I actually have the Mercedes EHA harness and have tried to figure out the readings on several occasions - not sure how to interpret these mA readings...

The EHA valve is brand new - well, within the past few months (old one was leaking). I am well aware of the problems with the reading the duty cycle (if you read through my previous posts you'll see numerous questions on this very topic - both here and on the SL forum). I also have a '91 300CE (M104) and it reads just the opposite (red and black leads have to be connected the other way to get the initial 70% reading - CONFUSING!).

Since I have no fuel pressure leakdown, as observed with my pressure gauge, I don't think my injectors (or even the gas cap) are the problem - right? I am maintaining above 3.0 bar pressure for hours after shutting off the car...

As far as vacuum leaks, it seems that this is effecting my idle and hence, both the duty cycle mixture readings and the EHA miliamp readings. I am thinking I need to get this idle evened out first...but I'm not sure? As far as that problem, in spraying carb cleaner around different areas, the idle noticeably changes when I spray around some of the injectors. I don't know if this is enough to cause all of my problems, but I don't see any other vacuum related issues. I am thinking I will replace the seals around the injectors, but I am a little confused as to what all I need to replace. I show o-rings, seals, and fuel injection insulators - do I replace all 3?

ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE