help chasing down poor fuel economy

[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?

 

[Rusty]

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

 

[James Sweet]

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

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.

 

[John Roden]

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?

 

[Bob (archive)]

I have come to the conclusion thatr my 1983 245 b21ft gets pretty lousy mileage at about 16 to the us gallon.

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.

 

[Gary Heston]

John Roden wrote:

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?).

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.

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

 

[TWC]

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

 

[TWC]

my 88 240 with B200E ,CIS K jet , runs at 23mpg-24mpg.

Gary Heston ¼g¤J¡G

 

[James Sweet]

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.

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.

 

[John Roden]

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.

 

[James Sweet]

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.

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.

 

[John Roden]

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!