how to tell if M103 EHA leaks (91 300SE) - PeachParts Mercedes-Benz Forum

sixto · #1 05-17-2002, 08:49 PM

I've read about EHA leaks. I checked mine today in the process of investigating a mildly rough idle. It was clean and dry in place. As I loosened the Torx head screws, fuel started to leak from the EHA/distributor interface.

There's a flat head screw on the hidden side of the EHA that I hessitate to touch.

Is there anything I can do that will suggest that it's a good or bad EHA?

Are new o-rings in order? The ones there now are green.

Thanks,
Sixto
91 300SE
87 300SDL
81 300SD

Gilly · #2 05-17-2002, 08:52 PM

I would put it back on and reuse the seals. You can usually tell if you have a leaking EHA by the gas smell.
Don't mess with the screw inside there.
There is an amperage test which can help determine if the EHA is bad or not.
What's wrong with the car?
Gilly

sixto · #3 05-18-2002, 12:17 AM

Engine is fine except at idle at operating temp. Then it's just rough enough to be annoying but not rough enough to throw money at it. Been this way for the last 15K miles. Dealer did a tune up 10K miles ago and said there's dirt in the fuel distributor. Can it run so smoothly at anything but idle for this to be possible?

Oh, starting is a little difficult. Takes a while to catch, then stumbles for a few seconds before stabilizing. This happens at anything from hours to days after the last run. Warm restarts are usually not a problem.

While I was in the area, I checked the idle switch. Continuity at idle, open off idle.

Thanks,
Sixto
91 300SE
87 300SDL
81 300SD

Gilly · #4 05-18-2002, 08:52 PM

Without knowing more about the history of the car, i would suspect valve stem seals.
"Dirt in the fuel distributor", I like that, I'll keep that one in mind.
Gilly

burgeme · #5 05-20-2002, 02:25 PM

Sixto - I have the exact same problem as you describe. Mine is on a '89 300TE with only 99,000 miles on it. Been this way since we bought the car at 92K miles. I've tried just about everything to get rid of this "stumble" at start up and when stopped at a stop light. If I shift into Neutral or Park, the oil pressure gage needle goes up by 0.5 bar and this stumble disappears.

Things I've changed:
fuel filter
spark plugs
cap and rotor
cleaned out idle control valve
new OVP relay
put in Lubro/Moly Engine clean - w/o results

I can't say that I don't discount that the valve stem seals are bad but it doesn't smoke at start up and it has this stumble no matter when I start the car. Even if I shut it off and start right away it stumbles for around 2-3 seconds before starting and then once started stumbles another 1-2 seconds before the oil pressure is at 3 bar.

It sounds to me like something that goes to the EZL - either it wouldn't do the same thing when in Neutral or Park.

Now, there was some reference to a screw on the back of the EHA - knowing me, I probably would have turned this screw a little. What does it do and could this be my whole problem?

My independent told me that I needed a whole new fuel distributor (to teh tune of $800) because it was leaking. That's when I started digging myself.

Any help would greatly be appreciated.
Mike
'89 300TE 99K miles
'87 190D 191K miles
'85 190D 2.2L 5-speed 228K miles

JDUB · #6 05-21-2002, 12:16 AM

Burgeme, I would try new spark plug wires. My 103 developed a slight miss at idle. Anything above idle is smooth. I couldn't find a vacuum leak. However I know my valve seals are bad. When I stomp on it getting on the highway I sometimes leave a smoke screen bu not all the time. It never smokes at idle or at least not noticeably. A few of my spark plugs were dark and beginning to foul.