Hi Folks,

My S420 1995 would not start after I parked it in the garage from my normal commute. Everything was fine prior to shutdown only an hour before. The engine would crank but will not start at all.

I had an assistant listen to the fuel pump while I turn on the ignition, and it does turn on (hums). I checked for spark to the plugs and confirmed that the ignition is working.

The battery is brand new.

I don't see any fault code lights blinking at the LED display by the modules.

Does anyone have any suggestions on what else I should be checking?

-much appreciate any help!!!

Jim140

Lock and unlock the doors. Then try to start. IF this does not work, use the hey in the door handle to unlock the doors.

IF this fails, I have seen a few starters failing, (and ignition switches.)

The most common thing is the alarm though.

Just riding along. . .
 

Have nothing to contribute but am interested in the final 'solution', so just monitoring.

I think should it be your "alarm system".

Hi guys,

Well, got someone to come over with the whole diagnostic kit (mushroom and all) and found no fault codes anywhere in the system.

I am going to replace the fuel pump and see if going back to basics will work. I know I have fire because I definitely verified it visually. On the fuel pump, I had an assistant listen below the car, but I am suspecting maybe the humming sound from the pump did not necessarily correlate with a functioning pump. I think the car still has the original pump at 110K miles.

Hopefully, it is the pump. I can't think of anything else at this point. There is a lot of fuel in the tank. (1/2 tank.

jim140

Oh yes, I did try locking and unlocking the car, with the remote and with the key. No such luck.-jim140

What happens when you try and start it? Does the engine not even turn? Or does it turn but never catches and starts?

Have you change fuel filter before?? if it wasn't the alarm system, then should be fuel system.

Problem solved
 

Well, it was back to basics. I went underneath and yanked out the fuel pump and fuel filter and replaced them with brand new ones. The car is now back in order!

Didn't really get to nail down which component was not functioning, but you folks were right about the fuel problem. It was definitely either the pump or the filter.

thanks again!

Door Locks / Alarm
 

Hey guys -

Got stranded at a gas station last night. Got out to fill up, then tried to leave. Car would start and die. Over and over. Called my girlfriend to have her search this board and she came across this thread. "Hit the door lock button" she says. I do it, the car starts and runs fine. Seems I left the key in the ignition when I got out and filled up and tripped the alarm. Thanks for the info, this board is great.

- Kevin

Check the connections around the starter motor. My former boss had the exact same situation with his W140as you. Sufficent corrosion had formed and caused a bad connection.

But wait, there's more...
 

Turns out that what I thought was a fix with the alarm system was not a fix at all.

Over the next several weeks, the car stalled immediatly after startup 4 times, only once did it fix with the door lock button trick.

Then I subscribe to Alldata DIY to gain access to the factory service data - www.alldataDIY.com - I really reccomend this - and I find a TSB on this problem.

The car throws a trouble code 17 - bad crank trigger. The TSB says to make a .5mm thick shim from gasket material to space the crank trigger up away from the flywheel to fix.

That seems to have fixed it.

Until next time, that is!