acceleration problem 1992 300E - PeachParts Mercedes-Benz Forum

#1 08-12-2003, 10:16 AM

I recently aquired a 1992 300E with 50,000 original miles from a family friend. The car ran really well for a while and then I ran into this persistent problem.

The car will be running smooth and all of a sudden I will feel a flat spot, sometimes I can accelerate through it and sometimes it's like there is no power at all. This seems to happen most often while driving in town (stop and go traffic) although it has also happened on the highway. I have had to press the accelerator 3-4-5 times until I finally get a response, it will run smoothly for a while and then act up again.

I have replaced: fuel injectors, fuel pump, filter, spark plugs,wires, rotor, valve seals, head gasket, isolated and flushed the fuel system, even flushed the transmission. The car ran very well for a few thousand miles and now I'm having the same problems.

ctaylor738 · #2 08-12-2003, 11:19 AM

This is agonizingly familiar - runs poorly but only intermittently. And the problem only appears when you are driving the car. And it gets better for a while after you replace something.

Other than sympathy, I can offer three low-cost suggestions.

- Spend $18 on the EHA test harness (PN 102-589-04-63-00) and connect it to some long leads to your multi-meter so that you can monitor the current readings while driving. You can verify that the readings are in spec, and observe differences when the car acts up. That may provide a clue to the problem and would at least eliminate mixture correction as a problem.

- Replace all the rubber vacuum connectors

- Run a couple of cans of Techron the system in the gas

haasman · #3 08-12-2003, 12:40 PM

bcbehan

A car of this age has very low miles. It makes me wonder if there isn't condensation/water in the fuel tank? Does this happen right after taking a turn?

You might want to try also adding dry gas or equivalent to get rid of moisture in your fuel.

You might want to also pull your fuel pump relay and look for corrosion on the contacts.

Keep us posted,

Haasman

yal · #4 08-12-2003, 01:12 PM

Quote:

Originally posted by ctaylor738

- Spend $18 on the EHA test harness (PN 102-589-04-63-00) and connect it to some long leads to your multi-meter so that you can monitor the current readings while driving. You can verify that the readings are in spec, and observe differences when the car acts up. That may provide a clue to the problem and would at least eliminate mixture correction as a problem.

Chuck: Could you tell me where you got the harness for $18?

ctaylor738 · #5 08-12-2003, 02:57 PM

It was actually $17 plus tax.

American Service Center, Arlington VA (dealer)

703 284 2450

Ask for Cesar

yal · #6 08-12-2003, 03:21 PM

Thanks, i'll give them a call.

d2bernhard · #7 08-12-2003, 07:48 PM

I gotta agree with Techron. Mine was diaged at the dealer with bad Fuel Distributor. Car ran terribly. I actually bought part ($1100.00) and was ready to install. Did one last double blast of Techron concentrate. Car started running fine and is now 9 months fine.

-fad · #8 08-13-2003, 03:08 PM

though probably not the primary cause of fault condition...

suggest removing air cleaner and cleaning-lubing the many accel linkage pivot points...include lubing accel pedal pivot assembly inside the driver's foot well>>> there may be a binding point(s) that can be freed with cleaning and lube

I've just done this on my '92 300e 2.6 and this maintence improved accel input (feel) tremendously

hope this helps and let us know what turns out
-fad

MARIO FARIAS · #9 08-17-2003, 12:17 AM

Thanks for your hint.

Chuck, Please, tell us if this EHA test harness (PN 102-589-04-63-00) may be used in the 300E and 190E, both 1988.

Thanks

Mario farias
laprefar@cantv.net

ctaylor738 · #10 08-17-2003, 09:16 PM

I think so. You should pull the air cleaner off the 190 and look at the connector, though.