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Registered
E-320
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86 Posts
Discussion Starter #1
Hi,
On my 99 E-320 often after turning the igntion when starting the car, it starts but immediately the engine dies and then the second time it comes on fine. This has been happening for some time.
I even put some Chevron techron fuel injector cleaner and it has not helped much. I took the car to the mechanic and there were no codes , he even removed the throttle body and cleaned it but the problem does not seem to have gone away.

it happens like once or twice a day when starting the car.

Any ideas on what could be going on with the car?

Thanks in advance.
 

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Registered
2000 Black E320 4Matic
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77 Posts
I had that issue with my car and it turned out to be the CPS. You should also try cleaning your MAF as well.
 

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Registered
E-320
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86 Posts
Discussion Starter #3
okay Thanks so much.
What is CPC ? how do you clean the MAF ? can you please help
 

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Premium Member
2001 E320 - Brilliant Silver/Ash: 107,000+
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17,193 Posts
CPS = crankshaft position sensor, more info in stickys

MAF = mass airflow sensor, see the stickys for cleaning it.
 

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Premium Member
2012 Mercedes Benz E350 22K Miles
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216 Posts
I have the exact same problem now. I changed fuel filter and there was no change (needed a new one anyways). My next step was the fuel pump but I had not heard the CPS suggestion before. Might look into that as well, are there any other symptoms associated with a bad CPS? Another note, it does not do this every time I start the car and it seems to be almost as often when hot as when cold. If the valve was bad, wouldn't it happen more consistently?
 

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Registered
2001 Mercedes Benz ML430 w163,2008 Mercedes Benz CLS550, RIP Mercedes Benz 1996 e320 w210
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520 Posts
Well with bad CPS you can also get a sluggish acceleration. Also CPS tends to go bad as temperature goes up and fails mostly when the engine is hot.

This is because CPS is a magnet and heat weakens the magnet(if the heat is high enough it actually cause demagnetization of the magnet.)

So cooling off the engine won't help because ones the magnet is demagnetized it will not become magnetized again.

This explains why the first symptoms of CPS failure occur when hot; the magnetic strength of the CPS progressively weakens with time and heat until it is eventually too weak under operating temperature and the car just dies as if turned off by key with no warning like a kill switch.




Sent from my Autoguide iPhone app
 

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Premium Member
2012 Mercedes Benz E350 22K Miles
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216 Posts
UPDATE:

After months of just dealing with the intermittent stalling when I start the car, I may have found the solution. After my head gaskets finally began leaking more than just the occasional drop, I figured it was time to get dirty. Despite the great DIYs on here, I decided to have my trusted mechanic do it. Although I was going to change the spark plugs myself, I figured since he already had a clear shot, why not pawn that job off as well. It turns out, some idiot mix and matched a variety of plug types (previous owner) and they all looked like crap. Good news was that the valves, rods etc looked pristine, free of engine sludge. After replacing both gaskets and changing out the plugs, the oil leaks have stopped and my stalling problem hasn't happened again yet. If anyone is having a similar problem, and other symptoms (like a bad CPS), a simple tune up might just be a good place to start..... and it's a lot cheaper than replacing injectors and/or a fuel pump.
 
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