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Discussion Starter #1
OK, spent all afternoon researching forum for subject while trying to figure out why the car idles really rough, surges, runs at partial throttle, dies at mid power, and if you leave it run for awhile it gets rougher and rougher, then will not start... Two MAFs giving the same symtoms. Questions:
1) Can the crankshaft position sensor be effectively cleaned on the car?
2) Can the crankshaft position sensor be tested on the car?
3) Do I have to pull the aluminum radiator hose assembly off the front of the car to get to the crankshaft position sensor for its removal?
4) I cannot find Lambda sensor on real OEM, anyone got a part number for this?
5) Can you test the lambda sensor?
6) Is there any possibility that these symptoms can be caused by a bad throttle position sensor?

Cheers;

Mike
 

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Mike, being quick as it's late.
You can clean cps on the car it is above the toothed wheel @ about 8 o'clock in relation to the fan if you were standing looking towards the front end of the car.
I doubt that is the cause of your problem.
Have you disconnected the battery for 30min and started the car ?
Is it any worse if you take the multi - plug out of the maf ?
Do you have an air leak ?
Can you try another ecu / dme?
Are the HT electrics ok ?
Does sound like a fueling issue. Have a read through the faq's @ www.bmwe34m5.com
Cheers.
 

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Discussion Starter #3
Yes, I "cleaned" the crank sensor on the car (cloth wiped around the sensor and the small part of the sensor face you can see from under the car, also put a paper towel on the crank, pulled the coil wire, and starter-rotated the paper towel through the 1mm gap between the sensor and the crank - no change) , question is can you really get it clean while on the car? I would expect a sensor code if this were causing this kind of drivability problem...

Don't have a second computer... But the computer must be passing the self test at turn on or I should get a code here as well...

How bad do they run with a bad lamdba sensor???

Mike
 

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I had similar problem on mine recently - turned out to be moisture in the dizzy cap - seemed to be a little rough to start then as she warmed up i guess moisture evapourated/moved around a bit and re-condensed and caused bad running - check your distributor cap just 3 10mil bolts from what i remember
 

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Mine did the same thing and after replacing much of the above discovered water in the Oxy sensor due to someone "helpfully" cleaning the engine...
 

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