71 300sel 3.5. starts right up cold, runs pretty well all the time.

if i turn it off hot and wait 15 minutes to about an hour its very reluctant to start and when it does it runs rough for about 30seconds.

stuff i know is bad:
vacuum retard leaks
plugs, wires, cap and rotor could be better

stuff thats good:
air temp sensor is new

i'm tempted to just pull everything off the motor, and have the injectors cleaned, replace the fuel lines, the other sensors, and see where that gets me

thoughts? questions?

mike

Them old fabric covered fuel lines can become porous without you even knowing it... running all the way to the fuel tank. Replacing them on my 280SEL last Summer increased "fuel mileage" immensely.

On the rest of your plan, the only thing I wouldnt do is pull the injectors - but run some fuel additives through the tank instead, replacing fuel filters too - or installing an inline filter if the car doesnt have one already.

For what it's worth, the same hot-start problem on 6 cyl Zenith carb 280/8 ended up being automatic chokes working overtime.

240dd-

What was your source for new cloth covered fuel line? I figure mine's about due to be replaced.

hmm the fuel line has been changed, but the mps/map/pressure sensor/round spaceship looking thing has a fabric vacuum line on it still. hmmm

mike

Disconnect the lead to the cold start valve prior to your next hot start and see if that has an impact.

Most definitely replace that vacuum line to the sensor. -CTH

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Joe, Whether or not original MB fabric covered fuel lines are better than regular fuel lines is questionable..... like i said, those things can be leakin like seives and you will never know it. Try prodding a few underneath the car and see if they get wet. I tried to bend one of mine and it got soaked from brittle and cracked internal rubber core. So I used regular American fuel line.... same internal diameter, slightly wider outside circumference..... hardest part is estimating how much footage - easy to underestimate - i had to go back for more fuel line.

You can also replace narrow rusty ring clamps with superior WIDER, stainless steel clamps throughout the car...... especially on radiator hoses - where the pitifully narrow original MB clamps bite into the hoses. You know the ones..... those horrible skinny long screw clamps that you end up mangling for removal after they rust...... The way to go is with wider, rust-proof clamps that dont stress the hoses.

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yeah i remember replacing the charcoal cannister hoses in another car and the outer fabric stays nice, but the rubbers gone underneath.

thanks for the help guys!
mike