re. factory instrumentation accuracy & mpg

Phil Rose pjrose at
Sun Jan 26 16:51:17 EST 2003

At 1:10 PM -0500 1/26/03, Brett Dikeman wrote:
>At 12:24 PM -0500 1/26/03, ben swann wrote:
>>Yes - peeve # 2 on the new aquisition of the '91 200 20v tq avant.  Has
>>SJM chip with 2.5 bar pressure transducer AFAIK.  Gas mileage abysmal
>>on the way home - 20MPG and no I was not easy on the gas and probably
>>averageing over 70.  My '87 5000 tq would get an easy 28 mpg under the
>>same conditions.  I thought Motronic was supposed to be superior at
>>engine management, including economy, over CIS (CIS/motronic).
>>What's up with that?

Ben, were you referring to mileage from the on-board computer--or actual
fill-ups? If the former, don't forget the error in computed MPG may be
pretty large (mine was at least 10% low) unless the fuel-consumption factor
is corrected (this is done by an IC adjustment, and I believe my write-up
about this can be found on Chris Miller's web site.) If you measured by
odometer and pumped amount, then I dunno.

I agree that 20 MPG sounds rather low--unless your foot was really into it
a lot. In my '91 200q, good gas mileage requires an extremely steady
throttle (irrespective of speed it seems). With very steady cruising I'll
routinely get 28 MPG even at 80 MPH; however with a lot of passing, hills,
etc., could easily drop to low 20s.


Phil Rose
'91 200q lago blue				Rochester, NY USA
'91 200q tornado red				mailto:pjrose at

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