Check engine light shows running lean on bank one,what is te problem?

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Check engine light shows running lean on bank one,what is te problem?

Unread post by Guest » Sun Sep 06, 2020 7:41 pm

Engine running lean on bank one,what is the problem?

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carriedi
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Location: Oregon

Re: Check engine light shows running lean on bank one,what is te problem?

Unread post by carriedi » Mon Sep 07, 2020 4:41 pm

there are things to look at. A vacuum leak on bank one. O2 sensor stuck lean on bank one. Dirty injector(s) on bank one. etc.

Look at bank two fuel trims. Are they getting close to being lean also but not quite as bad as bank one yet? Could be a dirty MAF.

Is there a freeze frame for the code? What is the code's actual number? Freeze frame would help a lot because it will tell you what was happening to the engine when the code was set.

What is the make, model, year and what engine does the vehicle have?

Most of the time, engine codes only give you a direction to look and not what is actually wrong. I remember that back in the day, even dealerships were replacing a lot of oxygen sensors when they got a lean code. Fords especially. The codes would come back in a short time. It wasn't the O2 sensors it was the MAF would get dirty and the dirt would at as insulation so the air flow would show less than actual. The computer sees the MAF number and sends the calibrated fuel but then the O2 sensor would measure the exhaust and see that there isn't enough fuel getting to the mixture. That sets a lean code. And the engine is running lean. Bad info in = bad info out.

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