Thread: Carb Issues on drag car

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Originally Posted by 34_40

I agree with Roger. the "jumping" AFR ratio is what we were discussing. My other thought was the gauge or sensor had a malfunction.

Where is your O2 sensor that drives the A/F indicator located in your exhaust? Is it possible that when you stopped at idle you got a "backwash" of ambient air to your sensor, or that you have an exhaust leak that started sucking air as you dropped to idle? The guy who helped with some EFI tuning mentioned to me that the clamp on sensor that he used was good with the revs up, but questionable at idle when exhaust pulsations could puff in & out near the exhaust tip.

Originally Posted by rspears

Where is your O2 sensor that drives the A/F indicator located in your exhaust? Is it possible that when you stopped at idle you got a "backwash" of ambient air to your sensor, or that you have an exhaust leak that started sucking air as you dropped to idle? The guy who helped with some EFI tuning mentioned to me that the clamp on sensor that he used was good with the revs up, but questionable at idle when exhaust pulsations could puff in & out near the exhaust tip.

The sensor is right past the collector, then to dumps about a foot pasted the sensor.