I have a Xantia 1.9TD R reg, and when you switch the aircon on it miss fires. can someone help please.
thanks
Xantia TD Miss firing?
Moderator: RichardW
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Richard Gallagher
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I had this on my Xantia a couple of years ago after having the aircon regassed. The problem was caused by the so called aircon engineer putting too much gas into the system causing it over pressurise.
When this happens the compressor tries to overcome the high pressure causing the engine feel like its misfiring. The aircon system has a pressure regulator which then disengages the compressor allowing the engine to pick up again. All this happened within just a couple of seconds.
If this is the cause of your problem then the cooling fans will more than likely be running on their maximum speed which is rather noisy and therefore quite noticable, in order to reduce the pressure within the aircon system.
What I would recommend you to do is not to use the aircon without getting it checked over because if the system is over pressurising then it is likely to damage the system, bursting seals, damaging the compressor etc. Now that is VERY expensive.
When this happens the compressor tries to overcome the high pressure causing the engine feel like its misfiring. The aircon system has a pressure regulator which then disengages the compressor allowing the engine to pick up again. All this happened within just a couple of seconds.
If this is the cause of your problem then the cooling fans will more than likely be running on their maximum speed which is rather noisy and therefore quite noticable, in order to reduce the pressure within the aircon system.
What I would recommend you to do is not to use the aircon without getting it checked over because if the system is over pressurising then it is likely to damage the system, bursting seals, damaging the compressor etc. Now that is VERY expensive.
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philhoward
Could you more accurately describe the mis-fire please.
My Xantia (see below) has always had a moments 'hesitation' at somwhere in between 2000-2500 in 2nd/3rd gears (if I remember correctly) when the air-con is running. It has done this since new and still does it after an air-con re-gas.
I belive that at least one other person in this forum has reported the same problem.
Richard
My Xantia (see below) has always had a moments 'hesitation' at somwhere in between 2000-2500 in 2nd/3rd gears (if I remember correctly) when the air-con is running. It has done this since new and still does it after an air-con re-gas.
I belive that at least one other person in this forum has reported the same problem.
Richard
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philhoward
Had this problem, when I worked on lorrys, was explained to us by a scania guy who designed part of the layout, that its due to the extra weight of major engine (crank, flywheel etc) components in a diesel engine, the sudden pull of the compressor has a bigger effect than a petrol engine due to the kinetic energy of the crank etc.
The effect in a petrol engine is not as noticable due to less turning force of the coponents, If you think its bad in a xant, try it on an old diesel granada[:0] Feels like the cranks going to come through the wing.
The effect in a petrol engine is not as noticable due to less turning force of the coponents, If you think its bad in a xant, try it on an old diesel granada[:0] Feels like the cranks going to come through the wing.
Perhaps I had something similar on my TD BX. I had the alternator control unit fail and the thing would overcharge due to the voltage risisn. This was an intermittent fault as the headlights would get less dim and then go back to normal.
On a steady throttle a slight hesitation was quitenoticeable presumably as the alternator load varied, and this dissappeared when i fitted a reconditioned alternator.
Jeremy
On a steady throttle a slight hesitation was quitenoticeable presumably as the alternator load varied, and this dissappeared when i fitted a reconditioned alternator.
Jeremy
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philhoward
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Richard Gallagher
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Yes, the third injector is the one with what is called a 'Needle lift sensor'. Its purpose is to tell the ECU when the fuel is being injected and to compare that with the flywheel sensor to correct the fuel timing.
When my Xantia was new, I had the engine management light coming on when the engine was on the 'overun'. This injector was replaced together with the wiring/connectors running to the injector, now the light does not illuminate but the ECU does still record an intermittant fault. At all times however, the car has run absolutely fine, apart from the air con problem.
I would have thought that if this injector was causing the problems stated above, then the ECU light would illuminate now and again.
The best thing to do is to get a 'Code Reading' from the ECU. Do you live anywhere near Slough/Iver? If so I can do it for you, now theres an offer!
When my Xantia was new, I had the engine management light coming on when the engine was on the 'overun'. This injector was replaced together with the wiring/connectors running to the injector, now the light does not illuminate but the ECU does still record an intermittant fault. At all times however, the car has run absolutely fine, apart from the air con problem.
I would have thought that if this injector was causing the problems stated above, then the ECU light would illuminate now and again.
The best thing to do is to get a 'Code Reading' from the ECU. Do you live anywhere near Slough/Iver? If so I can do it for you, now theres an offer!
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Dave Burns
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- Location: United Kingdom
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- x 2
I doubt the jerk caused by the compressor cutting in is anything to do with extra rotating mass of a diesel, if anything, the more there is of it the less the jerk should be felt because there is more stored energy if the parts are heavier.
I think its because the diesel revs slower than a petrol, the compressor on the petrol probably has a larger pulley to gear it down because of the higher speed range of the engine, or petrols might have a smaller crank pulley.
A diesel compressor in comparrison probably has a smaller pulley to gear it up, or a larger crank pulley to achieve the same result.
But a diesel will pull away on tickover, a petrol will just stall if you try it, so with all that low down grunt and torque it can't be to do with power to my mind.
I had aircon problems a year or so back with my xantia, when the weather was at its hottest the compressor would cut in and out rapidly, causing terrible jerking just like a missfire, never found out why as it stopped doing this of its own accord, well it would wouldn't it, its a bloody citroen[:)]
You can check if the lift sensor is working by disconnecting the tdc sensor, if its ok the tacho will keep going, if not the tacho will stop and the increased diesel knock will put the sh!ts up you.
Dave
I think its because the diesel revs slower than a petrol, the compressor on the petrol probably has a larger pulley to gear it down because of the higher speed range of the engine, or petrols might have a smaller crank pulley.
A diesel compressor in comparrison probably has a smaller pulley to gear it up, or a larger crank pulley to achieve the same result.
But a diesel will pull away on tickover, a petrol will just stall if you try it, so with all that low down grunt and torque it can't be to do with power to my mind.
I had aircon problems a year or so back with my xantia, when the weather was at its hottest the compressor would cut in and out rapidly, causing terrible jerking just like a missfire, never found out why as it stopped doing this of its own accord, well it would wouldn't it, its a bloody citroen[:)]
You can check if the lift sensor is working by disconnecting the tdc sensor, if its ok the tacho will keep going, if not the tacho will stop and the increased diesel knock will put the sh!ts up you.
Dave
many years ago i had a volvo f12 truck with a 12 litre engine.ihad a problem with a completely flat battery where i couldn't stop the engine.i got underneath to investigate and found that the output wire of the alternator had snapped.with engine running i repaired and reconnected the wire.the load on that little alternator was enough to nearly stall 12 litres of engine and associated gearbox.