Working on a 78 450SL that runs good most of the time. Last week it stalled while driving and then would not start. After sitting for 1/2 hour it started and ran fine. The car stalled again the next day while ideling in the driveway. While it was in this condition I checked for spark at the plugs and there was none. Again after sitting it started and ran fine. I don't smell fuel like it is flooding, it is not overheating. I visually inspected the coil and ballast resistors and the blue bracket resistor is cracked in the ceramic from one end to the other, could that be the problem ?

I had Circuit City install a new radio CD player about 2 weeks ago.

This sound like an electronic ignition module problem. I havent had this experiance much with MB's but I have certainly seen it alot with older Fords. Spray water on the module to cool it down and is starts right up.

John Roncallo

Any other suggestions out there?

my 76 450 ran poorly (and stalled) when I bought it.
One issue I certainly had was a clogged fuel system - I ran a couple of bottles of Techron through the system and replaced the fuel accumulator.

I'm not sure how a vacuum leak would lead to the problem you had, except these cars are so prone to vacuum problems and that could impact the idle.

But try the Techron and take a look at your accumulator.

I have no spark at the plugs when this condition occurs. Engine cranks, won't start, let it sit and it will start and run fine for several hours or so., then quits again.

no spark says ignition system, cracked resistor looks like an obvious fault. probably breaks the connection when it gets hot.

wouldn't waste time looking anywhere else on this one

__________________
1987 300e manual 250,000 km (sold)

Put a new blue Ballast Resistor in today, I'll let you know if it does the job.

Do you recommend fuel injector cleaner for normal maintenance ?

there are so many different views on fuel injector cleaner as reg. maitenance. I used it because I bought a neglected car that badly needed all the fluids/systems cleaned out.

Others have made the point that if a car is in tune and you run good, premium gas through it, there should be no need for extra cleaners.
Techron (in a bottle) is apparently just a higher dose of the stuff Chevron already adds to the fuel.

Then again, if a car is in tune, running well, I don't see how a bottle of Techron every 3-5000 miles hurts anything. A lot of people do report good results with the Techron.

I have driven the car for over a week now and have had no stalls !

Replaced the Blue Ballast Resistor that was cracked and the coil for no particular reason other than it looked old......and all is well.

Also, I ran two bottles of Fuel Inj Cleaner through and tightened up the play in the accelerator mechanism.

Thanks to all for the advise

One thing you might consider after you run through this tank of gas.

The injector cleaner, at least on my car, did clearly work, and that it seemed to make my oil dirtier than normal with the residue. Also, it may have worked so well that it slightly
clogged one of my cam oiler tubes, though I can't be sure of that.

But you might want to do an oil change fairly soon. Get the gunk that the cleaner broke loose out of the engine.

Checking the cam oiler tubes is a pretty easy DYI, and a good idea anyway. But it does take some time.