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Subaru Crew MPG-Real World Numbers

87 messages,  Last post on Jun 24, 2008 at 1:29 PM

You are in the Subaru Crew Forum.

What is this discussion about? Subaru, Fuel Efficiency (MPG), Truck, Sedan, Wagon, SUV

Your Community Leaders are ateixeira and rsholland.

Messages Page 9 of 9

#79 of 87 Increase of ~2.5 mpg by amsbear

Oct 15, 2007 (8:22 am)

Since replacing my Knock Sensor, I have seen a nice increase in MPG . It was throwing an intermittent CEL (P0325) that specified a Knock Sensor Circuit Malfunction and was able to replace it myself (with a few hiccups) and since then been rewarded with the following jump in MPG over the past two tankfulls.
 
Most recent MPG results.
25.925
25.684
22.684
23.170
24.430
22.689
22.814
23.060
 
Now those "hiccups" were due to me leaning into the engine bay a bit too hard while doing the sensor replacement .
 
#1 - I unseated the cruise control cable/linkage a bit which caused a P0507 Idle Control System RPM Higher Than Expected CEL. I started hunting down IAC issues until I noticed the problem and simply resnapped the cable back.
 
#2 - Cracked a vacuum line that operates the EGR, which led to it throwing the P0400 EGR Flow Malfunction. Fixed that with a new section of appropriated tubing.
 
Now I can take it in for inspection with my fingers crossed.
 
Alan
98 OBW Ltd - 139,500 miles

#80 of 87 Knock Sensor by masteryoda

Oct 18, 2007 (8:47 pm)

Hi Alan. I got a CEL light myself for the Knock Sensor on my 98 GT. Do you have instructions on how to change it?

#81 of 87 Re: Knock Sensor [masteryoda] by amsbear

Oct 19, 2007 (10:06 am)

Replying to: masteryoda (Oct 18, 2007 8:47 pm)
Recommended tools:
  Flashlight
  Socket wrench
  8" socket extension
  12mm socket
  Magnetic pickup tool
 
Finding the sensor was the first issue.
 
[copied from a Nabisco post]
The knock sensor is located on top of the block, above the #4 cylinder. It should be on the drivers side, left of the throttle body near the cable linkage if you are standing in front of the engine. There may be a EGR solenoid in the way, so you need to peer pass that to see it. It should be a black round thing with a 12mm bolt through the middle, connected by one wire, but with a white 2-pin connector.
 
Getting to it with hands and tools is the 2nd issue
From the drivers side -
With the socket on the extension, I seated it on the bolt, attached the wrench and backed it out. I had the magnetic pickup handy to get the bolt fully out. Put this aside as you will likely need it during the replacement, my part from the dealer did not come with a new bolt.
 
From the passenger side -
Pull the sensor out into the more open area on the left side of the throttle body. I pulled it through using where it connects to the harness.
There is not enough room on the right side to get both hands in to release the connector from the harness.
Unclip it from the harness and attach the new one onto the harness and thread the sensor back under the throttle body.
 
Back on the drivers side -
Again use the magnet tool to pull it into the generally area where it has to be remounted.
Put the bolt back through the center of the sensor and carefully guide it back down towards the engine block.
With just the extension and socket, attach to the bolt and "feel it" back into the bolt hole.
Turn it counter clockwise a bit just to be sure of alignment and that you will catch the threads correctly.
Attach the wrench and tighten it down, but not too tight. There are warnings that you can damage the sensor if you really overtighten it.
 
"Plug n Play" right?!?!
 
Clear your code(s) and start her up.
 
Good Luck!
 
Alan
98 OBW Ltd

#82 of 87 Re: Knock Sensor [masteryoda] by amsbear

Oct 19, 2007 (10:26 am)

Replying to: masteryoda (Oct 18, 2007 8:47 pm)
BTW, my dealer charged me $107 + tax. If you are not in a hurry, I am sure you can get a better price online.
 
I used a Subaru Bucks coupon so it was only $15 out of pocket.
 
Alan
98 OBW Ltd

#83 of 87 Re: Knock Sensor [amsbear] by dliboiron

Oct 21, 2007 (9:54 pm)

Replying to: amsbear (Oct 19, 2007 10:26 am)
Subaru bucks, how do you get those? Are they available in Canada?

#84 of 87 Re: Knock Sensor [dliboiron] by amsbear

Oct 22, 2007 (9:27 am)

Replying to: dliboiron (Oct 21, 2007 9:54 pm)
Chase offers a Subaru credit card where as you spend on the card, you accumulate points (3%). The dealers honor these for parts, service, and car purchases.
 
I'm not sure about the Canada availability. Take a look at the Chase credit card site for details.
 
Alan
98 OBW Ltd

#85 of 87 Mileage by stantont

Dec 30, 2007 (12:29 pm)

'08 OB XT turbo, MT5. First trip after breakin. Approx 2500 miles at start. 75-80 mph on cruise control. [Included about 50 miles of letting family try out the car in New Orleans; that particular tankful only came to 23 mpg(!).]
 
 TOTAL: 103.0 gallons for 2839 miles equals 27.56 mpg. Wouldn't be surprised to see it creep to 28+ by 20k miles.
 
MPG indicator is about 10-15 % low; it read 25.2 mpg for trip. At first I was pretty disappointed in "mileage" until I realized the trip MPG calculator was off.
 
Looks like the new EPA test routine (18 city, 24 highway, Hah!) is pretty hostile to the turbo. I routinely get 22-23 city, and the highway mileage speaks for itself.

#86 of 87 hyper-miling Forester by 10years

Jun 21, 2008 (8:26 am)

03 Forester, 4 EAT, 83 K miles.
 
Last year, June 2007, I'd been averaging about 25.5 mpg. But now I'm averaging a touch better than 28 mpg over the last three fill-ups. Although I'm not a hyper-miling purist, I've kinda of:
1. Inflated tires a couple pounds more than the door placard shows.
2. Slowed down to not exceed speed limits very much and mostly stay in the right lane.
3. Look far ahead to anticipate conditions to better to take advantage of coasting and light touch braking to minimize full dead stops and starts.
4. Go light on the accelerator.
 
On the downside my 26 mile compute time is extended about 5 minutes and the brakes have developed a light squeal.
 
        Have Fun,
        Ted

#87 of 87 Re: hyper-miling Forester [10years] by ateixeira

Jun 24, 2008 (1:29 pm)

Replying to: 10years (Jun 21, 2008 8:26 am)
The brakes probably do that because you rarely use them!

Messages Page 9 of 9

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