Citroen C5 HDI Lack of Power and Banging
Moderator: RichardW
Hi,
Could well be a leaking or disconnected vacuum pipe or sticking turbo variable vane mechanism.
The turbo variable vane control is actuated and adjusted by vacuum.
This adjusts the vanes to ensure high velocity exhaust gas onto the turbo wheel at low revs/low exhaust flow and opens them up as engine revs rise and exhaust flow increases to control the gas velocity onto the turbo and thus control turbo speed and prevent over boost.
If the vanes stick closed up you get the over boost fault. If there is no vacuum or they stick open you get much less boost (and therefore less power or torque) until the revs reach about 3000.
There is a capsule on the top with an approx 1/4 in rubber vacuum pipe to it.
The C5 runs almost as much on vacuum as on electronics !!
John
Could well be a leaking or disconnected vacuum pipe or sticking turbo variable vane mechanism.
The turbo variable vane control is actuated and adjusted by vacuum.
This adjusts the vanes to ensure high velocity exhaust gas onto the turbo wheel at low revs/low exhaust flow and opens them up as engine revs rise and exhaust flow increases to control the gas velocity onto the turbo and thus control turbo speed and prevent over boost.
If the vanes stick closed up you get the over boost fault. If there is no vacuum or they stick open you get much less boost (and therefore less power or torque) until the revs reach about 3000.
There is a capsule on the top with an approx 1/4 in rubber vacuum pipe to it.
The C5 runs almost as much on vacuum as on electronics !!
John
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Okay so what to do?
Okay given all of this what would you recommend?
Should I visit the local Bosch to get the computer read (will any turbo problem show up in an error?) or should I just blindly put it into the local (Dundee/Montrose) Citroen Garage and let them blindly find it and sort it out.
My concern is cost. I am skint.
Should I visit the local Bosch to get the computer read (will any turbo problem show up in an error?) or should I just blindly put it into the local (Dundee/Montrose) Citroen Garage and let them blindly find it and sort it out.
My concern is cost. I am skint.
Hi,
As far as vacuum leak is concerned you could get a vac gauge (about £20) and some plastic pipe and connectors (B&Q) and try to check out where you do and do not have adequate vacuum.
Ideally you should have about 800mbar any thing less than 300-200 will give problems.
You need to disconnect pipes, connect in the gauge and see what you have. Time consuming but cheap and probably easy to fix if you find a leak/faulty item.
There is another there topic currently active on the forum regarding swirl valve actuation that gives some good general advice about vac leaks and fault finding.
Regards
John
As far as vacuum leak is concerned you could get a vac gauge (about £20) and some plastic pipe and connectors (B&Q) and try to check out where you do and do not have adequate vacuum.
Ideally you should have about 800mbar any thing less than 300-200 will give problems.
You need to disconnect pipes, connect in the gauge and see what you have. Time consuming but cheap and probably easy to fix if you find a leak/faulty item.
There is another there topic currently active on the forum regarding swirl valve actuation that gives some good general advice about vac leaks and fault finding.
Regards
John
Hi,
Apologies, believe you are correct it will be a fixed vane with wastegate.
However, the symptoms are exactly the same as those my wife's C3 1.4HDi 16v (which has a VV turbo) suffered recently and the cause was a leaking vac pipe on the variable vane control system.
A similar logic may apply, that is if the waste gate is stuck open you won't get any boost until about 3000rpm.
However, not sure how a waste gate turbo is controlled these electronic days.
From looking at the exploded diagram on citroen service site there seems to be mechanical link controlled by a diaphragm capsule which has a pipe back onto the turbo body. So presumably it is operated as of old, directly by excess boost pressure.
regards
John
Apologies, believe you are correct it will be a fixed vane with wastegate.
However, the symptoms are exactly the same as those my wife's C3 1.4HDi 16v (which has a VV turbo) suffered recently and the cause was a leaking vac pipe on the variable vane control system.
A similar logic may apply, that is if the waste gate is stuck open you won't get any boost until about 3000rpm.
However, not sure how a waste gate turbo is controlled these electronic days.
From looking at the exploded diagram on citroen service site there seems to be mechanical link controlled by a diaphragm capsule which has a pipe back onto the turbo body. So presumably it is operated as of old, directly by excess boost pressure.
regards
John
Assuming the setup is like that on my HDi 110 the wastegate is operated by vacuum via an electrovalve, so you could be right about it being a vacuum leak.
However, I may be wrong, but I think the wastegate on these is normally closed and opens when vacuum is present, so a vac leak would tend to lead to too much boost rather than too little.
However, I may be wrong, but I think the wastegate on these is normally closed and opens when vacuum is present, so a vac leak would tend to lead to too much boost rather than too little.
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Okay
Okay then, but I have no idea what these things are, so a trip to the dealer looks likely.
I am not a car nut really.
Does this show up in an error code or would this require the dealer mucking about until he doesn't find it.
I thank you guys form your help. I'll have to decide what to do. I assume local garages (non dealerships) can handle Citroens? (Dundee area)
I am not a car nut really.
Does this show up in an error code or would this require the dealer mucking about until he doesn't find it.
I thank you guys form your help. I'll have to decide what to do. I assume local garages (non dealerships) can handle Citroens? (Dundee area)
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Re: Okay
Maybe; Maybe not! You really need to go somewhere that has a good analyser a Lexia for preference and someone that really knows how to use it. Your local Citroen garage will have the former it's the later which is always in doubt . If you go to an independent it's a question you need to ask before agreeing to give them the car.boristhespie wrote:Okay then, but I have no idea what these things are, so a trip to the dealer looks likely.
I am not a car nut really.
Does this show up in an error code or would this require the dealer mucking about until he doesn't find it.
I thank you guys form your help. I'll have to decide what to do. I assume local garages (non dealerships) can handle Citroens? (Dundee area)
Cachaciero
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New noise
Incidentally the car is now making a noise from the belt thingie on the front lefthand side of the engine, with what looks like a leather band on it pushing the wheel underneath. See, I told you Iwasn't technical. Should I be worried?
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And....
The result being?
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IT is a French car, the workers that assembled it come from a common background, the designers doubtless come from the same universities, as do the cost control engineers, bean counters. Go figureboristhespie wrote:IF that were to break is it a knackered engine. Had the timing belt go on my laguna £1500 and then trubo £1500. Sold that for this. This wont happen here will it?
Cachaciero