i have a 89 300se.iam in pa and the car is garaged.my problem is the car starts differently all the time.it could sit a week or a day sometimes i just touch the key and it starts other times it may take 3 or 4 tries and it cranks forever.once its warm i have no trouble restarting it.ive changed the original cap, rotor ,and wires and also put in plugs.are the fuel pumps on these cars noisey ?mine has a good hum to it.one guy told me it may need an o2 adjustment.i just dont know if my problem is fuel or electrical or maybe even a bad sensor.this may sound crazy but the exhaust from the car really smells funky.i run 94 octane in it so bad gas shouldn t be an issue.has anyone had a problem like this?does anyone have any ideas on what it could be?i just dont want to start replacing parts we all know they are not so cheap. thanks in advance. ed

There are many things that can cause hard starting. I would start with the fuel system. The best thing to do is to hook up a fuel pressure gauge and monitor the pressure.
If you don't have one, start by checking fuel accumulator and pressure regulator. These can be checked without gauge.


Vin

have not figured it out yet.the car is in the shop as we speak.the car is going on 13 years old and ive read all this stuff about gas tank cleaners.iam going to say the fuel filter is either original or at best very old.iam going to replace the filter for peace of mind .would it be a good idea to first run some cleaner in the tank before i change the filter?or forget the cleaner and just change the filter.the only gas i run in the car is 94 octane .if anyone hasnt figured out yet iam not a master mechanic or even a mechanic for that matter.i do the easy stuff such as oil changes,plugs;filters and that sort of stuff.i leave the hard stuff to the people that do this for a living.thanks in advance. ed

I don't recommend fuel additives. Just replace the filter. While you are down there check the fuel accumulator. The accumulator is right next to the pumps and filter. There is a small hose with a clamp on the accumulator nipple. Run the car for a while to build up pressure. Shut off car and disconnect that small hose. No fuel should flow out of accumulator.
You should really have someone hook up a fuel gauge. This way the pumps, check valves, and accumulator can be checked quickly.

Vin

I had a similar problem with a 190E and it was simply due to a disconnected vacuum hose.

this is an update to my original post.a highly reguarded mechanic looked at the car.he has found nothing wrong but my problem still persits.he had the gauges hooked up and all.pressure is fine and all else is normal.we have changed a noisey fuel pump,fuel filter,spark plugs,plug wires,cap and rotor.no matter what the temp is, when the car sits in excess of 12 hours it takes forever to start.once started its fine,drive it 20 miles or 200 shut it off for 1 minute or 8 hours it starts right up no long cranking.extended periods of sitting seems to be the problem.can i have a bad fuel relay or maybe half bad?has anyone ever experienced such a problem?the man says everything is ok.everything is not ok and wont be ok when i burn up the starter or battery.suggestions???????????????? thanks ed

re update.when i picked up my car the man didnt have much time to talk was kinda busy.anyways the car sat all night when i went out the next day it started right up instead of cranking for 5 or 6 seconds it now starts in less than 3.called the man and said you had to have done something because the starting has improved.he told me he went over all the grounds on the car and did a o2 adjustment.problem fixed!!!!!!!!!!