300E irritable running - PeachParts Mercedes-Benz Forum

TCCBass · #1 08-01-2002, 12:32 PM

I've searched through the archives and not had much luck deciding on which part to replace first...

'92 300E. Runs flawlessly with A/C off. When A/C is on and car is cool (been sitting) it has no problem with acceleration. When it gets warm it gets sluggish and won't pull out of intersections without trying to die. It won't ever totally stall, but I have to EASE on the gas until it gains momentum. On the highway it will be sluggish, then all of a sudden take off.

My thoughts are:
O2 sensor as my fuel mileage is bad...130K and it's the original.
I'm leaning toward this as I am SURE it needs to be replaced.

OVP...the fuse isn't blown.

MAS...not sure how to check that.

Fuel Pump Relay...the fuel pumps don't seem to be cutting out.

The car just had a new fuel filter installed, and it seems to have gotten worse since then. When I run Redline or Techron cleaner through it, the stalling seems to be less on THAT tank but come back the next tank.

I appreciate ANY input and possible solutions. I know this is a popular subject.

pmizell · #2 08-01-2002, 12:50 PM

If your OVP has a single 10amp fuse then you probably have the notoriously faulty Siemens/Austria OVP p/n 201 540 38 45. The fuse can still be intact, but OVP bad. The new ones have 2 10amp fuses on top. This is where I'd start.

You might also want to check the voltage regulator attached to the underside of your alternator by 2 phillips screws. Pull it out and check the spring loaded brushes. If they're short and worn, then replace it. $10 for a generic here on Fastlane.

Good luck!

TCCBass · #3 08-01-2002, 05:07 PM

Paul,

Thank you for the response.

I'm going to start with the OVP and also the Oxygen sensor. I'm HOPING it's not the converter as I've noticed a foul smell twice this week after it's parked. Maybe the O2 would make it do that (I can always hope).

I guess I have decided to keep the gas car and attempt to sell the diesel. It is almost showroom in appearance and running condition. Maybe there will be a market for it.

mushedroom · #4 10-07-2002, 06:06 PM

does this go the same for a 1992 300ce?
i'm experiencing the same...
really horrible gas mileage...
and sluggish almost stall feeling performance on some take offs...

help.

TCCBass · #5 10-07-2002, 06:31 PM

I was just about to ask some more questions on this...thank you for beating me to it!

I put 2 bottles of Techron cleaner in on Friday and have been driving the car in 3rd gear a lot to clean.

The hesitation is GREATLY reduced. However, I can tell the converter is working overtime and the car is running REAL rich. It runs GREAT when cold but gets sluggish. If I floor the car (against the switch) the car just flies...at the expense of fuel mileage (I'm getting about 10-12 in town).

Does this signify:

Weak injectors?
Duty Cycle off?
EHA Valve bad (no fuel smell from engine)?

I have replaced 02, temp sensors, fuel filter, etc.

I'm going to attempt to check duty cycle this evening. I have no idea how to adjust it...but perhaps I'll figure out.

At least there is some sign of hope......

mushedroom · #6 10-07-2002, 07:03 PM

my car has always ran extremely rich...
to the point where i can't stand behind it for too long cause the fumes make me so so lightheaded....
is this normal?

#7 10-07-2002, 10:10 PM

Paul,

Which OVP's have 2 10amp fuses on them? I have the updated version and it only has one fuse on the top.

Dale

pmizell · #8 10-07-2002, 11:31 PM

Jet:

I guess it depends on your make and year. The updated OVP for my '91 300E has 2 red 10 amp fuses on top, with a clear red plastic flip top covering them.

I don't have the p/n available but can get it if you need it.

#9 10-07-2002, 11:48 PM

My mistake Paul, I have a 95 E320 and the discussion here is on earlier models. I'll have to blame it on too much crack as a kid. Crack kills you know!!