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You have vcds; so, i would view live data; while monitoring the readings, do a “wiggle test”, of the plug, wiring going to the maf. If the signal drops out or is a intermittent connectivity issue; you may need to replace the plug, terminals or buy a “pigtail” with new terminal wires, plug pre-assembled, install with adhesive lined butt connectors.

Check the part # on the plug housing; to help you get the correct replacement pigtail:


Butt connectors:


Note: doing a maf test; 2nd gear @ wot, can confirm maf operation, its ability to perform at normal levels at idle up to max ranges, logging with vcds can make this easier, safer, on your test drive.


 

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Note: when a sensor like a cam or crank/engine speed sensor are failing; a code will typically be thrown. For any sensors you decide to replace; stick with high quality oem Bosch.

Any particular reason, you decided; to replace the cam sensor, was there any related trouble codes?
 

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Discussion Starter · #23 ·
I decided to replace the camshaft sensor because of my analysis of the wiring diagram related to fuel system. During my troubleshooting while it was in a no-start condition, I had narrowed the problem to fuel injectors not firing. I had confirmed fuel pressure to the rail and firing at the plugs. It tried to start with a shot of starting fluid in the intake.

I decided on camshaft sensor since I had already replaced the crank sensor a while back when having the intermittent stalling. I had also replaced the MAF sensor (twice in case it was a bad one) due to the code and have done the wiggle test and watched the measurement values.
 

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Discussion Starter · #25 ·
It seems to be running good as of this morning. Started and let it idle for 30 minutes in the driveway. Wife drove it around town, also.

I'm going to put VAGCOM on it this evening and do another scan. I'll probably drive around some as well and log some values from the engine. What values do you suggest?

I'm thinking probably the following: RPM, Coolant Temp, MAF volume, Intake Air Temp, Lambda / fuel mixtures, timing advance, 02 sensors
 

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Yeah, since you are having issues with the maf trouble code; definitely, the MAF values! Remember, you want to see the values @ idle and WOT in 2nd gear, to see the MAX the sensor is able to read, MAX flow the engine is capable of producing.

Quoting the Ross Tech bulletin for maf testing:


fuel trims: Measuring Block Group 032.

Check the output of the MAF sensor while doing a full throttle run in 2nd gear, as shown in Figure B. On most current VW/Audi engines, the actual MAF value can be found in Group 002, field 4 or Group 003, field 2. Assuming this test is done at or near sea-level, the peak output of the sensor in g/s should be roughly 80% of the rated horsepower of the engine. For Figure B example, if the engine is supposed to produce 200hp, a healthy maf is expected to produce a peak value of about 160 g/s.


Were you able to do a "wiggle test" of the maf plug/wiring; while, the engine is running and view the maf values in VCDS?
 
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