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1988 560sl Cold/Hot Starting Problems.. HELP!!!

5203 Views 7 Replies 6 Participants Last post by  BenzToy
My 1988 560SL sometimes takes several seconds of cranking to start up. It sometimes does this with a cold engine, and then it will do it sometimes after having sat for 20+ minutes after being driven. After cranking the hell out of it, it sputters to life then runs smoothly.
I have replaced both fuel pumps, the fuel filter, thermal time switch, ignition coil, distributor cap and rotor, and the cold start injector. The car has 101K miles and once started up, runs very well.

Any help greatly appreciated.
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Sounds like the fuel accumalator. My 380 SE does the same thing but only when hot. The accumalator is located near the fuel pump.
I'll risk to repeat my self, few posts down you'll find my experience with my 450 (much the same engine as yours and EXACTLY the same simptoms).

Everything you had done, I've done too. No success.
Then, I replaced all the injectors (~US$300 in South African currency) and "voila": just a half of the turn of the key and it runs smoothly.
I've found that fault in pressure reservoir is far predominant for "hot start only" problems. If problems as you describe, culptit is that the injectors spray way too much fuel and their holding/leak pressure is way low. Effect is very same as if carburator engine becomes flooded. As another symptom, at every start of the engine a fuel vapour can be felt in exhaust.

Many things that had me puzzled came to easy "why", eg. if the engine/fuel pump immobiliser was "on" I could still start the engine and run it for short time, after replaced injectors that was impossible. Obviously due to injectors leak into intake manifolds engine could have some "food".

Good luck in hunting the problem... however, if injectors do not solve your problem you should at least get better fuel economy...
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Thanks for the replies. To me, it seems as if the car loses its fuel pressure once it has sat. I do not notice any black smoke or fuel odor once the car finally decides to start. The plugs are also very clean as well.

I asssume that there should be fuel pressure at all times, even when the car has sat overnight, or even after 20 min after being shut off. Is this true?

Thanks once again.
Thank you for all the input on my starting problem. I replaced the fuel accumulator yesterday, and since then, the car has acted up. I took it on a 100+ mile run, frequently stopping along the way for periords of 1 to 2 hours, and it always started up just fine. This morning, it started up fine as well.

Thank you once again.
Did you mean to say the car has NOT acted up??
Don36 said:
Did you mean to say the car has NOT acted up??
You have a keen eye, Don. Did you happen to notice the posting date?
Nobby Clark IS a Shark

knobby said:
You have a keen eye, Don. Did you happen to notice the posting date?
Keen eye yourself Nobby.;)
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