crack in the filter assembly in the fuel tank. This problem would disappear with a full tank though. He fixed it with araldite.
Check everything else first!
Doc
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Post by Doc »

Hello XM nut. I am going to inspect tank as you may be right about a crack in the tank/pipe assembly. As my fuel level is low and the car is parked on a slope I reckon air is getting in through here.
Took the air intake off to find it sooted up from the EGR valve. How can manufacturers think this helps emmissions? All it does is slightly lower combustion temperatures to reduce oxides of nitrogen. As diesels are smoke tested anyway, I am going to disconect the pipe and the valve sensor. The same thing can be done to Vauxhalls with the ECOTEC engines. On those engines, there is an auxilliary airpump and valve that cause all sorts of running problems when it goes wrong, which is most of the time. Ironically when disconnected the car produced lower emissions and always passed its MOT CO/HCO test.
Doc
xm nut
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Post by xm nut »

Hi
Just back from the pub.
Spoke to friend who had problem with the crack in the plastic housing of the filter assembly in his diesel fuel tank. He had to scrub the housing and examine it under a strong light before he found it. The fix with araldite worked superbly and his xm now runs as sweet as a nut - 220,000miles!
Examine carefully- best of luck!
AV
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Post by AV »

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
Anyone any thoughts on a fix for a slight mis-fire at low revs (14-1800rpm) when engine is under moderate load. Problem disappears at other engine speeds and when turbo starts to work. Car runs fine otherwise and has had new injectors, head gasket, fuel and air filters in last year. Car has done 150,000 miles. Checked for fuel/air leaks but can't find anything. Could the diesel pump timing be out because of wear?
Also heater blower cuts out sometimes and will not function again at any speed unless the ignition switch is turned off and on again. Car has climate control so I suspect it is part of the control system. Heat still gets into car by force of passing breeze so the heating part of the system works. Also the fact that the blower comes on again with the ignition switch would suggest that the blower is ok. Is there some fault in the control system? How does it work?


<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
AV
Posts: 11
Joined: 23 Jan 2003, 23:56
Location:
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Post by AV »

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
Anyone any thoughts on a fix for a slight mis-fire at low revs (14-1800rpm) when engine is under moderate load. Problem disappears at other engine speeds and when turbo starts to work. Car runs fine otherwise and has had new injectors, head gasket, fuel and air filters in last year. Car has done 150,000 miles. Checked for fuel/air leaks but can't find anything. Could the diesel pump timing be out because of wear?
Also heater blower cuts out sometimes and will not function again at any speed unless the ignition switch is turned off and on again. Car has climate control so I suspect it is part of the control system. Heat still gets into car by force of passing breeze so the heating part of the system works. Also the fact that the blower comes on again with the ignition switch would suggest that the blower is ok. Is there some fault in the control system? How does it work?


<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
AV
Posts: 11
Joined: 23 Jan 2003, 23:56
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Post by AV »

[I had a heater fan problem with a Xantia 1.9 td, which started of with the same symptoms you are having, when playing with the ignition failed I resorted to tapping the casing with a hammer which worked for a while. when it worked no more , I decided to change the motor brushes, I used some suitable ones from a friendly starter/alternator repairman, for the price of a pint, trimmed and filed them to fit, soldered them in place and the fan has worked, including the climate control (although my aircon is U/S but that's another story)ever since, give it a try.
Doc
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Joined: 30 Dec 2002, 04:11
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Post by Doc »

Hello XMNut.
I solved my running problems on my XM 2.1 and it turned out to be a faulty filter housing/primer pump unit. This was priming the filter as it should and going hard after pressing the plunger, yet was still sucking in huge amounts of air. What was annoying though was that the housing is only a few years old! It may have been a cheap pattern part or a porous casting. It was replaced with a Bosch unit and now the car goes like the proverbial rocket. I also had the glowplugs changed.
As I also had a misfire are you 100% sure you are not getting air into the fuel lines?
I can't imagine your diesel pump wearing out as they are designed to outlive the engine as excess fuel lubricates the moving parts. Unless the pump has been removed then timing should be as before.
Are you getting any knocking from injectors?
It could it be a sticking or lazy hydraulic tappet that isn't opening a valve completely at low revs but is okay at higher rev range when the oil pressure increases. My engine does this and I am debating as to use and engine flush before changing to a full synthetic diesel oil.
Doc
Doc
Posts: 150
Joined: 30 Dec 2002, 04:11
Location: United Kingdom
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Post by Doc »

Hello XMNut.
I solved my running problems on my XM 2.1 and it turned out to be a faulty filter housing/primer pump unit. This was priming the filter as it should and going hard after pressing the plunger, yet was still sucking in huge amounts of air. What was annoying though was that the housing is only a few years old! It may have been a cheap pattern part or a porous casting. It was replaced with a Bosch unit and now the car goes like the proverbial rocket. I also had the glowplugs changed.
As I also had a misfire are you 100% sure you are not getting air into the fuel lines?
I can't imagine your diesel pump wearing out as they are designed to outlive the engine as excess fuel lubricates the moving parts. Unless the pump has been removed then timing should be as before.
Are you getting any knocking from injectors?
It could it be a sticking or lazy hydraulic tappet that isn't opening a valve completely at low revs but is okay at higher rev range when the oil pressure increases. My engine does this and I am debating to use engine flush before changing to a full synthetic diesel oil.
Doc
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