I would also check the CPS...for misfires to happen that fast and that bad as the car heats up, that could well be the problem
Be nice to have a scope on that sensor when the condition presents ...........

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A Dalton

Arthur...what is the CPS?

It's a weird thing, it will run good for 5-15 minutes and then start misfiring and then might catch again and run great for a few mintues and then start the cycle over. It is giving no codes when it does it.

We tried a new coil pack int he three locations and this did not work either....

CPS= crankshaft position sensor.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
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Would/Could that explain the engine "leaning out"?

M.B. DOC,

Do you still manage a service department currently? It might be worth the trip (towing it) to Tucker to have the car looked at....

The infamous Crank Sensor gets heat soaked and creates mutiple cyclinder misfires until it cools back down..very common and I am surprised no one has looked into it.

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A Dalton

Mr. Dalton,

I called the shop and asked them to check this. When I spoke with the guy, he said they thought of this but they are not getting the fault on the computer when they check it. previously it did give a fault of multiple misfires detected.

Will it always show up on the scanner as a fault?

Is this a hard part to change out? If not, I may pull the car back and try it myself.

John

Is this an easy sensor to find and change? If so whre is it located on the C280?

John

Any info/help would certainly be appreciated.

If the CPS is bad, would it create a condition where the car appears to be running lean thus causing the misfire?

Would it at times load a cylinder with gas and appear to be loading up?

Is this any easy sensor to change out, where on the C280 is the sensor located?

I appreciate any and all help.

John

The CPS is the trigger for the entire engine management system.

It would be what points would be on an old car.
But new cars do not load up with fuel if the ign does not fire/misfire b/c the fuel is defaulted automatically by the ECU so that the cat can not load up with raw fuel..so if you have a misfire , you automatically have a lean fuel condition....b/c the misfire shuts the gas off to the injectors ...simple

So, if someone simply checks the CPS for output when the condition exist, you will know YES/NO..

It is at the rear of the engine and it is triggered by segments on the flywheel.
I am sure your guys know of this part b/c it is a MAIN hall effect sensor.
Use the SEARCH feature as there is enough CPS sensor info/discription/ and change procedures in there to fill your house. Mainly b/c they are a common fault part on that engine..........................
A 15 sec scope pattern will verify a CPS putput.

http://catalog.peachparts.com/RenderScriptTemplate.epc?_cmd=epccat_VehicleAAA&cookieID=2HB00YPXR2HD0V7J9W&yearid=1997%40%401997&makeid=MB%40%40MB%40%40X&modelid=C%2D280%2D001%40%40C+280+Sedan&catid=F%40%40Engine+Electrical&mode=PA&subcatid=F6010@@Reference+Sensor

All of this info is right there at your keyboard...the part I posted is right at the top of the Forum page..... and the CPS info you seek is right in the Search Feature under "CPS"..and the change is in the DIY section.
All this stuff is right there. I am looking all this stuff up right from the same page you are on. Go to the top of the page and look at the FORUM features ,,that is what they are there for...it will save you many, many post and time waiting for a reply.

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A Dalton

Mr.Dalton,

thanks bunch for the information, I am pretty new to this forum as you can tell. I was aware of the search function but probalby wasn't keying the right words to get what I wanted. I was also unaware of the DIY area. The more I think about this, the more upset I besome at the shop for not thinking about this.

Again thanks for your patience and the help.

John

Very Good..

The reluctance some of us have to go into technical detail on a diagnosis is b/c we have repeatedly done it a thousand times and we know it is right at your finger -tips...

If I have to do a tutorial one more time on aux fans, I think I am going to just barfffff....

Anyway........this forum has more date filed than the CIA...........
..and the beneficary of all the data is the poster who is in trouble....
...and the parts section can be invaluable for a diyer b/c it even has a PICTURE of the part...what else could anyone ask for??????????????????

We get guys who actually ask us to take a picture of the part on that model, with our finger in the picture pointing to the part.....

There are guys who should not be under the hood.!!!!

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A Dalton

Thanks for your understanding.

I am a pretty technical guy, but this Merc is kicking my tail. Hopefully this will solve the issue once and for all, my daughter is ready to get her car back.

Thanks again,

John

Diagnosis is the key and unfortunately guys like you have some skills, but the problem lies in Test Equipment.
Anyone who has a scope knows how fruitless and frustrating a diagnosis can
be on the new cars for anyone attempting to find even a simple ABS sensor fault w/o a scope. The old days of a DMM and jumper wire/test lamp are rapidly vanishing...the Tech has to see what the ECU is seeing, and that requires equipment and some basic electronic skill ....something many shops don't even have.
If one breaks down each sensor and has a basic idea of what/how each works , it is not as technically complex as one whould think...fortunately, the net has such info and tutorials, plus CDs are available all over the place..
..but anyone who is used to doing a decent tune-up on the old chevy is in for an awakening..that's for sure.
Is your problem the CPS...maybe . But if you had the equipment to actually test it, then the maybe goes away.
So, that leaves you the option of having someone diagnoses the part as bad w/equipment, or taking a shot at changing the part with crossed fingers.
..and many on this forum do the later with good results b/c things point in that direction and being a common fault related part..and then again, many change the CPS using this thesis only to report " Well, that didn't work"..........

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A Dalton