IML: Fuel Economy on EFI cars

["Dick Benjamin" <dickb@xxxxxxxxx>]

Bill,

I don't know who posted that note, but I do not recognize the advice or the
part name.

16MPG is at the low end of normal for mileage with around town driving - you
should do better on a trip, if your car is in a good state of tune.  Ours
gets around 18 in town driving, with fairly vigorous driving, using premium
gas (91-92 octane).   

Try this:  find a flat, level road that is straight for at least a mile or
two, switch your display to MPG readout, accelerate to 55 MPH before you
enter the "test area" and hold it there steady without wiggling your foot
(or else use the cruise control) and make two runs, one in each direction.
After the car reaches 55 mpg, it should hold pretty steady at around 27 to
28 MPG as an average on a flat road, if you have the right size tires on it
(205/70R15s).  

If you have larger tires, it will read lower (although you are actually
going faster than your speedometer indicates, so you are getting as good or
better fuel mileage, but the computer won't know it).  For instance, if you
have 215/70R15s, run it at 52.5 MPH indicated, and add 5% to your MPG
readout.

If it's lower than that, there are some things you can check, but don't
bother about it unless you know it's really below par.  The main rule with
these cars is "if it ain't broke, don't fix it"!

These are sort of in the order of difficulty and likelihood of helping:
.
#1 is to make sure your transmission is going into lockup at 44 or so MPH
(you should faintly feel a shift into what feels like a 4th gear, somewhere
in the mid 40s, at light throttle).

#2 is to make sure your initial timing is set at 12 BTC

#3 is to get a new air filter element if you cannot see sunlight clearly
through your old one

#4 is to make sure your tires are at 30 PSI or higher

#5 is to get a meter and check your EFI Coolant sensor readings (correct
values are on the IML site)

#6 is to perform the "runs with lid off" routine as given on the IML site
and visually check for plumbing problems - leaks in the HSA plumbing, and
that all 8 nozzles are spraying fuel.

#7 is to put in a new set of spark plugs, a new O2 sensor, new plug wires,
rotor and cap.

Dick Benjamin

P.S.  The method to switch to plain text was given here on the IML by some
other folks a couple of times in the last few days - you should be able to
find it by looking back over the weeks postings.

________________________________________
From: Bill Longest
Sent: Saturday, December 30, 2006 10:07 AM
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: Re: IML: part for 1983 EFI car

Dick,
Thank you for responding.  I will have someone that knows something about
computers look at my e-mail before I post anything else.  I have no idea how
to change it.  
I was reading  on the club website  under Fuel injection, "running rich"
that if you were cruising on the highway and floored the accelerator and
there was a hesitation that the "anti stall valve was bad'.  I was hoping
that this was something everyone knew but me. (ha). I attempted this and on
my 83 and it did hesitate and then ran poorly for the next few miles,
(hesitated at stop lights etc).  It had been running fine and is now ,but
,even after testing everything you had told me to in your last email, it
still is getting 16 mpg. I do not have a part number or even know what it
looks like. Thanks again.
Bill

Dick Benjamin <dickb@xxxxxxxxx> wrote:
Bill, can you tell us the part number? I don't find that part name in my
parts book, so perhaps it has another name?

By the way, you are posting in HTML also. Can you change to plain text for
us, please?

Dick Benjamin




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