Gas Mileage

gtg737m · Post by **gtg737m** » 12 Nov 2007, 05:43

Hello,
I have a 1994 850 Turbo wagon and I'm averaging 16 miles/gallon in my car. I drive mostly in the city. Does anyone know what I need to do to improve my gas mileage? How often is it necessary to tune up an 850 turbo? Mine was tuned up 20,000 miles ago, I changed the air filter, gas filter, spark plugs, rotor cap, spark plug cables. I change the air filter every 6,000 miles and the oil every 3,000. Any ideas? I'm using th best quality gas now that it is a turbo. What must the tire pressure be in this car? Thanks.

DieselDoNicely · Post by **DieselDoNicely** » 12 Nov 2007, 10:25

Buy a turbo diesel 850, I get 40 mpg(imperial gall), 120 miles an hour plus and its an auto.

DDN

Larmor · Post by **Larmor** » 12 Nov 2007, 11:35

Recommended tire pressures will be printed on a sticker on the inside of the fuel tank cap door. It's 36 psi all around for mine.

Klausc · Post by **Klausc** » 12 Nov 2007, 14:20

Unfortunately, the USA does not sell diesel engines.
You should be getting around 19-21mpg, unless you drive short distances and the engine never gets very warm.
Plug wires and distributer cap/rotor are normally good for 100K + miles, the plugs for around 30K miles. Air filter in the city, about 2 years.
So you need to check the vacuum elbows for cracks and very soft to the touch. Your forward O2 sensor may be slowly going out. Clean out the throttle body.
And do not use D on the city streets... that lugs the engine and waists gasoline before the TCU causes you to down shift.

Klaus

adollarwodbnice · Post by **adollarwodbnice** » 12 Nov 2007, 19:00

My car seems to be getting EXTREMELY poor gas mileage and I can't figure out why. I bought seafoam to potentially help my car run better in a few different ways but I want to find out how to use it on the oil, gas, and intake better before I do it. I don't know what order to do each in and when to do it. I payed 40 bucks to fill my tank and I got about 300 miles for 18 gallons...., doesn't make sense....

sixdown · Post by **sixdown** » 12 Nov 2007, 20:15

Yeah, I pay $55 to fill my tank on premium 93 Octane, and I also only get around 16-17mpg. I have my tires inflated properly, never hit the gas too much, use cruise control, and drive highway quite a lot. My spark plugs are quite new, the wires are fine, the rotor is fine, and the car's exhaust fumes smell extremely rich. Other than the throttle body, is there anything else that could have it running rich? The O2 Sensor is still good.

karageorge2 · Post by **karageorge2** » 12 Nov 2007, 20:50

if you have not cleaned out your egr, intake, throttle body, oil trap, pcv at turbo you need to do so. Iit can make quite a difference. when I bought my 940 850 tw it was getting 16 mpg and the egr system was pretty clogged up with 113k on it. Took egr and throttle body apart and cleaned out with throttle body cleaner qtips brushes etc. and the mpg went to 21-22 city. (carb cleaner throttle body cleaner etc.) The oil traps on these cars can really wreak havoc on mpg and cause oil leaks etc. I just replaced mine which was a wee bit of a job. Also, vacuum lines to all the above items should be checked for age and clogging.

Have fun!

Post by **JRL** » 12 Nov 2007, 21:21

Klausc wrote:Unfortunately, the USA does not sell diesel engines.
You should be getting around 19-21mpg, unless you drive short distances and the engine never gets very warm.
Plug wires and distributer cap/rotor are normally good for 100K + miles, the plugs for around 30K miles. Air filter in the city, about 2 years.
So you need to check the vacuum elbows for cracks and very soft to the touch. Your forward O2 sensor may be slowly going out. Clean out the throttle body.
And do not use D on the city streets... that lugs the engine and waists gasoline before the TCU causes you to down shift.

Klaus

Incorrect on most counts.
Most turbo Volvos will get 14-16 IN CITY stop and go DRIVING
Wires and rotors are NOT good for 100K they should be changed at 30K along with the plugs and that last sentence is rediculous

Klausc · Post by **Klausc** » 12 Nov 2007, 22:31

JRL.
No Volvo should get rotten milage in the city or country, turbo or not. Given that the driver does not have a lead foot for the gas and brake, he should still get close to or above 20mpg. Going 0-30mph in rush hour traffic will not invoke the turbo.
I have yet to see rotors and wires deteriorate before 100K miles, even in the desert southwest.
Doing 1200-1500 rpm at 30-35mph and giving it light gas to accellerate in tight traffic is not good for the engine or gas mileage. The tranny will not downshift to 3rd or 2nd without good hard foot pressure. The injector cycle will last longer and the engine will lug. Try it sometime. Without moving the gas pedal and a light throttle, manually down shift to third and watch the speedometer. You will speed up.

Perhaps the problem is a stuck caliper?

Klaus

gtg737m · Post by **gtg737m** » 13 Nov 2007, 07:10

Can the rear oxygen sensor be affecting my gas mileage? I changed the front oxygen sensor 2 years ago now that I was getting a code for it but never changed the one in the rear. Should both be changed at the same time whenever one goes bad? I will clean my EGR valve and throttle body this weekend and see what results I get from this. Anyone knows what's the procedure to clean the EGR valve? Any instructions would be greatly appreciated. Thanks for all the replies.