short term fuel trims reading high
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From: florida
short term fuel trims reading high
my trims from evosan in the low load read around 125 to 135, mid and high stay around 100, ive been told that the evoscan fueltrims are off, ive also been told that the positive fuel trims wont affect my a/f while at wot as well even know that on other cars i know it does, any adivise on changing the trims closer to 100 or should i not worry about it?
Thread Starter
Newbie
Joined: Jun 2006
Posts: 87
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From: florida
car cruises and idles around 14.9 to 14.7, it runs fine but the fuel trims are alway around 125 to 135 on the evoscan in the low trims, acording to evoscan it reads to 200 which is probally +25 percent so im guessing 130 is around 6 percent fuel be added
Thats roughly correct.. If its indicating the trims are +xx% then you add fuel, -xx% you remove fuel..
Only the closed loop fueling is a little counterintuitive, so it takes a little trial and error.. Generally trims are the difference in the desired fueling from the background map (open loop map at low load) and the ECU's attempt to maintain 14.7
For instance, if you disconnected the O2 sensor, the fuel adjustments you would make to get it back to 14.7:1 would result in a 0% (or 100% on Evoscan) fuel trim requiring very little work from the ECU to maintain it when you reconnect the O2 sensor.
Only the closed loop fueling is a little counterintuitive, so it takes a little trial and error.. Generally trims are the difference in the desired fueling from the background map (open loop map at low load) and the ECU's attempt to maintain 14.7
For instance, if you disconnected the O2 sensor, the fuel adjustments you would make to get it back to 14.7:1 would result in a 0% (or 100% on Evoscan) fuel trim requiring very little work from the ECU to maintain it when you reconnect the O2 sensor.
Thread Starter
Newbie
Joined: Jun 2006
Posts: 87
Likes: 0
From: florida
Originally Posted by MalibuJack
Thats roughly correct.. If its indicating the trims are +xx% then you add fuel, -xx% you remove fuel..
Only the closed loop fueling is a little counterintuitive, so it takes a little trial and error.. Generally trims are the difference in the desired fueling from the background map (open loop map at low load) and the ECU's attempt to maintain 14.7
For instance, if you disconnected the O2 sensor, the fuel adjustments you would make to get it back to 14.7:1 would result in a 0% (or 100% on Evoscan) fuel trim requiring very little work from the ECU to maintain it when you reconnect the O2 sensor.
Only the closed loop fueling is a little counterintuitive, so it takes a little trial and error.. Generally trims are the difference in the desired fueling from the background map (open loop map at low load) and the ECU's attempt to maintain 14.7
For instance, if you disconnected the O2 sensor, the fuel adjustments you would make to get it back to 14.7:1 would result in a 0% (or 100% on Evoscan) fuel trim requiring very little work from the ECU to maintain it when you reconnect the O2 sensor.
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