All of the sudden my 200 S430 won't start. I turns over as if it is going to start, but after the starter disengages it stops. I recently put some techron fuel injector cleaner in it and am suspecting a fuel filter, but am surprised that it won't at least start. Yes, it has gas in it.

It did the same thing a few days ago. I let it sit over night, and it ran fine and started fine the next day. I used it for the day without a problem.

I remember decades ago when a bad ballast resistor was the cause when a car would run with the starter engaged, but quit when it disconnected. I think the days of the "ballast resistor" are behind us, but it does the same type of thing.

I did try to push on the accelerator as is was turning over, and it does not change anything. so I am not acually sure it is actually "running" when the starter is being turned over.

Any ideas?

 

I think you are going to need to get the codes read on this one. It may be some thing as simple as a fuse Look at the fuses under the hood just for the heck of it.

Another "voo doo" thing to try is: Turrn the switch to the on position...press the gas pedal to the floor slowly 3 Times....after the third time, turn the switch off with your foot on the floor. Try starting after all of the above. I used to have to do that on a 735 BMW I had. I think it resets the ECU..I'm not sure but it's free so try it.

 

Thanks for the info. It started again for me, but the next time it happens, I will definitely try your suggestions.

 

Finally solved the "starting problem". Let me give you recap of what happened with this car.

RECAP: I used Techron Fuel Injector a month or so ago, and after going through a tank of it, the engine died one day pulling up to an intersection. It would not start back up.

I let it sit for a while, and then it started. I didn't happen agan for a short time, and I really had no idea as to what it was, but thought it was something electrical like a relay. My 1992 500 SEL did it a couple of times, and tapping the fuel pump relay in the trunk solved the problem.

It happened a few more times, and I theorized that the Techron Fuel Injector cleaner must have cleaned, not just the injector, but also the tank and the residue plugged up the fuel filter enough that it couldn't maintain the pressure required for the engine to run.

The later model Mercedes Benz are designed that if there is insuficient pressure on the fuel system, it will shut down, and will not start. I am guessing it is to keep you from pulling out into traffic, and having your car stall at an in opportune time.

I replaced the fuel filter, and everything seemed fine for a few days, and then it died again, and over time it got worse. I came to the conclusion that it wasn't electrical (and was thermally related) since it would only die when I was at idle, or a low RPM, and never died when I was driving down the road, or kept an RPM above 2000.

My decision that it was thermally related was because it always worked fine after the car cooled down, and it was likely a fuel pump motor heating up, and then failing to maintain the proper fuel pressure the computer system requires. The reasoning that it would not die at a higher rpm was that the voltage provided to the pump (because of the alternator rotating faster) was greater at the higher RPM and sufficient to maintain a higher pressure.

I used my Fluke infrared thermometer to measure the outside temperature of the fuel pump before and after it ran for a while and noticed the temperature rapidly rise after starting the engine, suggesting signficant friction with the motor (from a worn bushing or bearing) or a short in the windings.

Though every other Mercedes Benz I own has the original fuel pump, and several of them have over 200,000 miles on them, I believed it had to be a fuel pump, and so I replaced it.

The problem is now solved. When I purchased it, I had the Mercedes Benz rep look up to see if others had replace them, and they had replaced 10 in the last year at this one dealership.

Hope this helps any of you. This S430 has 130,000 miles on it, and it looks like they all have a problem.

 

Its your MAF, take it off and clean it or buy a new one(Bosch)about a 150.00 from a independent parts dealer or ebay.

 

I had an issue with my car starting also, and it would also cut off after driving for a little while and after taking it to the dealer and doing some personal research it was determined to be the Crank Position Sensor! It was an easy fix. You could actually fix it in a matter of 10 minutes, for real. and the part was only 70.00 at an import auto part store but more for the OEM part at the dealer of course. After replacing the CPS sensor I never had the problem again!!!!

 

Which later models do this... How do they know if the fuel presure is low they dont have a fuel presure sensor.. Ive had cars with bad pumps running at 1-2 bar (14.3-28.6 psi) of fuel presure and they would run.

 

Thanks to your post. My car was not starting yesterday with same symptoms and after I read your post I immediately bought a new pump and changed. Issue solved

 

Thanks for sharing the info. Any other symptoms prior to this event? Was the fuel pump loud/whining etc?

 

fuel pump is the second suspect behind a crank position sensor . Usually when a car dies when warm but will restart after it cools off its a bad cps

 

Tusabes,
you are right but in this case, car was starting after cooled down and never dies when it is idle.
I remember when I had issue with CPS, it was starting when cooled down but dies when idling.


dcsimmons,


there was no loud/whining from fuel pump


* changed fuel filter 1 year-15000km back
*symptoms started 10 months-13000km back


symptoms during 10 months;


1) When car is hot, car will crank 4-5sec and start, this happens occasionally


symptoms during last 1 month;


2) Car wont start when hot
3) Car starts when cooled down
4) Car wont die when hot on idling


final stage 2 days back;


5) Car wont start at all when its hot/cold




care should be taken while changing the pump, unfortunately my tank was full when fuel pump died and static pressure at the line was higher than I expected.

 

update;
I just full my tank after I changed the pump and after leaving the petrol station car stalled on the way. This time it was starting but immediately turns off. I manage to come to home with stalling/starting and put the car in garage. After 6 hours I tried again, no luck. it stalls immediately after start. I didn't change the fuel filter while changing the pump, so I changed the filter this morning and it started again.


However existing fuel filter doesn't look like clogged. So I don't think that it was the fuel filter.


Can be a problem with canister?

 

Cam Position Sensor would be my 1st suspect

 

Wrong post