My Grand Prix 92 GT 3100 is fuel hungry, HELP!!!

[numanabbas]

My grand prix 92 GT 3.1 is fuel hungery. It currently do 7.5 mpg (31.7 liters/100km). I have changed the injector set, and a couple of sensors (MAP & Oxygen sensors). Does anyone know what might be the problem or might have a hint?? This is driving me nuts......
Thanks

[SappySE107]

Thats gotta be running rich or its leaking fuel somewhere. I guess it doesn't smell like gas or you would have said something. Where are you located? A scan of the ECM will probably show something. What is your fuel pressure? How do your plugs look?

[numanabbas]

Thats gotta be running rich or its leaking fuel somewhere. I guess it doesn't smell like gas or you would have said something. Where are you located? A scan of the ECM will probably show something. What is your fuel pressure? How do your plugs look?

Naaah, no smell
ECM has been reset before injector changes
they say everything was fine
About the fuel pressure... no idea
Plugs .... brand new
Located very far... in Emirates the presian Gulf

[mfewtrail]

I would check the ECT(engine coolant temperature) sensor to see if it's functioning properly. They can fail and make the computer think the coolant temperature is very cold which results in the engine running extremely rich.

[numanabbas]

I bought a new one and installed it.
Nothing changed
Still............fuel hungery

Thanks for the guys who responded..
Did anyone get this sort of trouble...and worked it off??????

[gpse3400]

the only other thing would be the fuel pressure and the intake air temperature sensor. If the fuel pressure is too high it would cause some extra consumtion. if the intake sensor were to fail it would do the same thing.There is not much else other than replacing the memcal in the computer with an updated program.. In that case youd might be intereseted in buying the perfromance chip from this site. FYI the stock memcal isnt that expensive at all. Another thing that would make it run rich, is stuck thermostat. All things considering, since this car is a '92, I'd be changing almost every sensor out just because of the age. The onlything left is the KNock sensor..and those usually go deaf thus causing more advance till the computer runs its sesnor test and sees that it failed.

[numanabbas]

the only other thing would be the fuel pressure and the intake air temperature sensor. If the fuel pressure is too high it would cause some extra consumtion. if the intake sensor were to fail it would do the same thing.There is not much else other than replacing the memcal in the computer with an updated program.. In that case youd might be intereseted in buying the perfromance chip from this site. FYI the stock memcal isnt that expensive at all. Another thing that would make it run rich, is stuck thermostat. All things considering, since this car is a '92, I'd be changing almost every sensor out just because of the age. The onlything left is the KNock sensor..and those usually go deaf thus causing more advance till the computer runs its sesnor test and sees that it failed.

Well.... That makes more sense to me.
I will check it with my mechanic this afternoon or tomorrow.
You never know what might come up...
Thanks for those who responded
and waiting as well for more inputs from others who had this experience

[alainman15]

if ur runnin rich check ur exhaust colour. it will be black. ur 02 sensor would also read rich and reduce the time the injectors are open. unless u got a problem with the electronics. that is theoretically speaking. chech ur exaust though get a friend to rev it up.

how are ur driving habits wot alot? if its manual, is it in low gear when it should be in a higher gear? just some things people might not think of.

[numanabbas]

I'll check that
Color OK
Oxygen sensor, fine according to computer reading
Driving habits, just normal
Manual transmission?????,,,,Nahhhhhh, Not in this life

[canuck_corsica95]

wow - my 84 Supra didn't even get mileage that mad and it had a problem with the rear brakes sticking! to me it sounds like a sensor or a group of sensors is totally fubar. either that or it's the ECU

[GT8]

I had a bad fuel filter....

I bought a new one and installed it.
Nothing changed
Still............fuel hungery

Thanks for the guys who responded..
Did anyone get this sort of trouble...and worked it off??????

I have a 1991 Pontiac GTP 3.1 turbo motor in my McLaren M6B-GT concept car and did those little things you mentined. I have a Holly Pro fuel cannister filter I changed and it ran better. Also check your fuel pump pressure.

My car runs the quarter mile at 14.3 @ 90 MPH and that is in drive. I just found out the car boosts much better and will do the quarter exceptionally faster left in second. She does 90 MPH in second with the engine not screaming, go figuire. If I drive it hard in 1st gear, the rev limiter kicks on, I have not found the rev limiter in 2nd as of yet....... Based on a computer that is stock without a Haltec piggy back configuiration, there are it's limits.

I plan on taking the car to the Bonnyville Salt Flats next year to enter into the 200 MPH club. I know whe will do 200 MPH, I am looking for 212.

[85_305]

I plan on taking the car to the Bonnyville Salt Flats next year to enter into the 200 MPH club. I know whe will do 200 MPH, I am looking for 212.

Hopefully you dont think this '90mph car will 200 on the flats