Kangeroo & low mpg recently

leonardo · Post by **leonardo** » 10 Aug 2005, 16:47

My Saxo has started getting a little bit kangerooey recently and when driving it sometimes feel like the car is being held back. Couple to this have been getting shocked at how often having to go to petrol station, even when doing more economical motorway driving at 65ish.
Has anyone any ideas? I only had it serviced 7 weeks ago ...

Post by **RichardW** » 10 Aug 2005, 17:03

Rough running coupled with high fuel consumption is usually a sign that the coolant temperature sensor is kaput, and the ECU thinks the engine is cold all the time and is effectively running with the choke out. There might be 2 sensors on the head / stat housing, one feeding the ECU the other the temp gauge (if fitted). For some reason I think the ECU sensor is blue. Find it and measure its resistance engine hot and cold. If the two figures are not markedly different (or it reads 0 or infinity ohms cold) then change it.

leonardo · Post by **leonardo** » 10 Aug 2005, 17:12

Thanks Richard - would this be fairly cheap to fix?
Also could this be related to the temp gauge always being close to the red line so that even when stopped at lights for about 15 seconds you hear the fan come on?

jeremy · Post by **jeremy** » 10 Aug 2005, 21:33

Unlikely - if the thing is supplying a rich mixture as for a cold start it will tend to cool the combustion. (In my youth valves would burn out if an engine ran lean!)
Perhaps the temperature gauge is doing its job - feel the radiator and see if its cold in parts when the engine is hot - especially at the bottom. In any case a flush won't hurt and may clear blocked bottom tubes.
jeremy

leonardo · Post by **leonardo** » 15 Aug 2005, 15:22

Got a diagnostic run and found it was the sparkies misfiring again. I had 1 replaced last year 2 weeks after I got it. I suppose it is just a wear and tear thing.