Ok, I have read some posts here on the fuel mileage but wanted to get some feedback on my specifics.

-95 Turbo wagon Auto and only getting around 20 MPG.
Not ideal conditions for saving gas, since mainly 6-7 miles commute by my wife so I'd guess not fully operating temp on engine-although the gauge shows normal / not low.
But still it's mainly highway and I did do a drive to the airport recently to pick up my wife which is about 35 each way and the average on the dash only moved up to maybe 20.5-21 mpg. (I am using the dash read out fro mileage figures, not manually calculated).
We are in Northern California, so not really cold, been mostly in the 50's F lately.
Not really fast driving or a lot of accelerating, pretty relaxed / normal driving.
First tank was on regular by mistake, but now mid grade gas.

I would have hoped to get at least around 25 mpg given above conditions...

Am I to optimistic or could there be some issues causing less than optimal mileage?

I did tune -up recently (spark-plugs, rotor and cap - wires measured fine resistant), also recent oil change Mobil 1 Synthetic.
Air-filter was not replaced since it looked pretty clean.

Tire pressures ok around 35psi.
No check engine light.

I have seen people here changing o2 sensor for better mileage...is there a way to test the o2 before buying a new one and which o2 sensor affects the mileage, I think there are more than one right?

I also saw some replacing the thermostat...which temp rating to go with from my conditions? My engine temp shows normal

Any other ideas on how to improve the mileage?
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-95 850 Wagon Turbo (136K) -93 960 Wagon (133K) -68 122 (300+K) [-97 M3 (233K) -69 Firebird 400 (110K) -81Kawi Gpz 1100cc -05 Triumph Speedtriple 955cc] /That's all for now folks :) Lars

You should check your mileage by computing it yourself. I charge all my gas and it is really easy to write the odometer reading on each slip. You can then check the mileage on 5 tank fulls pretty simply.

Not using premium may be part of your problem. I do not know for sure about the 850, but the Regina system would add extra fuel to cool the cylinders when a knock is sensed,

Everyone assumes that the knock sensor changes the timing, but that will not work because the problem is the mixture igniting before the ignition system sparks!

In my experience, premium is worth 2-3 MPG at least.

Some "experts" like Consumer Reports advise people to use lower grades of fuel because cars have knock sensors - but I have never seen them cite any study that I can read.

Besides - older cars are more prone to knock than the new ones that they test.
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'96 855R,'64 PV544 driver, '67 P1800 basket case, '95 855, '95 854, the first three are mine, heh, heh, 485,000 miles put on 9 bricks

I usually get 17-20 mpg in the city, 25-27 on the highway (light foot) and 22-24 on the highway (heavier foot). Tires at stock inflation pressures (36F 41R).

Overall mixed over the last 5 years is probably around 21 mpg. A recent new o2 sensor has helped not only with the mileage but with other drivability/response issues that were present.

Also note that I installed the IPD stage 1 ECU about a year ago with no change in average MPG.





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Zack Silver 83' 242Ti (230k)

Important items I forgot on the last message:

1994 Volvo 850 Turbo Wagon
Automatic, sport mode 90% of the time
196k miles
Location: Seattle, WA
Shell 91 octane on all fuel fillups
No roof rack or extra weight in the car
Stored in heated garage (55F min temp), fast warmups



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Zack Silver 83' 242Ti (230k)

Check the rubber fuel line that runs above the head. Mine had a leak, which was real hard to diagose, as the fuel landed on the hot valve cover. An imediate 15% mpg increase once fixed.

I commute 8 miles one way into the heart of downtown Chicago and see 18 - 20 mpg depending on weather and traffic. A recent drive back from St. Louis yielded 27 mpg at 85(+)mph.

Your mileage does sound low, bad plugs or a temp sensor will both impact mileage. How old is your coil? Replacing mine with the IPD version was a big improvement.

Thanks for ideas. Will have a look at the fuel line you mentioned.
Plugs are new, recent tune-up. Age of coil, no idea, probably stock - I have only owned the car a few months.

Even my NA 95 wagon only gets 20-22 around town and on my commute - about 11 miles each way (no highway driving). There are extremes. For example, in the middle of a New England winter where I let the car warm up a little before driving I might only get 19 mpg, so my local driving mpg with a NA is similar to what you guys get with your turbos. Highway driving is a different story as I can get 30 MPG on a long drive averaging about 73-74 mph.

Klaus, I believe the turbos are rated for a mile or two less per gallon?

Turbos are indeed rated lower on highway mileage. My problem is comparing my mpg to others, I never go under the speed limit except in residential areas or school zones.

When I first got my R, I got 28mpg at 78mph average speed, a 7 hour trip. It already had 105K miles on the clock. The best I ever did was a day trip on secondary roads, averaging 30 mpg and 60 mph.

Klaus
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Volvos should be saved from the junk yards, not donated.

25 mpg? Sorry, but I think that's a fantasy the way your car is being used.

It sounds like yours is used about the same as ours. Here in CT my daughter uses our '95 854T. She puts on about 15 - 20 miles per day. About 8 of those are on the highway. She is not a lead-foot by any means and is usually going between 100 and 700 ft. above sea level. Normal is only about 18.5 mpg average.

Mostly I blame it on the 10% ethanol fuel that we are FORCED to use. We lost 20% of our mpg when that environmentally friendly fuel was jammed down our throats (well, down the throats of our intakes anyway).

What a bunch of BS just to please environmentalists and corn growers. Use more fuel, pay more for the privilege. Ugh.

Most of us have been using 10% ethanol for the past 20 years, the mpg figures posted on the window sticker reflect this.

I live in the suburbs, the grocery and other stores are about 3 miles away. With my 1998 R, I still averaged 20-21 mpg local driving. Then when I get on the not busy highway and set the cruise at 75mph, I get 26-28 mpg. That's with a loaded car.

Granted, it is not I-95, and the hills around here aren't quite as steep as CT. But commuting a short distance with a cold engine is hard on the engine and mpg. I used to live in Avon and Glastonbury, with in-laws in Greenwich.

Klaus
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Volvos should be saved from the junk yards, not donated.

Don't forget to flush the tranny fluid once in a while.

The next time you do a 35 mile trip, reset the MPG to zero and put the car in drive.

The relatively short commute will not heat things up enough to get a good mileage rating. The first mile will be at colder temps and fuel consumption will be poor. A lot also depends on driving style and conditions. At full boost, the mpg will be around 5mpg. On long downhill stretches with the foot off the gas, you will see 99mpg.

Don't jump to the conclusion that the O2 sensor is getting slow to respond, at least not until your mpg drops below 18 mpg.

Klaus
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Volvos should be saved from the junk yards, not donated.