PeachParts Mercedes-Benz Forum - M103 low idle speed, vacuum issues causing a misfire?

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Quote:

Originally Posted by johnathan1 (Post 3970139)

Hey, (OP) what ever happened?

HI Guys,

I've given up on trying to get the car to run perfect... Have put 50K on it since I was asking all these questions, and never really figured out what the issue was. some of it was due to the engine not being driven. As I put 1500 miles on it the first summer, things got better. Not great, but better.

That being said there were times when it would idle pretty well and display excellent vacuum on the economy gauge.. That said, it typically gets 20-25MPG depending upon your right foot..

Most of the time it seems like it has a misfire at idle. Hot or cold..

I'm still driving it, and it has been absolutely reliable...

Quote:

Originally Posted by optimusprime (Post 4039131)

Worth checking if you can find it . I no nothing about this sensor so you can teach me on this one .I will keep looking in on this .

optimusprime,

I was doing some research yesterday about the altitude correction capsule. When I looked it up in the Mercedes parts system it says the part is only valid through 1989 for the 300SEL. Now I'm wondering where the altitude correction factor comes from for the CIS ECU.

A little more digging and I found several comprehensive fault code listings for CIS vehicles. For my year, fault code 8 says altitude correction factor from EZL is illogical. So I looked at the EZL housing and there does appear to be some type of breather cap on it.

It would be great to get some confirmation but I believe that the ACC was incorporated into the EZL on later CIS models.

Hope that helps,
Motorhead