Re: Subject: 4k gas mileage

[Orin Eman <orin@wolfenet.com>]

> Andrew wrote:
> ---------------
> A few days ago I struck up a conversation w/a woman in a pre-'85 non-Q 4000
> that had 190K miles on it. I didn't find out if she'd had the car from new,
> but she'd had it a long time.

> At one point I asked about gas mileage. She said it used to get 38mpg on the
> road, but now it's down to 30. I didn't probe further, but I'm assuming that
> both figures were compiled over time, we're comparing apples w/apples, and
> just tuning it up doesn't restore the missing 8mpg. Of course, lowered
> mileage from an engine w/190K of wear and tear on it sounds plausible. Is
> the delta here about par for the course?
> ------------------------------
> I'm guessing this is the 4 cylinder engine; basically a VW.  I believe the
> only VW of this era to get 38 mpg was the diesel rabbit, a lighter car, BTW.
> Seems like her figure of 38 is inflated; 30 seems more like it, especially if
> just highway miles.  Could be that she's relying on a trip computer (if it has

On the contrary, 35mpg+ is easily achievable in early 80s 4ks.  I used
to average 35 in an 82.  No trip computer BTW.

Is that 38 figure for the diesel Rabbit the EPA figure?  If so,
remember, YMMV!

> one), and the computer is inaccurate.  Don't expect that high miles would
> lessen mileage significantly, if it's in tune and working in spec.

First thing to suspect is the O2 sensor.  Otherwise, lower compression
due to worn rings and/or valve could contribute given high miles.

Orin.