Mke:
Check the voltage at your oxygen sensor. With =
the wire
disconnected, engine running, I think it was supposed to put out =
.3-.5
volts aprox and when I checked mine it was reading .05 volts. =
It was
sending a message to the brain, begging it to enrichen the =
mixture.
The brain was complying, my air/fuel ratio was 9-10 instead of 14.7, my =
gas
milleage was down to 9 miles per gallon. After replacing the =
oxygen sensor
my gas milleage returned to it's usual miserable 14-15 miles per =
gallon.
It was an easy fix.
John
nal Message -----
Sent: Tuesday, May 08, 2001 =
7:58 PM
Subject: Running rich
My '84 GL =
is running
very rich. Mileage is 10 mpg at best. Blows thick =
black smoke
when loaded (i.e. under acceleration). Down on power in general. =
Idle speed is eratic but does not stall (yet?). Been =
driving
her daily
under these conditions for months.
Things I've done: =
Checked/adjusted ignition timing. Was retarded. Now =
correct
(at least
close). Made no difference.
Measured fuel =
pressure:
36 psi at idle with vacuum connected. 42 psi (at
any =
engine
speed) with vacuum line disconnected. If increase engine speed =
(with
vac. connected), fuel pressure decreases (yes, DECREASES) to about 32 =
psi.
Swapped out the air flow meter for another (used but serviceable) =
one.
No
significant change in behavior.
Examined the spark =
plugs.
All four were equally black and sooty.
I also cleaned (with
electrical contact cleaner and, in case of ground
connections, =
emery
cloth) and exercised all of the connections I could find
on the =
engine
management wiring harness.
I plan to measure the Temp. II sensor
resistance tomorrow.
An observation: I noticed that the =
position of
the AFM wiper is about 20 or
25% "open" with the engine idling. =
This
seemed surprisingly high to me, but
I have no reference. =
Could be
normal. Anyone have any input? I also
adjusted the CO
adjustment screw (under the plug on the AFM housing) and this
had =
no real
effect on the position of the AFM wiper. Had a small effect on =
the
quality of the idle.
I did a mechanical rebuild on this engine =
two
years ago (did not do anything
to the fuel injection/engine =
management
system). It ran fine and gave me 19+
mpg overall fuel =
mileage until
this problem cropped up a couple months ago.
Thanks for any
suggestions.
Mike
I know that there's probably been =
several
discussions in past on this
subject, but I am new to this list and =
I
haven't figured out how to search
the archives by subject. =
Maybe
someone can help this non-savy computer user
in this respect.