Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

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 H

Andreas, when was the last time the airfilter was cleaned? This might be worth doing in any case as a precautionary measure.
Rob Bell

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 H

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 Bell

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!
Andreas H

Seized Brakes ?
S Laithwaite

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 (first picture) though, brown coloured.

I asume the part numbers have changed?
Andreas H

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:

Although note that you don't need to remove that spring clip: pushing it in is enough to release the sensor. :o)

Fingers crossed.
Rob Bell

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.


Hi Andreas,

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.


Alastair McLeod

This thread was discussed between 11/06/2003 and 16/06/2003

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.