Xantia poor running

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
JohnS
Posts: 4
Joined: 08 Aug 2004, 22:17
Location:
My Cars:

Xantia poor running

Post by JohnS »

I have a tricky problem with a 1998 1.9 TD. There is severe power loss - foul on hills, towing the caravan, acceleration and top speed. 0 - 60 is 18 secs and top speed, just, 85 mph. The turbo is whining OK. Now the odd thing is that I have had a problem with the intermittent working of the rev counter since I've had the car.
When the rev counter IS working the the power is awful, as described. But when the rev counter is NOT working the engine runs rough, clattery and smoky but performs a whole lot better, accelerating as I would expect!
Local dealer cannot solve it, suggesting the the cat had broken up and blocked the exhaust which I've replaced with no improvement and a hole in my wallet. Any help gratefully received
nick
Posts: 1079
Joined: 14 Mar 2001, 01:49
Location: Market Rasen, Lincolnshire
My Cars:

Post by nick »

Has the car always had the poor running problem since you bought it, or just the intermittant rev counter?
I'm just wondering if the previous owner has fiddled with the injector pump settings to try and disguise the symptoms of an intermittant ecu/sensor problem, before selling the car ??
Dave Burns
Posts: 1915
Joined: 14 May 2001, 05:30
Location: United Kingdom
My Cars:
x 2

Post by Dave Burns »

The rev counter or tacho gets its signal from the engine management ECU, the ECU gets its inputs from both the injector lift sensor and the TDC sensor in the top of the gearbox bell housing.
If either one of these sensors go down the tacho still works and ECU is then in guessing mode as to injection timing I suppose, if both sensors go down the tacho stops and the ECU can't adjust the timing since it is getting no information as to what this should be, with no timing adjustment the pump merely rests at full advance and you get the very clattery diesel knock.
Its a bit unusual for both sensors to go down at the same time, so the fault could be with the ECU or its connecting plug and associated wiring, have a look at the pins of the ECU and the sensor connectors for oxidisation.
Disconnect one at a time, the lift sensor on the injector and the TDC sensor, note what affect this has on the tacho, if none then both are working, if the tacho stops when either one of the sensors is disconnected this means the other still connected one or its wiring is faulty.
The ECU only alters the moment of injection, it doesn't have any controll over fuel quantity.
Dave
JohnS
Posts: 4
Joined: 08 Aug 2004, 22:17
Location:
My Cars:

Post by JohnS »

Just a belated thank you to Dave Burns for the advice given here on 8 August last year. It's been a busy winter and have just got around to forking out the £85 + VAT (at GFS) for the number 2 diesel injector, with the integral lift sensor. All power is restored and the tacho works 100%. Thanks once again for a spot on diagnosis and solution.
Post Reply