Car is 1981 240 GL B21F non-turbo red cap distributor with K-jet

Here are steps I've taken thus far:

1. Replaced leaking fuel pump and check valve
2. Tested O2 sensor in-line which fluctuates from .3-.59v at idle
3. Checked cold start injector and found no leakage
4. All new vacuum hoses and clean intake, PCV, flame trap etc.
5. CPR resistance tests good
6. New air filter
7. In-tank fuel pump running
8. No dragging calipers, bad bearings etc.

It has 155K miles and the original catalytic converter.

To be this severe, I'm thinking the cat is plugged and/or the O2
sensor is bad.

Appreciate any and all advice - can't afford to drive it!

Andy --

Any chance someone is using your car as a midnight gas station? Do you have a locking gas cap?

michael

I can understand (given the gross disparity of my MPG situation) why this has been suggested, but the car is garaged and the gas has not been siphoned.

Still in search of answers!

Thanks,

Andy --

With the gas mileage being half of what it should be, you should be able to see black smoke boiling out of your tailpipe just looking in your rearview mirror. Is the back of the car all sooty?
How sooty is your exhaust pipe?
Trying to figure out whether you are burning Rich or leaking it somewhere.
How is your acceleration? Normal?
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me

Maybe another clue: the new main fuel pump is really loud at all speeds.

Will pull the plugs and check for rich condition.

How to test for leaking injectors?

Thanks again,

Andy --

with all the effort and expense in cleaning the injectors, and, considering the mileage, i'd replace them. 100k is about their limit. to pay to have them cleaned only to find out they're worn out just adds to the exspense. good luck, chuck.

In-tank pump is running, but did you check to make sure that the hose between the pump and the fuel line is attached? (i.e. running does not mean it is pushing gas out of the tank.)

Yes - I pulled the cover off in the trunk and inspected the line where it hooks up to the in-tank pump. Both lines look OK.

Thanks,

Andy --

Perhaps I'm out of my league here, but did you check the fuel pressure regulator? (Read the FAQ on the FPR). If you have not already done so, make sure that the vacumn line between the FPR and the intake is good (not cracked and not obstructed.) Also make sure that the nipple it attaches to is not obstructed.)

Make sure you change your oil frequently if you are running this rich.

It could also be a bad ecu.

Good luck. This type can be frustrating.

fyi-this is a kjet car and not lh. stricly mechanical injection, much like a diesel. the faqs don't apply. off i go, chuck.

leaking injectors, control pressure to low when warm, co adjusted too high, weak coil and/or other ignition parts and, maybe, your odometer is somehow running too fast. good luck, chuck.

Correct me if I'm wrong Chuck, but wouldn't the odometer running fast cause his gas mileage checks to be higher then they really are?
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If you listen to the radio in Portland, OR, you may know me as "Portland's Favorite Soul Brother!"

ya caught me-it would be wonderful mileage if what i said was true. either way, the odometer is a long shot. thanks, chuck.

Yes, you are correct. A fast odometer would actually show better MPG than is true. Actually if the odometer were running too slow, it would make the MPG appear worse.

But he has a good point. People forget that the odometer is a fallible gauge just like anything else. However, to cause a 50%+ variance, you'd think the guy would have noticed the problem on out of town trips. Still, it's worth checking out (and easy enough to do) to rule out the possibility that a bad odometer is throwing his MPG calculations way off.

How is your tire pressure? That alone could explain 3-5 MPG of it. And when was your last replacement of plugs/wires/cap/rotor? Are you carrying any unnecessary loads? Are you heavy on the pedal? I find that just the basics make a big difference in mileage.

In addition to all of the other good suggestions, it might be time for an injector pressure flush and new seals.

Or maybe has teenagers---

I assume you are using the gas statiion pump to measure fuel used. If the engine were running that rich I would think there would be black smoke out the exhaust. How do the spark plugs look?

I had the same problem, I stopped shifting up at 5,500 RPM and that seemed to solve it.
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Drive it like you hate it