My car is a 1991 Mercedes Sel 420. I get up in the morning and I start my car no problems at all, I can drive for hours and have no problems but as soon as I turn it off and go in a store and come back the car hesitates to start. I crank it on it starts for 5 seconds then it shuts down, after about the third or fourth try the car stays on. Sometimes I get it started and take off 15 seconds later my car shuts down with lights all on the instrument panel. My car never idles different through out the day. Its so weired!?!. I was thinking that it may be a FUEL CHECK VALVE or FUEL ACCUMULATOR. Can someone feed me some hope!!!

Does it start more easily if you hold your foot on the accelerator?

__________________
Andrew
300e 294,000mi
380sel 185,998mi
380se 309,980mi

I dont even have to give it gas just a few attempts cranking her. Sometimes I leave the key on the on position just before the crank and let the fuelpump work a little and that works once in a while. Again once I have her started the engine is not starving for fuel or anything rides like a dream.

Try having you foot on the throttle when you fisrt start cranking and see if that helps. I have found that if the injectors are leaking down, they create a rich mixture as the car sits. holding the throttle open allows more air to enter as you crank and this helps lean the mixture out and the enigne starts more easily.
Let us know.

__________________
Andrew
300e 294,000mi
380sel 185,998mi
380se 309,980mi

Same issue do you think it is a FUEL ACCUMULATOR or FUEL CHECK VALVE or neither since it starts at cold starts just fine. PLEASE HELP!!!

I had a car that did this. Replaced the accumulatro and check valves, still exactly the same except pcoket heaps lighter. I then decided that, because it started more easily when I put my foot on the gas and then when it did start blew a little black, rich smelling smoke, that it could be the injectors leaking down. I replaced them and it fixed it 100%.
Symptoms were,

-Hard to start when hot and left for 15 mins or more (if I restarted before 15mins it would start fine)
-Started quicker if I helpd my foot on the gas.
-No problems starting when cold.

__________________
Andrew
300e 294,000mi
380sel 185,998mi
380se 309,980mi

how difficult was it to replace the fuel injectors? do you have any info about it, maybe a suggestion for a repair catalog?

You may try a bottle of Chevron Techron to clean nozzles. But, If they are in fact dripping in a "hot soak' condition, it is probably too late.
If you replace them do replace both o-rings and watch out for broken nozzle holders also.
dpk

All god advice. The hardest part of the fuel injector replacment is cracking the nuts on the injectors. It is a little akward to get tools in there. Other than that, quite easy. I bought genuine bosch injectors but not through benz and they cost me AUD30.00 each. So about US$135.00 all together. But do the diagnosis as discussed first. Don't just throw money at it.

__________________
Andrew
300e 294,000mi
380sel 185,998mi
380se 309,980mi

I replaced the fuel check valves in both fuel pumps then also replaced the fuel accumalator. I still have the same problem I also noticed few posts up that they had rich black smoke coming out when starting, which I have the same issue I'm going to bet its leaking fuel injectors (wish I would of done that first) but at least I narrow it down more thanks!

Please let me know if the injectors work. I have changed the pump, accumulator, filter and injectors and seals still same problem although the cold start is now much better. Someone mentioned check valve and fuel distributor O Ring which I think I'll try.

Before I do the injectors I thought why don't I clean the throttle body out with a spray cleaner. My problems got worse now my car stalls at lights when I come to a stop, or I'll drive on the highway and my steering gets real stiff and I have no acceleration, then all in sudden it comes back and I have power. I hope someone out there knows what i'm talking about? please help.