PeachParts Mercedes-Benz Forum - View Single Post - New to me W126 300SEL Not running well at all

dinman · #1 04-07-2019, 06:51 PM

Hello everyone,

Never have been on this side of the forum. I have 3 w123 diesels, but this is my first older gasoline mercedes to mess with.

I will upload pics of it later when i get back into my Flickr acct.

White/Grey, 1989, 300SEL, 188k miles. A friend of a friend messaged me yesterday asking if i wanted it since he knows i like these older mercedes.

$700, clear title

Paint is excellent. Body has some minor dents.

Front seats are pretty ripped up, power functions work. Rear seats are perfect.

Good suspension components. No fluid leaks.

A/C, not sure, Blower motor wont work.

Here's the big issue i need help with ( i know it could probably be a slew of things)

The car runs terribly. No overheating or anything, but upon cranking it, it idles smooth for a second, then starts surging and such. If you *lightly* give it throttle, it will actually smoothly rev up to 3000 RPM, and sounds excellent doing it. But anything over that, it stutters and dies.

The longer it sits running, the worse it gets. Surging when idling, etc. If you really give it some throttle, it will either die, or drop to about 500rpm and idle bad until you give it some light throttle.

So i know it has been sitting since 2010. Very first objective is to drain every bit of 9 year old gasoline out of it, and inspect the tank. Will need to look into how i go about doing that.

Then i guess i need to inspect all fuel related filters, etc.

Also- need to check fuses.

I just got the car home last night, and its been pouring down raining. SO i haven't really gotten off in it.

Who knows, it has a 1/4 tank of 9 year old gasoline in it. But it was only $700

Any tips from anyone that has more experience than me with the m103?

Thanks!