Volvo 850 Made from 1993 to 1997, this Volvo line was available in both a wagon and a sedan, both with were graced with several trim levels.

850 Poor gas mileage - Tips to improve mpg...

  #41  
Old 05-01-2011, 07:40 PM
Senior Member
Join Date: Apr 2011
Location: San Juan, Puerto Rico
Posts: 203
Default

Drove another 20 miles today, its been raining, so the outside temp is a lot cooler, city/city highway was from 18 to 19 mpg, have not done anything to the car yet, still is a good improvement and more "real" that before, maybe leaving the car running for a few minutes just throws those low readings??
 

Last edited by rspi; 05-01-2011 at 07:52 PM. Reason: typo
  #42  
Old 05-04-2011, 10:34 PM
matt01's Avatar
Senior Member
Join Date: Nov 2009
Location: Montreal, Canada
Posts: 621
Default

i just bought a new OEM t stat.. anxious to see if it improves.. my cars bottom of the barrel bad on gas at around 15.5 MPG.. it cant hurt!
 
  #43  
Old 05-05-2011, 10:16 AM
Junior Member
Join Date: Apr 2011
Posts: 2
Default Improved mileage

I had posted my problem with poor mileage, despite the new o2 censors and the remanufactured MAF censor.

Well I took it to a garage where they knew what they were doing “Burtons Automotive in Fredericksburg, VA”. The MAF censor was bad even though I had bought it three days earlier from Advanced Auto Parts, "they gave me a full refund for the bad one even though I had lost the receipt". The issue was actually a cracked vacuum T beneath the throttle body, along with the MAF. So with a NEW "not Remanufactured" MAF censor and a vacuum line / T connector I am up to 25.23 MPG. I divided miles driven between fill-ups "using the trip-odometer" by number of gallons used.

All said and done I have replaced 2 Oxygen censors $125 each, 1 MAF censor "twice" $235 for the new one, 5 spark plugs $15, 1 air filter $14, some new vacuum lines and a plastic T connector $150, and 1 PCV system cleaning $350.

I now have no check engine light and enjoy roughly 378 miles travelled to the 15.03 gallons used. When I had previously gotten about 300 miles to a tank! It has been about a week and some 400 miles driven since the repairs and all is well. Ps. I do 75 to 80 mph highway and am trying to tame my heavy foot.
 
  #44  
Old 05-07-2011, 01:01 PM
Senior Member
Join Date: Oct 2010
Posts: 153
Default

Originally Posted by the detail man View Post
I didn't think our cars ran on regular gas. I always use premium gas.

1995 t5R
needing to use premium is a farce, octane only means the rate in which gas burns and in 1975 it was manditory that ALL cars run on low octane
 
  #45  
Old 05-08-2011, 06:11 PM
Junior Member
Join Date: Sep 2010
Location: Iowa
Posts: 9
Default

I just got home from a 2000 mile business trip.
It was 90+% highway miles and I go 8-9 mph over the speed "guidlines". Averaged ~75 mph on the highway.
I got 26.2 mpg overall on my 96 850 T5. I am quite pleased with that.
 
  #46  
Old 07-26-2011, 06:06 PM
rspi's Avatar
Administrator
Join Date: Mar 2009
Location: Albuquerque, NM
Posts: 15,762
Default PCV and gas mileage...

Originally Posted by boldtu View Post
RSPI: very impressive

my wife says that she never uses the turbo. although I think her average speed is around 20 mph. The PCV system has never been touched, could that effect the mileage at all? I will replace the plugs, wires, dist cap, see where we are then. Thanks for the help guys.

chet
I don't think that changing the PCV will help with gas mileage but it won't hurt. When one of those lines are loose it causes the car to run rich so if it's plugged it may be a gas sipper.

As for your wife not using the turbo, that's not possible, maybe she doen't go in boost much. The turbo always spins. I do believe that your PCV system is effected in relation to how often you go into boost. I think a car that doesn't boost much will not need the PCV replaced as often.
 
  #47  
Old 07-27-2011, 03:04 AM
Junior Member
Join Date: Jul 2011
Location: Sittard, Netherlands
Posts: 3
Default

Can be a small vacuum leak . My turbo ran a lot better when i repaired the leak on the so called "chrismas tree", a plastic manifold for the little hoses.. On my turbo ...

I also fueled up with a too ritch ethanol percentage once, gave the same effect..

Best Regards, F.
 
  #48  
Old 07-27-2011, 11:18 AM
Member
Join Date: May 2008
Posts: 98
Default

Originally Posted by dwillcoxdc View Post
I am new to both this forum, and Volvos in general.

I am having some of the same issues with poor mileage. My 1997 N/A 850 is reading "bank one to rich". I have "in the last week" replaced the MAF censor as well as the plugs and both o2 censors. Last night I searched for an intake leak and found none! I visually inspected as well as a starter spray search with the car running. I have reset the ECU after every new part by leaving the battery terminal unhooked for a half hour. But after an hour or two of running is seems to come right back. Any thoughts??
I was getting this same code on my 97 850. It had approx 276,000 miles at the time so I didn't care about it too much. This may be coincidence but I put a new PCV kit in it and not right away but a few weeks later (didn't change anything else) the code cleared itself. PCV system had never been replaced.
 

Last edited by jrmcgove; 07-27-2011 at 11:19 AM. Reason: Forgot a the last detail
  #49  
Old 07-27-2011, 11:21 AM
Member
Join Date: May 2008
Posts: 98
Default

Originally Posted by matt01 View Post
actually this is false, trucks leave a draft a long distance behind them.
It is true according to the Mythbusters
 
  #50  
Old 07-27-2011, 11:26 AM
Member
Join Date: May 2008
Posts: 98
Default

Originally Posted by dwillcoxdc View Post
I had posted my problem with poor mileage, despite the new o2 censors and the remanufactured MAF censor.

