Fuel guage.

Stuart McB · Unread post by **Stuart McB** » 21 Oct 2004, 20:46

Any thoughts on this [?] . My Xsara gives me good MPG around 340 [:)] befor fill up evey 10 days to 2 weeks. My problem is this morning I watched the guage go from 1/4 full to empty over a mere 17 miles [:0]. Now I usualy go by the milage but this seems to have gotten a lot worse over the weeks. Example 42Ltr of fuel (full on the guage) to a quater full with in 280 miles and then to day a further 17 and in to the empty, light on . I've double checked for poor fuel comsumption and all the usual stuff and all is OK, car runs fine. I'm sure it's a sender problem but not to sure. Any help. I've done a site search and theres a few ideas about 're programme by disconnection' [?]

jeremy · Unread post by **jeremy** » 21 Oct 2004, 21:42

Either its the gauge or it isn't. Why not get an absolute reading by brimming the tank and doing it again after 200 miles and see what has been used. Gauges are notoriously unreliable - our ZX reads in the red with about 5 gallons left in the tank!
If the consumption really has risen - then either the car is going to burn it in which case it will run badly and smoke heavily or its leaking. It could be leaking from the tank (had vent problem on ZX) or elsewhere. you don't say if its petrol or diesel - if diesel it could leak from the leakoff pipes - again had one of those leak on ZX. Have a good look around for fuel on the road or underneath the car or in the case of petrol, smells and stains.
jeremy

Stuart McB · Unread post by **Stuart McB** » 21 Oct 2004, 22:22

Sorry I haven't made my self clear. Car is a 1.6, 8 valve petrol. The MPG is great but the guage drops faster than a 2 bit h**es draws. I know that 42ltrs of fuel should work out to about 400 miles ish with town, city and country driving. So filling up at about 340 to 360 is OK (10days to 2 weeks) but it's just the rate at which the guage drops. I ain't using any more fuel and there arn't any leaks. I've done all the usual checks. The problem is the gauage just drops really fast. I have brimmed the tank and within 50 miles the guage was down by a third, and I still got good MPG before fill ups. I just think the guage is just to enthusiastic (spelling) and is showing a very inacurate tank level.

rotodiesel · Unread post by **rotodiesel** » 22 Oct 2004, 00:33

I've had this problem. In my case (1998 car with electronic speedo) the problem was due to poor connections on the wire "zero Ohm" jumper links on the back of the flexi printed circuit (VDO instruments). These people have an insane method of crimping the wires to an unplated track, which gives a high resistance joint, making the fuel gauge read low. Find the offending track, and bridge out the whole lot with a soldered length of wire. In my case, the bad connection was in the track carrying the sender current, between the connector to the vehicle harness and the little plug-in electronics board for damping the fuel gauge. Have fun.
rotodiesel.

Stuart McB · Unread post by **Stuart McB** » 22 Oct 2004, 01:11

Thanks for the tip.

monkeyman · Unread post by **monkeyman** » 22 Oct 2004, 01:18

Hello!
If your xsara is a later multiplexed type, there is possibly a download from your main dealer to sort it out. On a multiplexed Xsara the sender unit in the tank works only when u switch the ignition on. When the engine is running the injection ECU calculates how much fuel you have used, so the BSI using this info adjusts the gauge. I drove a xsara, the low fuel light came on, and i ran out of fuel within a couple of miles! A download sorted that out!

Stuart McB · Unread post by **Stuart McB** » 22 Oct 2004, 01:20

It's a 1998 Mk1 - does this have a multiplex wiring loom?

wheeler · Unread post by **wheeler** » 22 Oct 2004, 03:43

no it doesent have multiplex,try disconecting the battery while the ignition is switched on for 10 seconds or so & see if that helps.this model cant be downloaded.