Driving on the highway one gas tank hits half point the car starts losing pick up. Once I top the tank off the power is back to normal. When I started the trip it was happening when my tank was quarter full, seems to be getting
worse as I keep going. Im on a family road trip so I really don't have time to stop and experiment much. I'd like any possible solutions.

 

Could your supply & return fuel lines be switched in the engine comp ??

The return line extends approx 1/2 way within the tank and could be related. The two lines are top of the driverside fender, routed together.
Long shot, but less messy than pulling the tank/ tank strainer.

Good Luck,
Gary

 

I'm going to check the strainer finally. How do I get to it?

 

Have you cleaned the strainer yet?

I've had this problem with both my '82 & '85 300D's.
Apparently, these cars are susceptible to microbial growth (slime)
in the tank. Maybe a little moisture in there encourages growth.

I've never had to remove the strainer, though. From what I've been told,
it's sort of like a sock that gets slimed up. As the fuel level decreases,
the strainer has more tendency to block the standpipe outlet. (I think
there is a standpipe.) Mine got worse over time too.

You need to start adding some sort of anti-microbial substance to your
tank on a regular basis. This will greatly help the problem over time.
I just started to use a product called Bio-Kleen. I found it at Tractor
Supply & it seems to work well (so far).

Also, keep a close eye on your primary fuel filter as it will clog with the
slime & leave you high & dry on the road-side. I carry a spare in the trunk.

Hope this helps.
Bill

 

The fuel tank strainer is accessable from underneath, near the rear diff. Follow the fuel hose up to a bulkhead threaded fitting, this threads into the strainer, which threads into the fuel tank. There is a special short socket, like 42mm, but I did not have that. I almost could get large channel locks on it, but could not control them and did not wish to crank the jaws into the bottom of the tank. My tank would not drip fuel out of the tank strainer fitting due to the excessive blockage. Looked like asphalt completely covering the strainer.

I pulled the entire tank thru the trunk, just pull the carpet fasteners, carpet, four nuts, disconnect the filler tube, and carefully remove tank.

My 83 300D was a garage find, sat for 4-5 years and water collected and rusted the bottom, which I comprimised upon reinstallation. I ended up replacing the tank with a pnp.

With the tank out you can do a better job in cleaning the tank and visually inspecting thru the sender opening.

Good Luck,

Gary

 

I've got an 82 240D, and it started doing the same thing a few months ago. It would lose power when the tank still showed half full. When I started calculating the fuel mileage, it turned out that the gauge was somehow getting stuck at about half full. The tank was dry, it took 13 gal to fill up.

We fill up every 300 miles now.

 

EBE,

The tank could not have been dry if it took 13 gals, I can not remember my 240 capacity, I know my 300D is 21 gals.

I am sure the 240's is much larger than the 13, more like 18+.

Was this in city, short drives ? If you wait an hour, overnight, the crude buildup on the tank strainer subsides and allows for a "clean" portion of the strainer to pass fuel. The strainer is 2" in height and the buildup starts at the bottom and procedes up until the entire length is blocked.

I would be looking to pull the strainer & clean. Additives help, but cleaning the strainer outside the tank, I have found, is best.
Good Luck

 

I can't remember putting more than 14 in, even when the gauge work properly. 13.5, 13.2, usually around that much fuel.

I did run completely dry on the Garden State Parkway a few years ago. It was late, I was 3 miles from completing a 400 mile trip, and I stretched it too thin. Parked on the side of the road, called the 800 number in the inside of the glove box lid, (it still worked!) and the tow truck brought me 3 or so gallons for free.....

After that I kept it above a 1/4 tank.

Regards,

Ed