Hello all i recently purchased a 69 280se coupe i love it fantastic car. I havent had a chance to go though the specs and adjust everything i di get the mercedes service manual on cd from the classic center. Im lucky it is only 20 minutes from my house. I have been experiencing very poor mpg about 7-10 mpg. The car seems to run pretty good but not sure how its supposed to run since its a new car to me. Anybody out there with a 280se that has got mpg figures to share or anything to check that has hurt your mileage in the past. Thanks alot its great to have a a forum to help with these cars.

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You're 280 should be getting much better mileage than that, but it's easy for them to fall out of "perfect tune" and plummet into the 10mpg range. A good member to ask would be 280SEguy (oddly enough) Does the exhaust smell like it's running rich?

Jive Turkey,

Thanks for your vote of confidence , but at this point we don't know what engine is in the 69 280SE coupe he has. I saw this post yesterday but without knowing if the engine 2.8 liter or a V8 I did not respond. If it is a 2.8 liter mechanical fuel injected engine he should expect between 20 and 21 MPG on highway driving and 16 to 17 on city stop and go driving. Those MPG's will only be obtained if the foot is not hard on the gas peddle and the car in perfect tune all around.

280SE Guy

The picture is of a high grill car so it must be a 6cyl.

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Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT

Hello all thanks for the replies. My car is a 2.8 i6. I have been reaing all day on the fuel injection troubleshooting provided by post by arthur dalton. I would definately like some help from 280se as he sounds like he might be someone with much experience on this particular engine.
As arthur pointed out a first step is to get the timing and dwell right. I have the mercedes service manual on cd i got from the classic center and for the life of me i cant find any timing or dwell specs. So if anyone out there has specs for a 69 280se inline six in a coupe i would appreciate it or if there is a link to a web page for help. The car is in great shape and runs good but definately smells and seems to be running rich and misses a little so would like to get a good baseline on it. Thanks ahead of time

I've got a couple shop manuals that might have timing and dwell specs in them, but I'll have to find 'em.

I looked in my old chiltons. It does not give it by year but by model. I am giving the specs for a 280se/8. I am not certain that is your car but believe it must be based on what I have here to look at.

initial timing is 2 degrees after tdc, with vacuum. Max advance seems to be 30 degrees at 4500 rpm and 12 to 19 degrees at 1500 rp, without vacuum.

point gap is .012 to .016 and dwell is 37-41 degrees.

Hope this helps.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

great thanks for the info set the timing this morning dwell looked good at 39ish. next step i guess is to take apart that cold start device on the injection pump. I went by arthur daltons instructions on other post and i still here a little air i think coming out of that filter on the injection pump even when fully warm. I double checked it by not being able to get the injection pump lean enough with the thumb screw on the back. i seem to get at least 1100 rpm if i turn up the air screw. And it will stall out when i turn the air screw in so i know there is no air leaks.

You can't go wrong by searching for and reading Arthur Dalton's posts on the forum. He is the master tuner of these motors, he once said he could tune them in his sleep. I have great respect for the knowledge and mechanical abilities he has.

Another site for good information on your motor is the W113 site

280SE Guy