Gas Mileage

adollarwodbnice · Post by **adollarwodbnice** » 13 Nov 2007, 08:16

What's this EGR stuff? I heard about that deep creep spray for the throttle body but what else can I do that's really simple to help with this. Tomorrow i'm gonna seafoam my intake, gas, and oil and hopefully that will help especially if it will go through my vacuum line like you said I should check.

calbrit01 · Post by **calbrit01** » 13 Nov 2007, 10:17

The discussion about gas mileage is a mute one, unless there a number of constant factors, especially how the mileage is being measured. Assuming we are all using the same method, i.e the on-board computer, then there are still many different variables. As an example, take my findings:

Approx 95% highway.

Over period of 4 weeks, measured 23.6 mpg on the average reading.

Over a 40 mile journey on the freeway, using cruise at a constant 75mph measured 30mpg.

The results are repeatable.

What we should really do is set down a method for measuring that we can all compare against, which should include factors such as average speed, distance traveled, use on board computer or fill &/or drain method etc. The results may not be 100% accurate, but at least it will give a benchmark for people to compare against.

Heres what I would do:

FREEWAY MPG
Fill your tank.
Reset your average speed, average MPG.
Drive freeway for say 50 miles.
Note your estimated MPG and estimated average speed.
Refill your tank, noting how much fuel you used.
Divide the miles by the fuel used.
Repeat the process.
Take the average of the 2 results

TOWN DRIVING
Same as above, but you may want to reduce the number of miles driven.

AVERAGE
Add the freeway and town fuel used and divide by the total miles. Add the MPGs and divide by 2. See how the results compare.

zenmervolt · Post by **zenmervolt** » 13 Nov 2007, 17:51

Klausc wrote:JRL.
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.

Sounds like something's buggered in your transmission. Mine will downshift as soon as I give it a little more gas, even in "economy" mode. There's nothing at all harmful about having the shifter in "Drive" in the city and if that is causing a mileage problem for your car, then your transmission is suspect.

Post by **JRL** » 13 Nov 2007, 20:40

Klausc wrote:JRL.

Perhaps the problem is a stuck caliper?

Klaus

Perhaps you don't DRIVE.
If you puddle around like that, you're transporting, not driving
I'm in manual mode almost ALL the time

karageorge2 · Post by **karageorge2** » 13 Nov 2007, 21:33

JRL
I believe the post was created to try to improve the gas mileage which is the nature of the suggestions provided. Not to dispute what type of mileage Volvos are supposed to be getting.

However, from all the posts and people I have talked to the 850 turbo wagon should be above 19 mpg otherwise there is probably something wrong. AND that would most probably be in the PCV/EGR system.
Mine is getting over 20 in the city with normal behaved driving unless of course the mpg reading is wrong or I am going blind.

Remember it is a 5 cyl engine. Most turbo 4's get around 25 most v8's around 14 or less. Do a little division and guess about what most 6's get? 19? well a five should be above that and that's really all there is to it.

16 mpg is definitely not normal unless of course you have a huge lead foot or drive in a city like downtown New York where you mainly sit more than you drive. In that case 16 mpg is really good.

If you havent cleaned out your pVC/egr stuff do so because mpg will be the last of your worries.