Second time starter - PeachParts Mercedes-Benz Forum

Lee Blaik · #1 08-12-2006, 07:59 PM

More often than none my beautiful 560SL would not start the first time. You crank the motor it starts for a second than die, you crank it again and it runs fine. My mechanic talks of a tired fuel pump but I don't hear the wining sound yet. Any suggestions.
Regards to all...Lee

flbenz · #2 08-13-2006, 07:04 PM

I've had starting problems with my 76 450sl and find it does better if I have the pedal to the floor just when I turn the key. I back off as soon as it catches, of course.

But another simple possibility is an old, clogged up fuel filter. If you haven't replaced that recently that might be the most economical thing to try.

Also try putting a bottle of Chevron Techron Concentrate in the fuel tank - you'll see many people on this forum swear by it for cleaning injectors and fuel lines.

ctaylor738 · #3 08-13-2006, 07:56 PM

This could be a bunch of things. I doubt the fuel pump theory, but it is easy to check.

I would first suspect a flakey fuel pump relay. The car gets a whiff of gas from the cold start valve and fires, but the relay doesn't recognize that the engine is turning, and does not power the pump. Then you recycle the relay and the car starts. Easy to test - jumper pins 15 and 86 on the relay, start the car, and see if you still have the problem.

Next I would look at system pressure, which will tell you if you have a tired pump. Then control pressure at cold and warm start. There are very specific numbers for this depending on temperature.

83560SL · #4 08-16-2006, 04:29 PM

I hope that it isn't your starter. I still can not get my starter out of my 1983 sl. the top allen head bolt is behind the transmission fluid tube and under the back of the passanger side head. There is not enough room between the head of this bolt and the firewall to get a regular allen wrench or a ratchet with an allen socket on it. I cut the ball end of the allen wrench off and was able to angle it into the head of the bolt but there is not enough room for my hand or anything else to get any leverage to turn the bolt. I have come to the conclusion that the engine must be pulled away from the firewall in order to change the starter. My knuckles are bloody and my allen wrench is ruined and the starter is still bolted to the bell housing. What is so bad about having two bolts going through the bottom of the starter up into the bottom of the engine block?

t walgamuth · #5 08-16-2006, 06:43 PM

on these motors it is best to depress the throttle about 1/3 on every start up. i learned this from an old mb mechanic.

tom w

Lee Blaik · #6 08-17-2006, 12:33 AM

Tom
You are quite right !!!
That's what I've being doing.
Best regards to all...
Lee

83560SL · #7 09-01-2006, 02:21 PM

O.K. I did manage to change the starter in my SL (had to have a childs left hand transplanted onto my left arm in order to fit it between the firewall and the head to reach the top mounting bolt for the starter motor) but the car still isn't running.
The starter motor turns the engine over but now I fear that the electric feul pump is not working. I am looking forward to finding out how the feul pump is mounted (NOT). Can an electric feul pump be bench tested once I get it off of the car?

ctaylor738 · #8 09-01-2006, 03:46 PM

Have someone crank the engine while you put your hand on the fuel pump to see if it's running while cranking.