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MG MGF Technical - fuel consumption gone up 25%
for some reason my MGF's fuel consumption has gone up considerably (25%) from 8 litres 10 litres per 100km.
It occasionally smells for petrol, but has done so since the very start (been to lazy to fix this). I think it started to smell for petrol during driving lately (on twisty roads) though.
I checked for any fluel leaks, with engine running idle and at 4500 rpm, but could not find any, so I assume it's a MEMS thing. The dealer thinks it might be a problem with the engine coolant sensor that feeds MEMS (car does not overheat), another thought might be the Oxygen Sensor (I have a spare part, but could not change it for lack of a crowfoot spanner :-().
Is there anything else I should check before passing it to the dealer to sort it out (costly)?
The car's a 1997 MPi, Trophy TB, oil cooler, K&N panel filter. My driving style has not changed, only the fuel consumption :-)
|Andreas, when was the last time the airfilter was cleaned? This might be worth doing in any case as a precautionary measure.|
|It was cleaned approx 15000 km ago, but I'll clean it this week to be sure.|
The fuel consumption has not risen steadily, but jumped from 8 to 10, so I suspect something has broken.
|Andreas - any sign of over heating in slow moving traffic or fast idling when warm?|
Fuel consumption frequently goes up when the ECU water temperature sensor gives up the ghost and persuades MEMS that the engine is still cold: IACV opens - effectively the same as running choke on a classic MG = greater fuel consumption.
Not a fault that shows up readily on Testbook. New sensor is 10 quid, so again, might be a case of replace and see.
|Rob, no overheating at all (but I rarely get into slow moving traffic), the oil-cooler might come into effect here, keeping the engine cold?|
Thanks for your explanation, I'll give this a try tomorrow. The dealer has the sensor on stock, so I should be able to see any results over the weekend!
|Seized Brakes ?|
|Just to make sure I got the correct part...|
The sensor I got from my dealer has the part number MEK100060 (website says it should be GTR206).
It does look like the one on http://www.mgfcar.de/sensor/index.htm (first picture) though, brown coloured.
I asume the part numbers have changed?
|Andreas, you may be right about the part number, but sadly I do not have access to a parts manual to verify. If it looks like the GTR206 (brown) sensor shown on Dieter's page above, then it should be the right one.|
More here too: http://www.mgf.ultimatemg.com/hgf_pages/related_problems_overheating.htm
Although note that you don't need to remove that spring clip: pushing it in is enough to release the sensor. :o)
|Andreas, Yes the thing in the picture is the Coolant Temperature Sensor.|
I have just had a similar problem fixed although my car would not actually start when the engine was hot as the Sensor was failing and reporting that the engine was at -47 degrees and flooding the engine with fuel, hence my fuel consumption went up massively.
Change the Sensor and you should be fine.
I had a similar fault on a Golf which was a broken wire to the Lambda probe, the car drove fine but had visible black smoke when reved, the mileage went from 300 to 400 miles on a tank full when fixed.
Removal of the probe probably means removing the manifold first, I have changed one, but it was tight. A decent dealer should be able to fault find to tell you which sensor is faulty.
This thread was discussed between 11/06/2003 and 16/06/2003
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