Getting only 15-16 MPG combined driving...

Post by **E Showell** » 26 Sep 2014, 08:14

Bosch only on the MAF and 02 sensor. 02 sensor can usually be had on Amazon for <$100.

PCV system refresh has been extensively written up on this site with a very comprehensive guide having been posted -- at the moment, I forget who posted it, but he deserves great credit since it is a wonderful write up. The DIY job is a 3 wrencher out of five and you should leave the better part of a day for it -- figure six hours if you've never been in there before. You might do it in substantially less time, but if you block out the amount I suggest, you won't be unpleasantly surprised. My time estimate builds in for having to trot off to the local hardware store to pick up a tool or two mid-job. I found the toughest aspect of it was dealing with the intake manifold bolts. The lower ones only need to be loosened since there are slots in the manifold that they slip over on the bottom, but access to those bolts without some funky swivels and extensions is pretty tough and the visibility on the end one on the timing belt end of the engine is, let's just say "interesting."

This is not said to discourage you. It is doable if you can turn a screwdriver, but it is nowhere as easy as say, an ignition tune-up.

Post by **northernlights** » 26 Sep 2014, 08:31

TheLoneAviator wrote:2nd drive 2 miles
temp IN 620*F
Temp OUT 520*F
seems the outlet temp should be Higher shouldn't it?

The cat is a reactor, so the outlet temp should be higher than the inlet if it's working. That's why they put heat shields on them!

Also, 20" Hg is typical at idle for a car with reasonable cam timing. 10" Hg at idle with no leaks is lumpy cam territory. If you have a giant vacuum leak then someone might misdiagnose the MAF as being bad because so much air is getting in unmeasured that it looks like the MAF is dead.

I don't know if you have a means of doing this, but if you can check the short term and long term fuel trim. They will be +++ a bunch if you have a giant air leak.

smoggyama · Post by **smoggyama** » 09 Oct 2014, 13:06

Hi, I'm having the same problem. I have done everything save for taking it to the dealer. Did you ever solve the low mileage mystery? Thank you from SoCal.

TheLoneAviator · Post by **TheLoneAviator** » 12 Oct 2014, 11:40

I took it in for diagnostics to a non-dealer European Car guy that was willing to tell me what was wrong with it. He told me the PCV system needed replaced, the O2 sensor had no output, and the MAF sensor was not working. I have the PCV & the o2 sens but haven't had time to tear into the engine to make the repairs yet. I'll do the MAF last as it's easy on top. After I make the repairs and drive it I'll report back but it will likely be at least 4 weeks.

Post by **regent** » 13 Oct 2014, 10:51

TheLoneAviator wrote:...European Car guy ...told me ...the O2 sensor had no output, and the MAF sensor was not working...

And no codes? Hmm...

Post by **E Showell** » 13 Oct 2014, 11:49

I had a front O2 sensor do a slow fade on me without throwing any codes.

mika · Post by **mika** » 15 Oct 2014, 14:54

smoggyama wrote:Hi, I'm having the same problem. I have done everything save for taking it to the dealer. Did you ever solve the low mileage mystery? Thank you from SoCal.

I had similar issue. It ended up being e-brake pads seized onto a rear wheel hub. mpg was very low. I was thinking sensors all over. does it feel "heavy" , clear indicator that you need to take a look at drum brakes in back. especially in socal, where I had this issue, everything is so dried out and cracked because of the dust and heat with no rain

Post by **matthew1** » 15 Oct 2014, 14:59

E Showell wrote:I had a front O2 sensor do a slow fade on me without throwing any codes.

Me too.

Post by **E Showell** » 15 Oct 2014, 15:39

And when I say slow fade, I mean like 18-24 months.

moacyr · Post by **moacyr** » 17 Oct 2014, 08:46

I have a 1995 Volvo 850 NA with the same problem. Fuel consumption is high (around 11mpg in town), CEL came with P0172 (system too rich bank 1). Smell of unburnt gas from outside.

I recently changed that fuel hose from return line on the top of the engine, because the last one was twisted. I suspected that fuel was being burnt instead of returning. The new one just twisted again.

I guess we have the same problem as this one below:

http://www.justanswer.com/volvo/6yujs-p ... -mean.html

Didn't manage to look at it yet, but could be something clogged just before the fuel pressure regulator

Ideas?

Getting only 15-16 MPG combined driving...

Re: Getting only 15-16 MPG combined driving...