97 e320 rough start when warm

May 4, 2010 | 06:36 PM

stockCRXSi

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W210 E320

97 e320 rough start when warm

97 e320 engine M104.995 L6

I got the sparkplugs replaced at the dealer and shortly after, maybe 2 months or so, I stated having an issue with a warm start. Cold starts in the morning or at any time for that matter are no problem. here are the symptoms:
1. a need for excessive cranking to start.
2. once it turns over, it stutters at 200-300 rpm for 0.5sec and then shots to 1500 or 2000 for 0.5sec and then returns to normal idle.
3.some times it turns over and immediately stall.
4.I have no codes for the ignition of fuel system. (checked with carsoft)
once the car starts there is no stuttering or issues at all. the entire RPM band is nice and smooth and so is the idle.
IDEAS:
1. I ruled out a sparkplug issue since they work better when warm and the issue only appears when the engine is hot.
2. I also ruled out a fuel issue since I repliced the fuel filter and checked fuel pressure. also a fuel issue would present itself throughout the powerband and also in could starts.

any info is greatly appreciated.
thanks.

Last edited by stockCRXSi; May 5, 2010 at 05:49 PM.

May 4, 2010 | 08:08 PM

RichardM98

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From: SoCal

98 Brilliant Silver E320 Wagon

Hard to make snap judgement but it sounds a little like a failing CPS (Crank Position Sensor). Classic symptoms are ok cold start and poor or no warm start. CPS is located at rear of engine below the left cylinder head. It's a little hard to see from above but follow sensor cable.

May 5, 2010 | 05:51 PM

stockCRXSi

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W210 E320

Quote:

Originally Posted by RichardM98

Thanks for your reply. it is very appreciated.

I keep getting the same answer everywhere I ask but I also hear that it is a very rare part to go out on these engines. I have found many DIY for the V6 and V8 but nothing for the L6. I think I found the sensor right above the starter and below the oil filter but it looks impossible to remove if that is it.

anyone knows of any DIY for this sensor on this motor?

thanks

May 5, 2010 | 06:05 PM

RichardM98

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From: SoCal

98 Brilliant Silver E320 Wagon

Gotta curb my enthusiasm. I missed the 104 and gave directions for 112. On the 112 the sensor attaches via a side tab on the sensor with a hole for a bolt. You might go to an online supplier like autohausaz and check out the picture of the CPS for your car. You might check the DIY section at peachparts to see if there's one for your engine. Mostly it's just detach old and attach new. About the same as an O2 sensor.

Good luck.

May 8, 2010 | 03:54 AM

Lancelot

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From: the Netherlands

'01 W210 E320 CDI

I've had the exact same symptons on a W124 with the inline E320 engine and it came down to a leaking injector(s)

May 9, 2010 | 10:28 PM

stockCRXSi

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W210 E320

sensor replaced and problem solved. I even have better fuel milage after replacing the sensor. It was located on the driverside of the engine. right over the flywheel. if you look below and behind the oil filter you will see it. It´s hard to find but look closer.

thanks for all the help!

Jun 1, 2010 | 12:45 PM

stockCRXSi

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W210 E320

Issue returned 5 days after the sensor had been replaced. Still no code with reference to the issue. I am lost here. Looks like the dealer will have to deal with this one.