xantia td lack of power and smoking

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spanner 1
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Joined: 07 Nov 2003, 03:47
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xantia td lack of power and smoking

Post by spanner 1 »

Got a problem with two xantia turbo diesels 1.9 heavy black smoke when revving and no guts in engine, in fact the one is auto and not enough power to pull of drive. both cars are the later style engines that are controled by ecu's . the one would be ok for a while, turbo cutting in nicely and no smoke but when it has rested for short time and restarted then she smokes and no power. have removed catalitic convertor, check filters and fuel quality, ecu checked no faults, one has had new turbo and is low mileage. ? fault in advancement valve in bottom of pump now that choke stat has been done away with.[?][?][?]
Richard Gallagher
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Post by Richard Gallagher »

I had a similar problem with a previous Xantia TD which lost power and smoked the longer the engine ran. In the recent hot spell it became totally gutless in the extreme. I went through absolutely everything, even checking the pump timing, swopping injectors etc etc.
I eventually traced it to believe it or not, the air filter inlet hose which had rotted away, causing the engine to take in hot air from the radiator rather than cool air from outside the engine bay, thereby significantly reducing the efficiency of the intercooler.
The relevant hose sits below the air filter housing.
Yes I was pleased to trace the fault but I must admit to being a bit peeved at missing out the easy cheap solution first.
Well worth a quick look.
Dave Burns
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x 2

Post by Dave Burns »

Yes could be that but if it is I you should notice a significant change in the diesel knock, getting louder if the valve loses voltage altogether and goes to full advance, or quieter if it goes to retard in a big way, what signal it would need to do that I don't know.
Could be either the injector lift sensor or the TDC sensor at fault, this will prevent the ECU from working out the correct timing advance value for the valve, a quick check for a totaly bad sensor is, when the fault occurs, disconnect the TDC sensor (engine still running in fault state) on top of the bell housing, check the tacho, if its still reading ok re-connect the TDC sensor and disconnect the injector lift sensor, if the tacho still reads engine speed ok then both sensors would appear to be functioning normaly, disconnecting either of these sensors when they are working properly should produce a slight change in the engine sound during tickover.
The tacho will work as long as one of the sensors is connected, therefore if it stops reading when one of the sensors is disconnected, that must mean the other still connected sensor or its circuit is at fault.
If this seems to check out, pull the advance valve plug (brown) and listen for a change of noise, if it knocks loudly then the valve appears to be working ok, if the engine is allready noisier than normal and pulling the plug makes no difference then the valve is either allready in a no signal state or wrong signal state.
Dave
p.s choke stat done away with, engine idle speed when cold now done by ECU and vacuum electrovalve.
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