expat
New Member
I have a '94 C250 4-door diesel non-turbo (W202), automatic transmission. I think I have a fuel delivery problem, or possibly some kind of vacuum problem, and hoping you wiser MB hands can help me with the diagnosis.
I bought the car with 159k miles and now have about 175k miles (in the last 10 months). Initially the car ran like a top but then about 3 months ago it started having intermittent "surging" problems.
Sometimes it runs like a top, sometimes not. Sometimes the problem stays for a week and then disappears for two weeks, and sometimes it is here one day, gone the next, and back again later that afternoon. I have not been able to find a pattern to the problem's comings and goings.
To me it seems like a fuel delivery problem but I'd think the fuel pump either pumps or it doesn't. Ditto with the injector pump.
What is happening is that the car surges while driving (when not running like a top). Sometimes you start the car and it drives fine for awhile and then starts some "light" surging. Other times you press the gas pedal down and nothing happens, absolutely nothing. Then you press it again, and again, and again, and finally the engine revs and the car takes off like a rabbit, like it has found a new lower gear, and zooms along so quickly--like a runaway train--that you have to back off on the accelerator (and possibly start the process over again).
Sometimes on the highway I'm doing good to make 100k-120k. A slight uphill grade brings the speed down as there is no reserve power. You may or may not be able to feel the car is surging in this situation. Other times, when everything seems to be working correctly, cruising at 120k with reserve power under foot is just as it should be. Since the car does not have cruise control it will easily creep up to 130k-140k if I'm not paying attention.
But then then that evening, or the next day, or the next week, the surging problem returns.
Oh, if the problem is especially bad, the car won't shift easily from 1st to 2nd. It shifts out of 1st, then there is a pause as the engine revs up for a second or two, and then the transmission shifts to 2nd, the rpms drop down to normal and we continue surging along our merry way.
So any suggestions -- fuel supply?, vacuum?, something else entirely? Your replies are appreciated!
I bought the car with 159k miles and now have about 175k miles (in the last 10 months). Initially the car ran like a top but then about 3 months ago it started having intermittent "surging" problems.
Sometimes it runs like a top, sometimes not. Sometimes the problem stays for a week and then disappears for two weeks, and sometimes it is here one day, gone the next, and back again later that afternoon. I have not been able to find a pattern to the problem's comings and goings.
To me it seems like a fuel delivery problem but I'd think the fuel pump either pumps or it doesn't. Ditto with the injector pump.
What is happening is that the car surges while driving (when not running like a top). Sometimes you start the car and it drives fine for awhile and then starts some "light" surging. Other times you press the gas pedal down and nothing happens, absolutely nothing. Then you press it again, and again, and again, and finally the engine revs and the car takes off like a rabbit, like it has found a new lower gear, and zooms along so quickly--like a runaway train--that you have to back off on the accelerator (and possibly start the process over again).
Sometimes on the highway I'm doing good to make 100k-120k. A slight uphill grade brings the speed down as there is no reserve power. You may or may not be able to feel the car is surging in this situation. Other times, when everything seems to be working correctly, cruising at 120k with reserve power under foot is just as it should be. Since the car does not have cruise control it will easily creep up to 130k-140k if I'm not paying attention.
But then then that evening, or the next day, or the next week, the surging problem returns.
Oh, if the problem is especially bad, the car won't shift easily from 1st to 2nd. It shifts out of 1st, then there is a pause as the engine revs up for a second or two, and then the transmission shifts to 2nd, the rpms drop down to normal and we continue surging along our merry way.
So any suggestions -- fuel supply?, vacuum?, something else entirely? Your replies are appreciated!
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