Keith Fox

Hey Guys, I have a CLK 500 (2005) that stalls when i really get into it. Sometimes at 80 mph. I have replaced the CPS do to running rough and stalling at stop lights. Those problems went away and when i drive the car like a normal human being it does just fine. What fun is that? Now that my daughter is driving this I am concerned she we try to pass and stall. Any ideas? Thanks in advance...

gixxerboy

has it set you CEL?
Does it restart right away?

Keith Fox

It Starts right back up with no issue and won't be a problem again until I try to haul Butt =)

The CEL code still refers to the CPS. I have replaced it 2X.

gixxerboy

When you replace it what shape is the sensor in?
Have you checked the wiring going to the sensor?

Keith Fox

I was told it had Oil on it so maybe it was fouled. I was also told the wiring harness was in bad shape... I was wondering if the Harness could cause this behavior.

Glyn M Ruck

Is a CPS code the only one stored? You could have a fuel rail pressure issue. Pressure needs to be 3.8bar or 55psi. Could be fuel pump or clogged filter. Your car is right at the changeover point. Could still have an external filter or an in-tank filter at the fuel pump. Make sure that the airbox is clipped down firmly over the MAF at the rear of the engine V. Loose airbox does not throw a code.

It could be the harness but not common.

EDIT: BTW the cause of CPS failure is heat over time due to location. Sometimes pouring cold water over the CPS will revive it for a while.

gixxerboy

if the wiring is damaged it could be not getting the signal from the cps. I agree thats not common but if you keep getting cps codes i would look at it.

I also agree with Glyn, it does sound like a lean issue, that would have been my first thought except for the continuous cps issue

DanielFD

I had a similar issue when i installed a used fuel pump in my old C230 (i was stranded at night and all the shops were closed, my mechanic had a spare unit around) everytime i'd push the car continuously it would stall, ended up changing the fuel pump and it solved my problem. Though STAR should be able to tell the difference between a CPS fault and not enough fuel.

Glyn M Ruck

Fuel pressure should be checked at the Schrader valve on the front fuel rail that connects the injectors at the above values while cranking.