need advise - PeachParts Mercedes-Benz Forum

lukemus53 · #1 01-10-2003, 09:16 AM

my '84 300d is starting to miss when under a hard pull. Seems to be worst when cold. thanks for any help.

#2 01-10-2003, 02:14 PM

There are a lot of things that may cause this. Better start with the simpler screenings to see what shape the engine is in.
Might run a compression test. Take one and if any of the cylinders come up low, drip a little motor oil in there and retest. What I am thinking is the possiblilty of a burned or open valve. That brings up the next thing to check. The valves may need setting. A valve wears into the head and with enough wear will stay open. When was the last time your valves were set?
The other thing that is possible would be fuel delivery. That one is a little tougher. You may need to have the injectors checked for the spray pattern. Before doing that get some Diesel Purge and run that through the injectors. Quick and cheap way to see if anything improves.

kerry · #3 01-10-2003, 02:48 PM

I'd change both fuel filters before doing anything more complex than that.

engatwork · #4 01-10-2003, 04:00 PM

I agree with Kerry - change both fuel filter first.

P.E.Haiges · #5 01-10-2003, 05:34 PM

Lukemus,

Does the car missfire erratically or just lose power? Loss of power under full power is usually an indication of a plugged fuel filter but it usually doesn't make the engine missfire like a gasoline engine does. Replace the primary first and if that doesn't help replace the secondary filter.

Erratic engine performance can be many different things.

Let us know what you find.

P E H

lukemus53 · #6 01-12-2003, 01:45 PM

thanks for the response.changed both fuel filters yesterday and that seemed to do the trick.started first time this morning at 27 degrees and didn't miss a beat as i hit the road.you fellows are great!