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Old 10-24-2020, 06:14 PM   #1
Trob
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Default Air/Fuel Ratio

Left with no ideas on this one. Just put built motor and heads in a 2011 Wrx. After putting motor back in start the car ran fine for five minutes. Took it for a drive and at every stop it stalls. Check AP and the air/fuel is stuck at zero. Checked wires going to mass air flow all is good.

So the car runs at zero no matter where engine rpm’s are. I’m stuck in this one any help would be appreciated!
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Old 10-24-2020, 07:56 PM   #2
Psychoreo
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Your MAF doesn't measure your air fuel ratio.
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Old 10-24-2020, 08:27 PM   #3
Trob
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Sorry arf learn 1 is at zero and will stall out if you come to a stop. I got it to move to 3.9 when cruising but drop to zero at stop and kills motor.
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Old 10-24-2020, 11:02 PM   #4
Trob
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Anyone have an idea?
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Old 10-25-2020, 02:24 AM   #5
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Quote:
Originally Posted by Psychoreo View Post
Your MAF doesn't measure your air fuel ratio.
You maf sensor measures air mass, the ecu then uses the measurement to calculate how much fuel to inject per given load/rpm cell in the fuel map. So if there are any issues with the maf then it will directly affect the air/fuel ratio.
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Old 10-25-2020, 02:25 AM   #6
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Quote:
Originally Posted by Trob View Post
Anyone have an idea?
Do you have a wideband? Fuel trim at zero could just mean the ecu hasn’t switched to running closed loop fueling yet.
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Old 10-25-2020, 05:20 PM   #7
Trob
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I do have a wideband and numbers are normal. I just ran the car for a bit and moved idle up a bit. It no runs fine and will idle at stops.

I believe you were right with it not being in closed loop. After driving for a bit it is fine.
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Old 10-27-2020, 10:38 AM   #8
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Quote:
Originally Posted by alexmartynyuk View Post
You maf sensor measures air mass, the ecu then uses the measurement to calculate how much fuel to inject per given load/rpm cell in the fuel map. So if there are any issues with the maf then it will directly affect the air/fuel ratio.
Yep, except
Quote:
Check AP and the air/fuel is stuck at zero. Checked wires going to mass air flow all is good.
These are unrelated. The AP doesn't measure the AFR from the MAF.
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Old 10-30-2020, 07:05 PM   #9
Trob
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It read air/fuel learning one witch is what I’m talking about.
All fixed anyway
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