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S550 4matic
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It died twice like that in two weeks period, but then restarted fine. This time its cranking but not starting. How do i check if fuel pump working? Also could be crank shaft position sensor? Ill get scanner today, to see what comes up.
 

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Hopes & Dreams
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likely to be one of those two, for me it was the fuel pump
 
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How do i check if fuel pump working? .

Have someone turn the ignition on for you while you're under the car listening to the fuel pump. If no sound from the fuel pump when ignition turn on, use a voltages meter to measure and see if any voltages going into the fuel pump. If no voltages, then your fuse or relay is out. If all the above is fine, then do like the weekend mechanic usually do, disconnect the fuel line labeled "out" and point the hose into a container then have someone turn the ignition on for half a second. You should see fuel coming out. If there's fuel coming out, then it your crank position sensor that's giving you intermitted problems. Good luck.
 

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W203 modified
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Have someone turn the ignition on for you while you're under the car listening to the fuel pump. If no sound from the fuel pump when ignition turn on, use a voltages meter to measure and see if any voltages going into the fuel pump. If no voltages, then your fuse or relay is out. If all the above is fine, then do like the weekend mechanic usually do, disconnect the fuel line labeled "out" and point the hose into a container then have someone turn the ignition on for half a second. You should see fuel coming out. If there's fuel coming out, then it your crank position sensor that's giving you intermitted problems. Good luck.
May as well do the crankshaft sensor first seeing as they need doing every 5 years. And it doesnt show up on any scanner.
 

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S550 4matic
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Discussion Starter #6
Thanks for help, I think its CPS, cause car did started next day when it cooled down, getting stuck in Wendys drive by was priceless:) . I got new CPS today, will install it myself, I see how it runs tomorrow in 90+ temps.
 

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Hopes & Dreams
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Let us know how it goes man, I hate that issue. I never had it when I was driving, thank God, but it was while I was warming up the engine, as soon as it warmed up a bit, it cut off. Maybe because for me it was the fuel pump like I said, but good luck!
 
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getting stuck in Wendys drive by was priceless:) . .


Lol.......I know the exact feeling !! I remember the first time I open the top on mine Slk at the traffic light and in the middle of roof being open, the light turn green and so I have to go. All the sudden, the roof stuck at the highest point and loud beeping alram sounded while the car is moving. 30 second later I then realize that the roof won't open if the car is moving faster then 5 mph. I was so embarassed and people was looking at me like an idiot !! :D
 

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S550 4matic
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Discussion Starter #9
When I replaced CPS, also noticed that something called Breather hose (Partial load crankcase Ventilation), the hooked to the right was split open. Will that cause a dirt to get inside the engine? Should I do engine flush?
 
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When I replaced CPS, also noticed that something called Breather hose (Partial load crankcase Ventilation), the hooked to the right was split open. Will that cause a dirt to get inside the engine? Should I do engine flush?

Well, is there any blow-by valve attach any where on the line? If there is then the answer is..............yes !! Most breather hose have a blow-by valve to only release air pressure but not allow air to suck back in. I don't know about the Clk crank breather hose but I replaced my Slk crank breather hose and there's was a "blow-by valve" attached to the line. So my guess is, there should also be a blow-by valve on the Clk crank breather hose.
 

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2002 430clk;2005 Yamaha YZF R1;08 Range Rover Sport
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I hope I never have the CPS issue, I hate to be somewhere and need to push my car
 

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2005 CLK55, 2014 Acadia Denali
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Perhaps the same problem (CPS)...

When I replaced CPS, also noticed that something called Breather hose (Partial load crankcase Ventilation), the hooked to the right was split open. Will that cause a dirt to get inside the engine? Should I do engine flush?
I think I've got the same issue - bad CPS. Car usually fires up instantly, but started to be a little long on starting.
Today she fired up perfectly, I drove 2.5 miles to the bagel joint, and when I came out she wouldn't start.
Cranked just fine though.
2 hours later I walked back from work and it started up right away.
2 hours after that, no starting again.

I couldn't find a replacement CPS on NAPA online - where did you get your part? Anyone know the best place to get MB parts?

Thanks for any help!

- Dave
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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S320 CDI - 2007
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Thanks for help, I think its CPS, cause car did started next day when it cooled down, getting stuck in Wendys drive by was priceless:) . I got new CPS today, will install it myself, I see how it runs tomorrow in 90+ temps.

The same happened to me last week. My CLK stopped in traffic jam. That made me additionally nervous. I am not much of an expert in all these things. I just waited some fifteen minutes. And it started again. The same day and the next day everything was OK, so I thought it is just incidental problem. However, it repeated two days later. And again, I waited 30 minutes (engine was hot and also outside it was over 30 deg.C) and it started. So I drove directly to the dealer. Crank position sensor was changed and now the car is even better while driving than before. But... it was quite costly.
 

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02 CLK 55
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Replacing the CPS is not something that you want to wait to fix. The good thing is...it will ususally fire right back up the first couple times...
 

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1982 Mercedes 240D
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Okay, I'm having a problem where it's not even cranking when I try to start it. It's not the battery, 'cause I just put a new one in. I got a charger thing and hooked it up, but it's still not starting. What all do I need to look at (other than the alternator)?
 

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CLK 55 Cabrio (Cabs or nothing)
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Sounds like a CPS or a remote chance that it's the Voltage Regulator which probably it is not as that issue will just keep draining your battery (it's a recall freebie).

Okay, I'm having a problem where it's not even cranking when I try to start it. It's not the battery, 'cause I just put a new one in. I got a charger thing and hooked it up, but it's still not starting. What all do I need to look at (other than the alternator)?
 
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