I have aquired a 1981 240dl. Well, it had been sitting for 2 years, but I got it started after some fresh gas and 2hrs of my time. Well with the exception of a little pre-ignition, it ran pretty good. NO BURING of oil WOW!! So, now I have a new problem, when I get it started, she runs pretty good, until it gets hot. It wants to stall and has low pickup during acceleration. The only twist to this, when I put it into reverse, she will spin the tires, with absolutely no hesitation or stalling. I do hear a groan under the car. I was told that this was from a bad internal fuel pump. The external one is fine. ANY IDEAS!!??

 

I assume that this is equipped with the CI injection system, not the Bosch LH electronic injection ?If it is, then there is a pretty good possibility that something is gummed up from sitting that long. I would try a couple of tank fulls of premium ,with a bottle full strength injection cleaner added like Chevron Techron ( and maybe even a bottle of drygas thrown in for good measure) ,and see if it clears up.

 

Yes I have the ci injection. Well I learned something else. I drove it for awhile today and no matter forward or reverse it stalls. It will not even run when it is at full opperating temp. When she stalls out, I can start it back up, the rpms go up and settles for a second and then sputters and dies. When it cools back down it runs fine/better. Right now it died down the road, and i had to get someone to bring me back. I will bring it back later. I am all out of ideas. If it is gummed up, what is gummed up to prevent it from running correctly? Fuel pump seems to have plenty of pressure.
Thanks!

 

Might be a bad coolant temp sensor.

 

wow this is an old post..i have an 1981 242 DL doing the same thing ... backfired so bad it blew apart the muffler ... So did you replace the coolant temp. sensor ?? if so. did it solve the problem ?? If not, have you and what did ??