Replacing MAF Sensor

[vanmor]

My 91' 2.3 is running rough. It runs OK sometimes and sometimes it doesn't. When it doesn't, it floods and the cat get red hot. I get a code that says the MAF sensor is reading too much air flow.

I tried cleaning the sensor but it didn't change anything. I've read that if you replace the sensor, you also have to replace the housing. Something about them being calibrated together. Is this true ?

 

[tomw]

can you 'disinterpret' the code meaning from 'too much air flow'? The MAF reports air flow based on temperature and cooling effect of the flow on a heated wire. The wire will change resistance based on temperature, and the computer 'knows' how hot the wire will get because it is controlling the electricity flow that will cause it to get hot.
If there is gunk on the wire, it will report less flow, and also fail to report quick changes in airflow. I don't know how it can 'over report' the air flow, except if it is kept cooler than it should be.
Glowing cat and flooding air excess fuel problems. Did you check fuel pressure? The computer can compensate some, but if the pressure is too high, the injectors will squirt too much even in the shortest bump the computer can give.
I would remove the MAF, and the internal cover, and inspect the wires. Just a small amount of 'stuff' can fiddle with the reading. The wires are DELICATE, so be careful. The MAF is a bolt-on, so it does not care where it is bolted and is not 'matched' to its housing(the air passage that leads to the throttle)
tom

 

[RonD]

You can replace just the sensor, but it needs to be with the same size sensor, that is what "they" mean when that say it must "match the housing"

MAF sensor only samples about 10% of the air flow thru the housing, so if you don't match the size then sample % will change so computer would be getting wrong data

MAF sensor voltage goes up with air flow, its a 0 to 5volt range, internal short in sensor could cause it higher voltage than expected.
The computer "knows" approx. MAF voltage expected at any given RPM and throttle position, because it "knows" it is running a 2.3 Liter engine, i.e. engine can pull in 2.3 liters of air at wide open throttle

MAF sensor is used to fine tune for best performance and economy, by measuring air temp and air density(elevation), i.e. the amount of usable Oxygen in the air that is coming in

 

[vanmor]

i can't find my notes where I read the code. I'll read it again tomorrow and post the results. Maybe i read it wrong.