A4 not running after changing mass airflow meter
Discussion
Why did you change it if it's working?
If you have a good one and the right kit then back probe all the connections. See what they say. Then compare it to what the new one shows. A wiring diagram will be needed to understand what should be going on. You will have a live and ground and usually a couple of signal wires.
If you know what the signal wire is then you can also use an osilloscope to see what is going on if you have one. But most folks don't.
And there is the possibility all of this has nothing to do with a MAF sensor if you have disturbed something else. But if it's working with the old one again I doubt it. My best guess would be something relating to grounding on the new sensor. You can easily test for this with a DMM.
If you have a good one and the right kit then back probe all the connections. See what they say. Then compare it to what the new one shows. A wiring diagram will be needed to understand what should be going on. You will have a live and ground and usually a couple of signal wires.
If you know what the signal wire is then you can also use an osilloscope to see what is going on if you have one. But most folks don't.
And there is the possibility all of this has nothing to do with a MAF sensor if you have disturbed something else. But if it's working with the old one again I doubt it. My best guess would be something relating to grounding on the new sensor. You can easily test for this with a DMM.
milkround said:
Why did you change it if it's working?
If you have a good one and the right kit then back probe all the connections. See what they say. Then compare it to what the new one shows. A wiring diagram will be needed to understand what should be going on. You will have a live and ground and usually a couple of signal wires.
If you know what the signal wire is then you can also use an osilloscope to see what is going on if you have one. But most folks don't.
And there is the possibility all of this has nothing to do with a MAF sensor if you have disturbed something else. But if it's working with the old one again I doubt it. My best guess would be something relating to grounding on the new sensor. You can easily test for this with a DMM.
Thanks for the tip and considered doing this but didn't fancy dragging my nice clean digital scope into the garage. I've got an spare one I'm meaning to sell (Rigol 50MHz). Reading around I'd need to measure the frequency of the pulses. If you have a good one and the right kit then back probe all the connections. See what they say. Then compare it to what the new one shows. A wiring diagram will be needed to understand what should be going on. You will have a live and ground and usually a couple of signal wires.
If you know what the signal wire is then you can also use an osilloscope to see what is going on if you have one. But most folks don't.
And there is the possibility all of this has nothing to do with a MAF sensor if you have disturbed something else. But if it's working with the old one again I doubt it. My best guess would be something relating to grounding on the new sensor. You can easily test for this with a DMM.
I changed it because the car didn't feel anything like as fast as it should be 160bhp and the garage agreed. They suggested the MAF might be faulty (or clogged) as this is frequently the issue - it had shown a fault on their system.
I can now hear the turbo spool up and there's a whoosh when changing gears so I am pretty sure it is down to a poor seal on the vacuum system - an ODBC2 reader has also suggested this. The diagnostic system is getting a reading from the new MAF.
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