Xantia Running Probs

rossnunn · Unread post by **rossnunn** » 20 May 2004, 03:06

It's a 1.8 16V.
It seems to be misfiring, at first we thought it could be a fuel problem and checked the inline fuel filter to discover the petrol out of it was very black, so changed it and assumed this would fix the problem after it had been flushed through with a tank of fuel.
Its now on its 3rd.
Have changed the spark plugs and had the ECU checked, its reading no faults.
Would have said it was a HT lead but on the 16v there all built in with what look to be coils in the spark plug cover.
This problem has only started after the silencer fell off and a new one fitted (big bugger too!).
Have heard rumers off the lamber sensor remapping the ECU because of the lack of back-pressure or some thing. But have no idea how to get it to remap again if this is true.
Oh and the fuel economy has falled, it now does about 50-60 miles on £10 - it used to be around 100-120.
Any ideas folks??

Stempy · Unread post by **Stempy** » 20 May 2004, 05:09

Don't think the ECU will be remapped as such. If the lambda sensor fails the ECU may well have a default map which it switches to in the case of a sensor failure, a kind of get you home mode. The default map will tend to be less economical, but in this case a fault code should be registered indicating where the problem lies. Curing the fault and clearing the fault codes would return the ECU to it's normal map.
I have been having misfire problems on my V6 which uses similar coil packs Having attached it to an analyser it showed that one of the coils was taking twice as long to charge as the others and I have since been told by a dealer that coil packs have been known to fail, although it could still just be down to HT tracking. As soon as I have time I will take it in and take up their offer of trying another coil pack to see if that makes any difference.

rossnunn · Unread post by **rossnunn** » 20 May 2004, 22:55

interesting,
so any idea why it would happen as soon as the exhaust was replaced??

Stempy · Unread post by **Stempy** » 21 May 2004, 00:47

Have you checked the fuel pressure? Maybe a fuel pipe could have been pinched during the exhaust or filter replacement.