[Mk2] [Turbo] Rev 2 turbo overfuelling

[2tmike]

Car has been on the drive over the winter and was running fine last year. Now it's still driving well but fuel consumption is crap and plugs black even after a 1k miles use. It's fairly standard - exhaust, filter, decat, tektom board in ecu, but won't go above 22-23 mpg. Last year I was getting at least 25. Any ideas? Cheers
Mike

[Peter Gidden]

Start by doing a diagnostics test.

Check your O2 sensor.

[2tmike]

Thx,
Should have put in the question that there are no error codes showing.
On a rev2 does the O2 sensor actually control the fuelling when the engine is up to tempetature ?

[Steve-O 2007]

have you took into account the cost of fuel now?

£40 used to give me a full tank, now £40 only gives me 3/4 of a tank!!

[2tmike]

sure have...!!!
On motorway driving (no boost) used to get get close to 300 miles on a tank if I was carefull or up to 28mpg. Doing the same trip same speeds in an M3 I get almost 35mpg, Now the MR2's giving 23 at best...like you said, expensive.......
Checked the AFM screw setting and it's spot on so is the timing. Guess there's not much else that you can adjust ?

[rossdymond3352]

Tried a stock ECU?

Cambelt could have jumped a tooth. although it would feel gutless

[2tmike]

Yes I have, It uses slightly less fuel on stock ecu , but still more than it used to last year on std ecu. That's also strange because the Tektom board is supposed to be same as the Blitz access which is claimed to have leaner fuelling mid range. With either ecu tail pipes and plugs are sooty black ! Think valve timing is ok as it still runs fine up to the line in all gears