P0171 System too Lean Bank 1 is the code I.

Tiny
TICKETIN
  • 2001 TOYOTA CELICA
  • 208,000 MILES

P0171 – System too Lean (Bank 1) is the code I get from the check engine light. I do not know what is causing this code. It used to come on when my fuel level went below a quarter of a tank. Now it comes on after driving about 230 miles. Someone told me the light comes on because the fuel today has more octane then when my car was built. Is this true? What are possible causes or solutions to fix this.
I purchased this car new and have been the only owner. I have kept up regular maintenance of the vehicle, the check engine light is the only issue I have with the vehicle.

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Monday, March 4th, 2013 AT 1:52 AM

7 Replies

Tiny
SATURNTECH9
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So what octane fuel do you use?Also would check actual fuel pressure and look for vacuum leaks because its setting a lean code. Also actually fuel octane back in the day was higher then it is now. Some of the older cars needed the higher octane fuel because the compression ratios were higher then they are today.

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Monday, March 4th, 2013 AT 2:08 AM
Tiny
TICKETIN
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I use 87 octane fuel. I have checked for vacuum leaks, but will check again. Could the increase in the precentage of alcohol in fuel be causing this?

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Monday, March 4th, 2013 AT 2:19 AM
Tiny
SATURNTECH9
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No increased alcohol just eats seals orings etc. How did you check for vacuum leaks?The best way to check for vacuum leaks is with smoke.

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Monday, March 4th, 2013 AT 6:41 AM
Tiny
TICKETIN
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How do you check for leaks with smoke?

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Tuesday, March 5th, 2013 AT 12:57 AM
Tiny
SATURNTECH9
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You can make a smoke machine or try using a cigar and blow smoke into the brake booster vacuum line. You have to plug off the throttle body.

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Tuesday, March 5th, 2013 AT 4:49 AM
Tiny
TICKETIN
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Thanks, I, m going to try that.

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Thursday, March 7th, 2013 AT 12:58 AM
Tiny
SATURNTECH9
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Your welcome keep me posted.

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Thursday, March 7th, 2013 AT 2:35 AM

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