A/F Question
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From: Jacksonville , AL
A/F Question
I got my AEM Wideband installed today and had a few questions. First, I dont know very much about A/F ratios. At idle, my gauge is reading 14.6-15.1. At cruising RPMs, whether it be 25 or 90, the gauge is between 14.3 and about 15.3. When I stomp on it hard, it drops down in the 11s and 12s. Could someone who is very knowledgeable about AFR tell me exactly what these mean and if these readings are bad/good? Thanks in advance.
Zach
Zach
Your reading are normal. At cruise, minor part throttle, or idle, your AF should be near 14.7:1...slightly higher or slighty lower is fine, becuase it tends to bounce around a bit. Under these conditions, the ECU is reading your 02 sensor readings and trying to maintain stoich conditions.
When you go WOT, the ECU disregards the 02 readings, and adds fuel based on MAF sensor inputs. So when you floor it, the ECU see more air, and adds way more fuel. If you are in the 11- 12's under WOT for an N/A car..that is a bit rich...but not too bad.
Ideally in an N/A car, people are shooting for high 12's to 13:1, and F/I cars are shooting for 11.5:1 for safety.
All and all...you look OK!
When you go WOT, the ECU disregards the 02 readings, and adds fuel based on MAF sensor inputs. So when you floor it, the ECU see more air, and adds way more fuel. If you are in the 11- 12's under WOT for an N/A car..that is a bit rich...but not too bad.
Ideally in an N/A car, people are shooting for high 12's to 13:1, and F/I cars are shooting for 11.5:1 for safety.
All and all...you look OK!
Thread Starter
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iTrader: (23)
Joined: Jan 2004
Posts: 2,259
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From: Jacksonville , AL
Originally posted by gq_626
Your reading are normal. At cruise, minor part throttle, or idle, your AF should be near 14.7:1...slightly higher or slighty lower is fine, becuase it tends to bounce around a bit. Under these conditions, the ECU is reading your 02 sensor readings and trying to maintain stoich conditions.
When you go WOT, the ECU disregards the 02 readings, and adds fuel based on MAF sensor inputs. So when you floor it, the ECU see more air, and adds way more fuel. If you are in the 11- 12's under WOT for an N/A car..that is a bit rich...but not too bad.
Ideally in an N/A car, people are shooting for high 12's to 13:1, and F/I cars are shooting for 11.5:1 for safety.
All and all...you look OK!
Your reading are normal. At cruise, minor part throttle, or idle, your AF should be near 14.7:1...slightly higher or slighty lower is fine, becuase it tends to bounce around a bit. Under these conditions, the ECU is reading your 02 sensor readings and trying to maintain stoich conditions.
When you go WOT, the ECU disregards the 02 readings, and adds fuel based on MAF sensor inputs. So when you floor it, the ECU see more air, and adds way more fuel. If you are in the 11- 12's under WOT for an N/A car..that is a bit rich...but not too bad.
Ideally in an N/A car, people are shooting for high 12's to 13:1, and F/I cars are shooting for 11.5:1 for safety.
All and all...you look OK!
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