G'day

I have a small missfire/(surging probably caused by the miss) at light throttle at most speeds. I feel it especially at motorway speeds of 60mph etc.
Under full or heavy throttle its as smooth as a babies skin.

I have replaced the fuel filter today but that made no diff...I'm a new owner of Mercedes and am comfortable with mechanical repairs.

Any advice?

1989 300E
170,000km
Full service history


Thanx in advance

Maybe a vacuum leak?

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95 E320 Cabriolet, 159K

I think you've answered your own question!:p

Gilly

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HAHAHA Gilly :p

What it turned out to be was the ERA or ERG or whatever you call it. I changed it and WHAMOO the car is a completely different beast!!!
What was actually happening was it was starving for fuel which made it feel like a miss. What it was infact was a surge caused by the starvation. Apparently this Valve thingy makes it run lean if its not working.

Now it goes like a cut cat MEOW!!!

Cheers

That's great. Must have been the eGR valve-Exhaust Gas Recirculation, sounds plausible.

Gilly

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Whoops...maybe I'm calling it the wrong thing.
Its a black plastic covered metal thingy that bolts to the side of the throttle body. It has a plug that plugs onto it. It has fuel passing through it too.


Clear as mud?

EHA -- electrohydraulic actuator, controls fuel mixture via the O2 sensor. Bad one will cause mixture problems, in your case lean running at light throttle.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

hmmm - wonder if this is whats wrong with mine


after a long-ish run at high speed (100mph) then stop at traffic, theres sometimes a slight misfire. it gets wrse if i try to hold the revs at 2000 rpm (neutral) - once driving, it seems fine - i get 20 - 21 mpg (UK) (24 / 25mpg US) on 97 RON (88 - 90 MON)

oce got 29mpg (US) on a long [driving-like-an-old-granny] run

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C140 420 CL
W114 280CE pimpmobile
W114 250/8 Hillclimber with M110 and bike carbs - got any hot cams?

An egr valve problem can be diagnosed in two stages.

I. Disconnect and plug the vacuum line to the egr valve. If the problem disappears, then you may have a vacuum problem.

II. I prefer to block off the egr passage with a piece of sheet steel. If the problem disappears, then the egr valve is somehow stuck open -- probably with deposits on the poppet valve. The egr valve would need to be replaced. Or again, there is a problem with the vacauum.

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95 E320 Cabriolet, 159K

A little unsure about the location of the EGR valve. On my 126 380se is it the thermostat looking thing with a clear pipe with red stripe that is just on top of the exhaust manifold. I was doing a little inspection and realized that the small pipe connected to it is not connected to anything else. Where does the pipe run to if that is the EGR valve??

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**A few Hondas etc... etc... Not Worth Mentioning**
83 Euro W126 380 sel Money Pit (Sold)
91 W124 300e 2.6. (Sold) 3.0 Motor is Much better!!
93 BMW E34 Touring Wagon (Sold) Sweet Car!!
91 300e (Just 200k with Ease.)Best car ever ???(Sold)
90 420sel (Black with Tan Interior) Best car ever!!!!!!!