OK, what did I do wrong?
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.
OK, what did I do wrong?
Seems the mileage on my vette has gone way down hill since last year. Last year I made a trip about 3500 miles and I averaged 26 1/2 miles gallon with a very bad miss in it, because of a cracked plug. sense then I changed the oil pressure sending unit, meaning I had to pull off the intake. And changed the plugs and plug wiring. It now runs great, very smooth. But I have made a couple of shorter trip and only get about 22 miles a gallon. Why? It is a 2000 convertible with about 75000. Did I mess something up when I pulled the intake? Thanks for any help.
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.
Oh sorry, 6 speed. I also seem to be running a little hotter. It used to run around 198 to 199 most the time. now it seems to run between 205 to 207 on flat open highway. I know that is not really to hot, just hotter then it used to do.
Last edited by convertible lover; Mar 29, 2008 at 06:40 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Different times of the year the FUEL has different formulations and will give different MPG readings. Like one trip was in the summer and one in the winter. It can make a big difference in MPG readings.
BC
BC
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.
You could be right the long trip was in July. Other wise I am talking about in the last couple of months. But that seems like an awful big difference from 26 with a big misfire down to 22 with running great.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
BC
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.
Air filter is new, it is stock with the top cut out for more air flow. I am not sure how to clean the MAF do I buy a cleaner? Is it a spray? Please explain a little.
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Drifting
Joined: Apr 2007
Posts: 1,891
Likes: 109
From: Texas
St. Jude Donor '12
I would clean your radiator. I bet it is pretty dirty. There are some threads on here on how to do it by taking the fans off and using water then air pressure to get it clean. I just used a water hose with a spray nozzle and manuvered it around and thru the fans. It got it pretty clean and it did run much cooler after I cleaned it.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Remove the air box/air bridge assembly, the filter and spray some cleaner in the MAF through the screen.
I actually use brake parts cleaner but,,,,,,if you want to be "technically correct" purchase some spray MAF cleaner (probably brake parts cleaner at twice the price
) and spray it into the MAF. Just wash out any dirt and oil residue. Let the spray wash out the dirt and then let the cleaner evaporate. Reassemble the air box and see if it makes a difference.
Very easy procedure. Nothing mysterious.
Yea,,,
,,,,you can clean out the radiator but if your not overheating,,,,its NOT going to effect fuel mileage. 
BC
I actually use brake parts cleaner but,,,,,,if you want to be "technically correct" purchase some spray MAF cleaner (probably brake parts cleaner at twice the price
) and spray it into the MAF. Just wash out any dirt and oil residue. Let the spray wash out the dirt and then let the cleaner evaporate. Reassemble the air box and see if it makes a difference. Very easy procedure. Nothing mysterious.
Yea,,,
,,,,you can clean out the radiator but if your not overheating,,,,its NOT going to effect fuel mileage. BC
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.
I have cleaned the radiator not to long ago. I will try to clean the MAF maybe tomorrow if I can get the time. I already have some brake cleaner, if that will work OK. I will see if it makes any difference. Thanks a lot for the help.
Le Mans Master
Joined: May 2006
Posts: 7,869
Likes: 252
From: Hillsboro OR
You mentioned the air filter was new. Was it oiled? I agree with cleaning the MAF sensor. I have actually used a Q-tip with alcohol and VERY GENTLY wiped the sensor elements themselves off. It can make a big difference. 
Team Owner
Joined: Sep 2007
Posts: 21,915
Likes: 61
From: Miami Beach FL
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.
I did try to start the car after I did the intake, and found out it would not run without the air bridge in place. Could I have knocked something out of adjustment? And if so, how would I fix it?
Team Owner
Joined: Sep 2007
Posts: 21,915
Likes: 61
From: Miami Beach FL
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.
looking better
OK, I did just get back from a 40 mile drive. I know not a great test, but will have to do for now. like I said doing the math I was getting 22 MPG, my DIC was reading about 23 1/2. This morning just as I was pulling on to the highway I hit the reset button. When I got there about 20 miles mostly downhill it read 31 MPG when I got back mostly uphill it read 27 1/2 Mpg. So with this short test seems like it did a lot of good to clean the MAF. All I can say is, I am surprised but happy about it. So Thanks a lot for the help.
Thread Starter
Racer
Joined: Dec 2001
Posts: 333
Likes: 1
From: Laughlin NV.