I am about to expose my ignorance :-) But what's an EHA (what do the letters EHA stand for). Where does it sit/where is it located? What does it do? Why does it leak? How does the leak affect cold idle? If it leaks fuel, isn't there danger of an underhood fire? I have seen the EHA mentioned in posts mostly dealing with rough idle, either cold or warm, and I've always wondered what the EHA is/does.

Also, is there a device that controls the timing and the pressure of fuel as it comes from the fuel pump and then shoots through the injectors? In other others, in a fuel injected car, what is the equivalent of the carb?

In my 1991 420SEL there is a large, round metal dome-like structure. It sits underneath the air cleaner housing. on the back of the engine, towards the firewall. Brass lines come out of this device and lead to each individual injector. I used to own a 1984 300SD and a 1967 250SE and neither one had a similar device. I look forward to your responses.

PS I did a search under EHA and mostly what I found were people writing about problems with the EHA, but I couldn't find answers to my questions above.

Thanks
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Current Benzes

1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"

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Not in this weather!

Read the excellent article in this site's D.I.Y. section:
http://www.peachparts.com/Wikka/EngineControls

He describes the operation of the EHA (electro-hydraulic actuator ) as well as the other fuel injection components. The article is mainly about newer vehicles but is good reading.

Thanks Steve!

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VR
1967 250SL