MAF Sensor blowing

[stu.waller]

Hi All. Would really appreciate some support with an issue that has confused audi specialists.

The MAF sensor keeps on blowing. When it does the car cuts out. Unplug the sensor, the car runs ok, but over fuels.

Putting a multimeter on the ground pin in the wiring plug, the next to the middle pin I get 4.99 volts which I think is correct.  If I them check the next pin I get 7.3 volts with ignition on and 9.5 volts with the engine running. I thought this was supposed to be considerably less?

If that's the case any ideas where to start?

Anyone know where I can get a schematic for the actual ECU? I'd like to track back through the loom and find where the excessive voltage is coming from.

All help will be very much appreciated. 

Stu

[stu.waller]

So an update on readings.

Been back out to do a better job of recording voltages.

Multimeter on car ground to the following pins: with ignition on but not running 

Pin 1- 4.98v

Pin 2- 0v

Pin 3- 12.19v

Multimeter on car ground to the following pins: car running 

Pin 1- 4.99v

Pin 2- 0v

Pin 3- 14.37v - 14.45v when rev'd

 

Variance between pins 1 and 3 - 9.3v

And pins 2 and 3 - 14.4v

 

All seems normal yet something blows the maf sensor.

Could the Multimeter response time be insufficient to pick up voltage transients?

What am I missing here?  If anyone could provide their voltage readings as a comparison it would be appreciated. 

If anyone has any ideas of what to look at next, that'd also be appreciated. 

Would different measurement equipment be more suitable?  Oscilloscope?

[stu.waller]

So I think that pin 1 is sending 5v from the ecu to the maf in error. Does anyone agree? Pic attached shows pin 2 as ground. Pin 3 routes to B277 positive connection 1 in wiring harness.

Pin 2 should be for maf to to send voltage to pin 22 in ecu, not send 5v to maf sensor. 

So what feeds pin 22? Anyone understand where in the ecu it can produce the 5v? Or where else in the system 5v could be fed into the ecu which is then going to the maf?

It'd be good to know what other wiring I can investigate that could be causing this.

[cliffcoggin]

It's unfortunate that nobody here has been able to help Stuart, but please let us know of progress.

[stu.waller]

Update - received my obdeleven today and plugged it in.

3 persistent faults.

MAF - understandable as unplugged

Fault code 01314

Fault code 01592

Anyone think that either of these could contribute?

Could 01314 be due to maf being unplugged?