Over fueling?

[bubs]

Ok on a conversion which I recently helped with 1UZ-FE into a Nissan Patrol we are having problems with how much fuel the engine is using

It is wiried up using a Wolf 3D version 4 and origianlly was using the map of another patrol conversion which gets around 6.5km / l of fuel towing a 1500kg trailer around

The second patrol is getting 4km / l of fuel not towing

First patrol is manual, second is auto

The second patrol has now been independitly (sp?) dyno'd now but still uses as much fuel.

The only difference between the two fuel systems is the second uses a bosch fuel pump from a Holden VL Turbo fuel pump and the first uses a stock fuel pump from an EFI 3.5 rover.

Question is

What can be causing such a huge increase in fuel usage between the two different vehicles

 

[Peewee]

If it has been tuned PROPERLY it should be getting better than 6.5km/L

It obviously wasn't tuned properly.

Are the spark plugs black?

Don't rule out the possibility of a fuel leak

 

[bubs]

It has brand new spark plugs, we have checked all over the fuel system for a leak no luck finding one

Any more suggestions , this is worse fuel economy than the original 6cyl 4.2 litre

 

[Peewee]

Its back to tuning dude.

If the air coming out of the exhaust is a good air/fuel ratio, then the excess fuel isnt coming out of the injectors, so it must be a leak.
If you have no leaks, then the car must be running rich.

 

[Lambo]

Thirsty 1uz

Hi bubs, i have read somewhere that after a conversion the ECU can go into limp home mode, this will make it drink fuel, maybe someone here knows something about it and what causes it.
Regards
Lambo

 

[Peewee]

He is using aftermarket.
Its not in limp mode.

 

[bubs]

it is a computer / tuning problem it went back to the tuner, he went for a 40km drive with his laptop plugged in, as soon as the accelerator was depressed even the slightest the computer was just pooring the fuel through

hope fully it is fixed now

thanks

 

[Peewee]

Good to hear.

Why didn't it do this on the dyno?

Sounds like the MAP sensor may be faulty or something.
Whatever it was, it was probably something simple.

 

[bubs]

i am not sure, i wasn't there when it was done