I have seen many posts of people complaining about a similiar problem as mine, but I have yet to find anyone that responds later solving this problem.

At highway speed I slowly loose power droping to 55 and below with the pedal floored. This happens when i get to a slightly uphill section of the highway. I assumed this is a gas supply problem so I proceded by replacing all ruber lines. Pulling out the strainer in the gas tank (which wasnt clogged at all). I blew out the two metal lines going back to the tank. I ofcourse changed the filters as well. And all was well for a couple of weeks.

Today I was down to a third of a tank and the problem came back. I pulled off the gas cap and thought i might have heard some suction (not sure). However the problem persisted as I drove without the gas cap. I went home and replaced the air filter (as I had bought a new one knowing mine was pretty clogged with oil). No change on the highway. I filled the gas tank full, hoping for added pressure. still no change. I went home switched my return and supply lines around. no change. I did notice that when i pulled the lines to swith them it was pouring out....thought the diesel would really fly out? This seems like it is really difficult to measure the injector pump or lift/primer pump (I think thats what it is) perforamnce. They are obviouly supplying diesel just not when I really need a lot on the hightway.

Like I said I have seen many post with duplicate problems..but no responces of what fixed your situation. Are all these cars in the junk yard? Please...Please...respond.

Thanks in advance,
Brent

It's just a clogged fuel filter again. Apparently, you have enough debris in you fuel tank that you clogged the filter again. I assume you changed both filters last time?

You can check the first (small) filter by blowing through it. If it's clogged, you can rinse it out and reuse it. If your performance returns you will know the secondary filter (spin on) is OK.

Sounds like changing the filters "fixed" it the first time. These old cars can have their fuel systems pretty gunked up, especially if it's been sitting a while. Algae is a big problem with some. It collects in the filters and plugs them up, producing the same symptoms you have.
Try changing one filter or the other to narrow it down, and look for black goo in the clear primary filter.

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'83 300D Turrrbo 295K miles

treating the tank with biocide usually will clean out the bacteria and let it run through the filters and burn off.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

It appears you were right, of course. I replaced the filter and all appears to be fine. I found a lot of rust in my filter. I'm surprised that all of a sudden so much rust is coming at once. What is the best way to take care of this rust. Hopefully a way without removing the tank (this sounds like a lot of work). Do I just need to keep changing filters (will the rust stop on its own)? I didn't see any black deposits in the filter or any other signs of algae when I prevously removed the strainer in the tank.
Thanks

How long did the car sit before you got it? If the tank was not full during it's idle period, chances are condensation caused the rust. If it did not sit, then you may have hit with bad/water contaminated fuel. An inspection of the tank would be a good idea to avoid the possibility of a rust through.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Hey Brent 888...I'm glad I read this post. I had the similar situation on my 83 240D and have been repeatedly changing filters. It did help but I'm now noticing rust accumulating in my primary filter. I'm waiting for the weather to get warmer and I will be pulling the tank for inspection. If the source of the "rust" is too bad, I'll change the tank completely. Thanks to the other guys that have offered some info.

I know, Jim's favorite pet peeve. But when are we going to quit calling the product we use for fuel, gas. Come on guys, this is the Diesel Forum. Gassers burn gas, diesels burn "fuel" or "diesel". It makes for a really bad day if you ever do a fill up with gas, so let us learn to avoid that word here on the Forum. Use the word "gas" around your diesel vehicle and someone will gas it up!

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

If your tank is rusty I would do the following.................

The 123 fuel tank is not difficult to remove. Remove fuel cap and seal around around tank neck. Remove first aid kit box, thus exposing the electrical connector for the sending unit. Disconnect.
Open the trunk lid. Remove the screws that hold the back panel, thus exposing the rear tank. You will see a gold colored bracket on each side of the tank. I think they are held with nuts. Loosen the nuts.
Crawl underneath the car, remove all hoses attached to tank. Have a catch pan ready. (It's a good idea to drive the car until the low fuel lamp is on, then drive it some more). Plug the lines as a precaution.
Tank will now slide out, have it professionally steam cleaned. Our NAPA here in Staunton has an excellent two part epoxy product called KREAM, made for the inside of fuel tanks.

I have personally experienced the same problem, but with a different solution. There was a bushing on the throttle linkage that was prone to fail after a few hundred thousand miles. The linkage would "bind", thus causing the pedal to "bind" etc. The bushing was a 103 part number, it has been too many years since I sold one to recall the number.
Alan

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DO IT RIGHT THE FIRST TIME, DON'T BE A HACK
Political Correctness is NOT part of my vocabulary
and finally FIGHT CRIME...SHOOT BACK

'82 240D Stick
'85 300D Auto
Drove my first MB at age 16 1960 300SL W190