Volvo 240 Poor Gas Mileage!!!!

Guest · Post by **Guest** » 21 Jan 2003, 09:12

I just bought my first volvo. A used 1989 240DL with automatic transmission. I love it except for the gas mileage. I have been averaging 15/16mpg. It idles rough after it warms up also. The throttle body has been cleaned and the spark plugs changed with no effect. Any suggestions? Thanks.....

Wes

arete · Post by **arete** » 22 Jan 2003, 08:04

Check the cat to make sure it is still working- not too plugged.
Check your O2 sensor
My '81 gets 20/town.

Cliff · Post by **Cliff** » 27 Jan 2003, 21:07

does the cars overdrive work? My wifes was not working and she thought it was fixed it and WOW it made a big difference

guest · Post by **guest** » 30 Jan 2003, 17:33

I think the overdrive is working. When I push the button on the shifter it drops a gear. there is no tach to confirm what rpm I'm driving at but, just from experience, I'd say it is not a transmission issue.

The garage found the air intake clogged with leaves and ice! Said I was starved for air and what air I was getting was full of moisture. sounded good, but no change in the mileage after that.

They said everything else eg: o2 sensor, maf sensor, catalityc, etc would throw a code on the diagnostic computer.

Today, they replaced the o2 sensor to keep me quiet. Will see if that helps soon.

Thanks....Wes

Guest · Post by **Guest** » 28 Mar 2003, 20:31

New 02 sensor was a success. Now getting 23 to 28 mpg on every tank. It still idles a bit rough and shakes a fair bit for the first few moments after initially starting but clearly this situation has taken a turn for the better. Thanks to all for the suggestions.

Wes

Volvord · Post by **Volvord** » 29 Mar 2003, 09:16

Just a comment for everyone. I get so frustrated at mechanics that rely totally on there little diagnostics computer to tell them what is wrong with the car. The only time a fault code will be generated is when a sensor or system returns a signal that is outside the acceptable perameters. But if a signal is sent that is within range, although totally inacurate, no fault code will be generated. As an example an O2 sensor will work within a range of 0.1V to 0.99V at 0.1V a good sensor identifes a 16:1 air fuel ratio, at 0.99V it is measuring a 12.5:1 A/F ratio. 12.5 is extreamly rich and 16 is very lean but both within range, neither will provide good performance, drivability and will effect gas milage.

Sorry for the rant, but as a mechanic I am embarised by the lack on good old fashoned diagnostic and troubleshooting talent availbale in todays market.

I am glad your problem was located and cured

Volvord 784VC
http://www.telusplanet.net/public/gilesij/Volvord/