People, I'm not sure it's limited to the Corsa. I have a Vauxhall Zafira Elegance 2001 which I have owned from new and it has only covered 25,000 miles. The car has the technical pack which adds a fuel computer which indicates the range (distance) that the fuel indicated on the fuel gauge will give you.
Both the fuel gauge and the range indicator occassionaly take a nose dive when travelling typically on motorways at around 60mph , regardless of intial fuel reading . I have removed the tank and replaced the sender unit which gave a part improvement, but not significant. I have buzzed out the earth loop at the sender wiring, good for 2AMPs! I have had Vauxhall run diagnostics on the dash ECU and also reprogram it to the latest software. Still no good.The problem affects both the fuel gauge and the range digital readout so the fault must be before the dash board circuit split for the two gauges - ie the gauges are ok. Which leaves only the wire which runs from the rear to the front of the vehicle! Then this morning (20/4/05) I made a discovery. The problem was occuring typically on motorways, but at the same part of my journey every time. Every time I draw up parallel with a local TV/mobile transmitter mast! .. and there are plenty of those dotted around. Guaranteed every time, except for when the tank is absolutely full - then it would read correct. In other words the fault is pointing at the ECU which is seemingly suffering from the wire running from the rear to the front of the car, acting as an aerial! I am a fully qualified electronic design engineer by trade and this is entirely possible. The only way round it would be to add some filtering at the ECU. I intend to employ a 'well designed' parallel system in the car feeding from the same sender to verify my conclusion. I can then check the reading of the second system as the in car system fails. If it proves true, then an ECU modifcation to filter out mobile phones etc would need to be applied.
Gary, April 2005