Well I took it to a garage where they knew what they were doing “Burtons Automotive in Fredericksburg, VA”. The MAF censor was bad even though I had bought it three days earlier from Advanced Auto Parts, "they gave me a full refund for the bad one even though I had lost the receipt". The issue was actually a cracked vacuum T beneath the throttle body, along with the MAF. So with a NEW "not Remanufactured" MAF censor and a vacuum line / T connector I am up to 25.23 MPG. I divided miles driven between fill-ups "using the trip-odometer" by number of gallons used.

All said and done I have replaced 2 Oxygen censors $125 each, 1 MAF censor "twice" $235 for the new one, 5 spark plugs $15, 1 air filter $14, some new vacuum lines and a plastic T connector $150, and 1 PCV system cleaning $350.

I now have no check engine light and enjoy roughly 378 miles travelled to the 15.03 gallons used. When I had previously gotten about 300 miles to a tank! It has been about a week and some 400 miles driven since the repairs and all is well. Ps. I do 75 to 80 mph highway and am trying to tame my heavy foot.
$350 PCV cleaning! I put all new PCV system parts in for $155 I think it was after the FCP Groton 10% discount.
 
  #51  
Old 07-28-2011, 10:04 AM
Member
Join Date: May 2008
Posts: 98
Default

Originally Posted by boldtu View Post
"Stage zero was performed on the car before we got it in 2009"


Chet
What is Stage Zero?
 
  #52  
Old 07-28-2011, 12:37 PM
rspi's Avatar
Administrator
Join Date: Mar 2009
Location: Albuquerque, NM
Posts: 15,762
Default

When you do all the service and maintenance on a car. Everything on the maintenance chart. Replace plugs, wires, distributer cap, rotor, brakes, rotors, PCV system, make sure your fuel injectors are clean and working properly, replace the timing belt, any worn suspension parts, etc.
 
  #53  
Old 07-28-2011, 07:28 PM
Member
Join Date: May 2008
Posts: 98
Default

Ah that makes sense. Sounds like a big bill too.
 
  #54  
Old 07-28-2011, 07:55 PM
rspi's Avatar
Administrator
Join Date: Mar 2009
Location: Albuquerque, NM
Posts: 15,762
Default

Not when you do the work yourself. The good thing about it is, once the car is at stage 0 it should be in great shape and go for a few years.
 

Last edited by rspi; 07-29-2011 at 02:33 PM. Reason: edit
  #55  
Old 07-29-2011, 09:14 AM
Member
Join Date: May 2008
Posts: 98
Default

Very true doing the work yourself saves a ton. And would last a while, but I was thinking if you had to do everything. Would probably be at least $800 in parts. Definitely worth it but hard on the pocket book. I when I think about it I have been slowly bringing my car to Stage 0, but probably by the time I get done I will have to start over. LOL
 
  #56  
Old 10-21-2011, 12:39 PM
Member
Join Date: Aug 2010
Posts: 86
Default

Originally Posted by rspi View Post
A lot of people do it but I use 93. The 87 is minimum.

Anywho, what is the condition of the car? When was the last time the car has been at stage 0?
I made the mistake of filling my first tank of gas with 87. The car would barely run. It was on the verge of stalling at every corner. The owner's manual states it will run on 87 or better yet on 91 octane. What I did not realize was that here in North Carolina all the gas is rated at the pump as AKI (anti knock index) plus 2. If you live in a state where the gas is rated 85-87-91, use 87 or 91. If your state lists the gas as 87-89-93 then use 89 or 93.
 
  #57  
Old 10-21-2011, 01:51 PM
rspi's Avatar
Administrator
Join Date: Mar 2009
Location: Albuquerque, NM
Posts: 15,762
Default

Most of the people I know use 87. I have done it a few times with no problems. The long term effect is what gets you. I have heard that it will cause carbon build up, knock sensor problems, and a few other effects.
 
  #58  
Old 11-03-2011, 11:49 AM
Junior Member
Join Date: Nov 2011
Posts: 5
Default

I use 87 octane and have for ten years in my 850 wagon, almost 30 mpg on highway.
 
  #59  
Old 11-10-2011, 12:37 PM
rspi's Avatar
Administrator
Join Date: Mar 2009
Location: Albuquerque, NM
Posts: 15,762
Default

I took a short trip yesterday and Tuesday and checked my highway mileage. I was a little surprised in the differences but this is what I came up with:

* At 55 mph, I was getting 33 mpg.
* At 60 mph, I was getting 30 mpg.
* At 70 mph, I was getting 27 mpg.
* At 75 mph, I get 24 to 25 mpg.

I ran each test for about 60 miles. Most of the road was flat. I think it would drop more the faster I went, like 80 would likely result in 20 to 22 mpg. Wish this car had an overdrive like the rwd cars have.
 
  #60  
Old 11-10-2011, 09:09 PM
Senior Member
Join Date: Nov 2011
Posts: 832
Default

clean your mass airflow sensor, use sea foam through your gas tank to remove carbon and check you tire pressure.a tune up will be a wise idea too.l changed my spark plugs using original volvo spark,rotor, and plug wires.used seafoam in my gas tank and l am getting up to 35 miles to a gallon under normal driving without turbo boast.try that.
 

Thread Tools
Search this Thread
Quick Reply: 850 Poor gas mileage - Tips to improve mpg...


Advertising
Featured Sponsors
Vendor Directory

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.