91 Fuel Computer Accuracy
Thread Starter
Drifting
Joined: Sep 2009
Posts: 1,765
Likes: 1,507
From: Willis, tx
91 Fuel Computer Accuracy
My six speed roadster never quite got the mileage that I thought it should. After owning the car for ten years I final checked it out by measuring the actual quantity and the actual distance. First of all my speedometer and odometer are dead accurate. So it turns out that the onboard fuel computer is about two mpg low. Last month on a 1600 mile trip to see the eclipse the computer showed 24.2, actual manually measured was 26.6. Since then I have checked weekly my daily driving which is 25/75 city/highway. Generally shows about 18.5 and actual is about 20.5. By the way the trip was mostly above 70 mph with A/C. Over all my old high mileage C4 is still one of the best looking Corvettes and a pleasure to drive.
Last edited by polo91; Sep 24, 2017 at 12:37 AM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
It's a calculation based on expected fuel use under the engine operating conditions. There are a lot of variables. I have never seen one that was 100%, they can be close. Myself I worry more about the range feature...normally when I'm in the middle of nowhere.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
I agree with ddahlgren that I have heard it is based on injector pulses to calculate the amount of fuel used. There are some things that can alter the actual from the expected flow.
I have also heard that it can be adjusted in the tuning.
On my C4's most have been pretty good. My '85, '87, '88, '94 and '95 were very close although my '96 reads about 2mpg lower than actual.
Both of my '99's read about 2mpg higher than actual and on the C5 section this seems to be pretty common.
I have also heard that it can be adjusted in the tuning.
On my C4's most have been pretty good. My '85, '87, '88, '94 and '95 were very close although my '96 reads about 2mpg lower than actual.
Both of my '99's read about 2mpg higher than actual and on the C5 section this seems to be pretty common.
