AEM AFR meter on the fritz!

[KnuckleDuster]

Start the car and it reads fine, blip the throttle and the dot pegs full lean and shows three dashes on the digital readout. Stays that way unless I turn the car off and restart, then does it again.

Anybody know why or how to remedy?

Unit is about 1 yr old and was working fine until today.

 

[brian6pac]

Do a recalibrate, you need to pull the O-2 out and start fresh.

 

[KnuckleDuster]

Do a recalibrate, you need to pull the O-2 out and start fresh.

I tried that, turned it on with sensor disconnected, then with sensor in free air outside the car. It did not seem to recalibrate. Sensor didn't look that dirty, either. Gonna dig out the manual, and drop the column to double check power supply under my dash. Car was a little rich at around 12, but wouldn't think that would kill a sensor that quick.Was just hoping someone else had it happen and fixed it to help point me in the right direction quicker. Thanks!

 

[67Dart273]

I would review your wiring layout and connections. Maybe it's picking up electrical interference. how about alternator ripple? (Google it) One quick way to check that is to disconnect the alternator field wire (either one on 70/ later) and try the test again. Check that wiring is not adjacent to spark plug wires, and route harness close to the body.

 

[pishta]

IIRC you can sort of clean them with a torch. Get them hot...



5 wire

 

[brian6pac]

Silicon can also contaminate the sensor so check all your sealer you put the motor together with and see if they are O2 sensor safe, I think all the automotive sealers are but I have seen bathroom sealer used on gaskets. Also don't cut and solder any O2 sensor wires the sensor has to breath and it does it through the wire.

 

[KnuckleDuster]

Well, I replaced the o2 , and it worked fine, for 7 months...
Last night it crapped out again.
Sensors in new cars last for years. Any idea why I'm killing them so fast?
Mounted in the end of the driver's header collector, wiring on the fender apron, not touching the header. Fuel ratio never goes below 11.9 ( at idle). Never found any issue with wiring.

 

[goldduster318]

Are you using lead fuel additives?

Also is the sensor at least slightly angled up (wiring harness above horizontal)? It might be filling with water if it's not.

I have an AEM kit as well, mounted as shown right behind the collector and have not had a single problem.

 

[KnuckleDuster]

Sensor is at about 2 o'clock on the driver's side collector just before the flange. Pump 93 only.