Poor acceleration response

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Russell
Posts: 102
Joined: 20 Jan 2004, 03:15
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Poor acceleration response

Post by Russell »

Hi,
On my new (to me) 1993 Citroen XM 2.1 TD auto, the accelerator is heavy and the engine is slow to respond. If I blip it at idle, (say a quickish half throttle stab) it goes BLEURGGHH, don't wake me up, etc.
[|)]
A Pug 405 1.9 turbo diesel I also have goes VROOM!! idle [:D] with the same test, so I think it should be something that can be adjusted.
How do I get some VROOM into my languid Citroen??
Cheers
Russell
Dave Burns
Posts: 1915
Joined: 14 May 2001, 05:30
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Post by Dave Burns »

What does it start like and what does it run like straight after cold starting, any missifirng and if so for how long, any smoke.
Whats the mileage.
What injection pump is fitted.
Have you renewed the fuel/air filters.
What operates the kick down, is it a cable.
Dave
Russell
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Joined: 20 Jan 2004, 03:15
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Post by Russell »

Hi Dave,
It runs very well, smooth and a bit too sedate.
Puff of smoke on startup, otherwise no smoke, even when putting the boot down. Slight tappetty ticking at idle, not expected, assumed hydraulic lifters would be quiet.
Injection pump I think is Bosch, hopefully, the good one.[8)]
Mileage is 160K, the air filter should have been renewed at the last service a month ago, need to check the history, but if not, I expect a year ago.
I thought the kickdown is operated by a potentiometer on the throttle but I haven't been close enough to the works to find out, there are two cables on the injection pump, I thought the other cable was a heating up enrichment device, but it could be kickdown I guess.
Ok, I don't know.[:(]
So, whaddya think should be the next move..?
Apart from change the timing belt [:)]
cheers
Russell
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uhn113x
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Post by uhn113x »

Russell
Does it kick down OK? If not, cable may be off - my BX did that when a clip came off carb, it also 'flared' going from 3 to 4
Mike
Dave Burns
Posts: 1915
Joined: 14 May 2001, 05:30
Location: United Kingdom
My Cars:
x 2

Post by Dave Burns »

Well I don't know if the kickdown is via cable or electric, but if cable may go some way to explaining the heavy throttle, then again if it has a Bosch pump does it still have the damper fitted, if yes do what most do and wang it.
You haven't got it in drive when you blip it have you, just a daft though[:I]
Is the tappety rattle really a tappet or diesel knock from too far advanced injection timing or a sticking injector, could explain power.
Basic engine timing could be a tooth or two out causing the power to drop, but the fact that you say it runs ok and there are no apparent starting problems and no smoke, would lead me to think it was slightly fuel starved for whatever reason, either clogged fuel filter, pump settings off or possible air ingress.
Dave
Russell
Posts: 102
Joined: 20 Jan 2004, 03:15
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Post by Russell »

Hi Dave,
I'm going to get the book out and look in the dark..
What's this Bosch damper business [?] as this sounds like a possible.
I'm pretty certain the tappety noise is really tappets or valve train something, it's not a pinking or tinging, just a single gentle patter like one tappet with a bit more clearance than the others.
Clogged fuel filter sounds good: wheres that hiding [?]
Air ingress theory, would be on the exhaust side ? or a known troublespot somewhere else maybe..?
Thanks for all the suggestions.
Cheers
Russell [:)]
Dave Burns
Posts: 1915
Joined: 14 May 2001, 05:30
Location: United Kingdom
My Cars:
x 2

Post by Dave Burns »

Damper looks like a small shock absorber on the front of the pump, between the accelerator lever and a bracket fixed to the pump.
Fuel filter is in a plastic housing on top of the thermostat housing.
By air getting in I meant in to the fuel, but there would be missfiring to accompany it, so if there's none of that it can be discounted.
Dave
Russell
Posts: 102
Joined: 20 Jan 2004, 03:15
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Post by Russell »

Ok I've just tried to identify my fuel injection system.
I reckon it's definitely early mechanical Bosch, VE532 or VE531 according to Haynes, the accelerator cable pulls on lever with two slots in. Another cable hangs onto the throttle lever, winds round a pulley, and goes off to sort out something (cold enrichment?).
A cam/switch is operated by the cable on this pulley when the accelerator is pushed about 2/3rds down, this switch clicks and might be the kickdown control.
Blowed if I can see a damper, but I'll check again in the morning when it's light. Resistance to moving the accelerator floorwards is a coiled vertical spring around the throttle lever shaft that winds up with cable movement, looks to have 4 turns on it.
Cheers
Russell [|)]
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