1979-1993 & 94 Conv [Subscribe to Daily Digest] |
OK, with help from you guys, this site and a failed emissions test with very high NO emissions, I'm satisfied that I have a problem with my air mass meter or its circuit. Upon start up I get a reading from the O2 sensor of .48 volts. After some seconds that reading starts to decay slowly. If I remove the vacuum line from the fuel regulator it will come up some but continue to decay. Vacuum line back on and it drops quickly and then slowly continues to decay. If I rev the engine I can get a response on the decel side jsut for a second that tells me that the O2 sensor is working. That and the fact that NO emissions were double what they should be.
So something is telling the computer to lean out the mixture which I can only assume is AMM. I guess I'm missing something though because if the computer is actually seeing the O2 sensor data I would think that it would enrichen the mixture to the point that it floods the engine. Also the first time I checked the O2 sensor it was reading .8 volts at warm idle. Since that time I have replaced the turbo bypass valve, muffler, and measured the resistance of pins 3 and 6 on the AMM. After that is when I started getting these readings, (although my first good readings could have been flukes). I adjusted the AMM to 380 ohms today to see what if any effect it would have. I can make adjustments at the AMM and see a corresponding change at the O2 sensor output voltage, but it will continue to decay.
What am I missing here? Does that sound typical of AMM failures? I'm going to get a fuel pressure gauge to see if my fuel pump is keeping up. That decaying voltage reading has got me baffled.
posted by 216.23.52...
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