getting horrible milage outta my inline6, or am i expecting too much?

[middle school]

I have a 91 Fairmont 4dr, with a 200ci inline 6/auto tranny combo/7.5 rear with 2:73 gears. engine has a 1bbl autoline carb, no smog pump, no cats and a 2chamber flow on the exhaust.

what kinda mpg should I expect? I drive the thing like grandma and the only weird thing its doing is it barely gets to 160degrees on a 30min drive in the city but i always thought that low coolant temps don't really affect a carb'd engine as much as an efi motor.

[middle school]

couple pics of the car. and no i am NOT driving with the Air conditioning on or anything stupid like that.

[ukravit]

Your timing needs to be checked/adjusted. also make sure your vacuum advance hose is connected to ported vacuum.
The temp issue will have an impact on fuel mileage. thermostat might be a 160 or it may be stuck open.
Tire pressure between 35-40 always got best mileage for me going back to the late 70s early 80s, just have to watch for wear in the middle of the tire.
15-17 in town is average for the 200 six. you can bring that up to 17-19 with careful attention to driving style and good tune.

[middle school]

Your timing needs to be checked/adjusted. also make sure your vacuum advance hose is connected to ported vacuum.
The temp issue will have an impact on fuel mileage. thermostat might be a 160 or it may be stuck open.
Tire pressure between 35-40 always got best mileage for me going back to the late 70s early 80s, just have to watch for wear in the middle of the tire.
15-17 in town is average for the 200 six. you can bring that up to 17-19 with careful attention to driving style and good tune.

I also have 15's with tall tires, would that change anything?

thermostat is a new 180

[middle school]

pics of vacuum on distributer

[ukravit]

If you can get a vacuum gauge this may help you a bit
http://classicinlines.com/Vacuum.asp

[rbohm]

with all my inline sixes, i averaged 19mpg pretty much all the time. be careful putting on taller tires, as that will have an effect on your speed o meter. and if you dont correct the issue, your fuel economy will be artificially low.

[middle school]

with all my inline sixes, i averaged 19mpg pretty much all the time. be careful putting on taller tires, as that will have an effect on your speed o meter. and if you dont correct the issue, your fuel economy will be artificially low.

So it will only seem like I am getting bad mpg economy when really it's good?

[Travis T]

Check your speedometer against a GPS to see if it's reading accurately since the tire change.

[middle school]

Check your speedometer against a GPS to see if it's reading accurately since the tire change.

just checked it and my cars speedo reads about 2-3 mph slow... what does that mean?

[ZephyrEFI]

New parts can still be bad. Your car should definitely be warming up.

[middle school]

New parts can still be bad. Your car should definitely be warming up.

whats the details on this? it doesn't smoke or run rough. she is a quiet as a mouse and smooth as a babys butt so I don't get why it running cool would matter? I need some a detail explanation or a link to one please

[Travis T]

just checked it and my cars speedo reads about 2-3 mph slow... what does that mean?

It's pretty darn close, that means your new wheels and tires haven't messed up anything and you can trust your odometer to check your mileage.

[mustangxtreme]

I'd check the thermostat and make sure it is working properly. Then check the timing. You may be able to run more advance than stock which will help increase the mileage.

[Metalbass1979]

Get rid of the catalytic converters. It will improve power, sound and mileage. I hate those things. They make better corks than some corks do.

[Travis T]

He doesn't have a converter anymore.

[ZephyrEFI]

whats the details on this? it doesn't smoke or run rough. she is a quiet as a mouse and smooth as a babys butt so I don't get why it running cool would matter? I need some a detail explanation or a link to one please

Thermostat. Your engine can't burn fuel as efficiently if it doesn't make it up to operating temp, as has already been said. I'd maybe even slap another one in there. When you get to your destination, if you squeeze the upper radiator hose, is there hot coolant in it?

[middle school]

I'd check the thermostat and make sure it is working properly. Then check the timing. You may be able to run more advance than stock which will help increase the mileage.

advance the timing? I want to be able to run 87 octane...

[rbohm]

advance the timing? I want to be able to run 87 octane...

no problem, you just advance the timing until you get detonation with the fuel you want to run, and then back off until the detonation goes away. you should pick up a few ponies, and about 1-2 mpg.

[mustangxtreme]

Most cars can run a few more degrees of advance. Try 1-2 degrees at a time. What I found works to check for detonation is to manually shift the transmission to 2nd gear at about 35mph and then floor it. If you don't get any detonation, take the timing up another degree or two. Take the timing up until it rattles and then back it off a couple of degrees.

[PaceFever79]

Another mpg tip is make sure carb idle mixture is spot on...

If it's too rich, you can waste a lot of gas sitting at lights and in traffic idling.

[1985-Dominator]

What have you done on the intake side to give it all the air it needs?

[middle school]

I just did the numbers and 5 gallons of very lazy driving delivered 60 miles.

What have you done on the intake side to give it all the air it needs?

huh? like what? did you look at the pics? what am I supposed to do past what the factory 1bbl carb needs?

[rbohm]

I just did the numbers and 5 gallons of very lazy driving delivered 60 miles.

12mpg?!?!?

huh? like what? did you look at the pics? what am I supposed to do past what the factory 1bbl carb needs?

you can put on an open element air cleaner, advance the ignition timing, tune the carb, check for vacuum leaks, etc.

[middle school]

12mpg?!?!?



you can put on an open element air cleaner, advance the ignition timing, tune the carb, check for vacuum leaks, etc.

this is the only thing that fit and it was so tiny my ex girlfriend would laugh lol.

http://shop.mr-gasket.com/air-and-fu...lnr-4-dia.html
http://shop.mr-gasket.com/media/catalog/product/cache/4/image/370x/9df78eab33525d08d6e5fb8d27136e95/4/3/4354.jpg