MK1 Cab.2ltr 16v - Thirsty as f**k

[mr.h]

Hello Chaps.
Wonder if anybody could give me some ideas about a little problem............

I recently treated myself to a Mk1 cab (mid life crisis if ever there was). It's a lovely little car and I'm over the moon with it and as an added little bonus it goes like stink.

My problem is that it gets through petrol like there's no tomorrow.
I calculated the mpg after driving like my nan for a week, and assuming that the milometer is working properly it returned under 25mpg !!

I believe that the  car began life as an imported 1800 GLI (the history is all a bit sketchy). Then at had an 1800 16v put in (from an 87 Jetta I think). Then last christmas it had the 2 litre put in due to the 1800 expiring.

If I were to assume that the ECU from the 1800 16v was left in, would that be something that could make a difference??

I've checked for leaks as best I can, but can see nothing obvious, so just wondered if anybody here had any suggestions before I take it to the garage.

Cheers

[rubjonny]

Ideally you need access to a gas test analyser to check the CO%, my guess is this is a bit rich.

It could be that the WUR was tuned to give more fuel over the rev range, which is a popular mod on the 16v to give you a bit more poke
Thats where my knowledge on the 16v ends though unfortunatly, but I'm sure someone else will be able to give you some more pointers!