Excessive fuel consumption

[HaydEn]

Hi guys, got an issue.

So I've tried to do a bit of digging but to no avail.

The backstory: I bought an obd2 engine, for my obd1 car. I'm running the obd2 fuel rail and fpr on the obd1 ecu, with obd1 intake manifold.

Before this engine swap I would get 500+km's out of a tank of 98.

However now I struggle to get 250km's

The car has new spark plugs and leads, new air filter, cleaned throttle body.

Only mods are LSD, lightweight flywheel ported exhaust manifolds and intake manifold(at throttle body throat)

Could using the obd2 fuel rail be causing this?

Thanks for any help.

[Zalemate]

I have a fuel problem aswell but i havent got any different fuel rail or anything i get max 300kms out of a tank of 98. Pretty sure its just VR's i think mine runs too rich but im not really sure im hoping when i get a GIAC it may help a little bit

[nightphotographer]

Haha Zale - I think it might be down to the way you drive!

[Mk3 AAA]

From what I know there are some considerable differences between obd1 and 2, you're going to need a Golf Loon, JMac, Peter Jones sort to help you with this one I'd say.

[HaydEn]

Injectors are apparently the same to some, different to others.

Obd1 is 4bar fpr
Obd2 is 3bar fpr

[HaydEn]

I have this unplugged sensor. In yellow colour under the Airbox? Can't find a damn place for it to go.

I am just disappointed as there are 700+Kwaw Gtr's on e85 that get 200km a tank. And I'm not having that much fun.

[VR28LT]

I have this unplugged sensor. In yellow colour under the Airbox? Can't find a damn place for it to go.

I am just disappointed as there are 700+Kwaw Gtr's on e85 that get 200km a tank. And I'm not having that much fun.

im not sure what that yellow plug is for but i have the same one unplugged so i dont think that is your drama

[ziggy_jacob]

are you on the limiter?

[HaydEn]

Haha that's good to know bima. I just thought, why the hell would vw have that there.


I'm in full fuel saving mode, obviously this is still town driving not highway. But around town my mfa used to read 6.5-7.2 now I struggle to hit 12's.

[LeaMedhurst]

Haha that's good to know bima. I just thought, why the hell would vw have that there.


I'm in full fuel saving mode, obviously this is still town driving not highway. But around town my mfa used to read 6.5-7.2 now I struggle to hit 12's.

6.5 !!! that is over 40mpg in the old language !!! are you sure your old engine ran on 6 cylinders !! My car will struggle for 12's as well with the air con on. When I potter about town with the AC off I can get down to 10's.... VR6's where never famous for their fuel economy.