help chasing down poor fuel economy

  • Thread starter Thread starter John Roden
  • Start date Start date
J

John Roden

I have come to the conclusion thatr my 1983 245 b21ft gets pretty
lousy mileage at about 16 to the us gallon. Here's what I have done
so far:

new engine wiring harness
new plugs, cap and rotor
new catalytic conevrter
new 02 sensor
replaced all the vac lines
replaced vac delay valve

I tried spraying some wd 40 around the injectors to see it they were
leaking, I unplugged the cold start valve to see if was running all
the time. I have found the coolant temp sensor and idle air motor are
shot and have new on order, but I don't think this is the problem.

So... Maybe check the control pressure (really, I mean get it
checked) but I'm wondering if there are some other items I can check
myself before I take it to the shop?
 
How's the air filter, air mass meter and the oiltrap? Those are things I
look at when tracking down poor mileage on my B230FT.

cheers

RS
 
Rusty said:
How's the air filter, air mass meter and the oiltrap? Those are things I
look at when tracking down poor mileage on my B230FT.

cheers

RS
Click to expand...

Well there is no air mass meter or oil trap on a B21FT, but the air filter
is a good place to start, as well as cleaning off the airflow sensor plate,
be careful not to disturb it's alignment though.
 
Oops, forgot to list those items, I already did those a while back,
along with cleaning out the throttle body while I had the intake
manifold out. Maybe I should turn the screw and lean out the mixture
a tad?
 
John said:
I have come to the conclusion thatr my 1983 245 b21ft gets pretty
lousy mileage at about 16 to the us gallon.
Click to expand...


My '76 245 & '86 245 both got consistently lousy gas mileage in the
20-some years I drove them (possibly due to my heavy foot?).

Now if you mean it happened suddenly... then you may have some problem -
otherwise, it's normal for your driving habits.
 
John Roden wrote:
Click to expand...

Last time I checked, my 1972 145 B20F was getting around 12-13.5 MPG.
I'd be real happy if it went up to 16MPG.
My '76 245 & '86 245 both got consistently lousy gas mileage in the
20-some years I drove them (possibly due to my heavy foot?).
Click to expand...

My experience has been that this doesn't have a real bearing on mileage,
unless you're trying to emulate the _Fast and Furious_ twits with tire-
burning launches, redlining every gear, etc.

You'd have to get real numbers from a couple weeks of driving each way
to be sure, though.
Now if you mean it happened suddenly... then you may have some problem -
otherwise, it's normal for your driving habits.
Click to expand...

Yes, it could be a distributor being loose and rotating a bit; strange
how poor a B20F runs when the timing is off by five degrees. Then again,
I may need a new distributor; as long as I had the vac line disconnected,
engine ran smooth whether it was plugged or not; slip the hose on the
nipple, immediate bogging and timing shifted five degrees. Set it with
the hose connected, and she's running fine again.

Lots of fun to do this outside in 40F temperatures, BTW...


Gary
 
if its a K jet engine,there's a small hole behind the fuel
distributor,using a 3mm long hex. key can adjust the A/F ratio at all rpm
band ,turning clockwise to rich the mixture and counter clockwise to lean
the mixture.Each time turning this screw not more than 1/4 turn and
observe the CO ,I've install a A/F meter for monitoring and  notice the
car perform difference. I adjust this screw on my 240 and Golf 16v to
improve the fuel economy and accerelation. Its noticeably
Besides,check the engine timing as well.

John Roden ¼g¤J¡G
 
my 88 240 with B200E ,CIS K jet , runs at 23mpg-24mpg.

Gary Heston ¼g¤J¡G
 
Bob said:
My '76 245 & '86 245 both got consistently lousy gas mileage in the
20-some years I drove them (possibly due to my heavy foot?).

Now if you mean it happened suddenly... then you may have some problem -
otherwise, it's normal for your driving habits.
Click to expand...


I managed to get as low as 15 mpg once on my 240T, but it was right after I
cranked the boost up to 16 psi, and it was all city driving with lots of
very hard acceleration. That car should get at least 22 mpg on the highway,
25 if you drive it somewhat gently. Around town I average 17-19.
 
OK, thanks. I have to find a 3mm that is a lot longer than the only
one I have, hopefully that will help matters. I bought this thing
because I wanted better fuel economy than my 4 wheel drive van, but it
is the same or worse and doesn't have the room and is kind of crummy
in the snow, even with 4 Nokian tires. At least it has given me the
chance to sharpen my mechanical and electrical skills and maybe it's
safer in a crash.
 
John Roden said:
OK, thanks. I have to find a 3mm that is a lot longer than the only
one I have, hopefully that will help matters. I bought this thing
because I wanted better fuel economy than my 4 wheel drive van, but it
is the same or worse and doesn't have the room and is kind of crummy
in the snow, even with 4 Nokian tires. At least it has given me the
chance to sharpen my mechanical and electrical skills and maybe it's
safer in a crash.
Click to expand...

Very much so, and if well taken care of it should last a lot longer, but the
real joy with these cars is a nice day on a winding road with a good set of
sport tires. When set up properly you get the utility of a wagon, the
handling of a sports car, combined with the safety, comfort and longevity
that made Volvo famous, as well as they seem to be invisible to cops.
 
Boy, the 3mm wrench needed to adjust the fuel flow must need to be
very long, I'm not having a great deal of luck locating one out here
in the boonies, I think one of the "t-handle" type is required.

I still have some more chassis work to do before zipping down any
winding roads!
 
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