No announcement yet.

Aloha! VERY lean low RPM, heavy load/ 17:1 on my AFR gauge..any ideas?

  • Filter
  • Time
  • Show
Clear All
new posts

  • Aloha! VERY lean low RPM, heavy load/ 17:1 on my AFR gauge..any ideas?

    So, here's the situation. While climbing a long hill...or even on a flat straight....if I'm at 2500-3000rpm in a higher gear and I accelerate the car to put it in a low rpm "boost" scenario, it gets scary lean (17-ish:1) and stays there.....until I lift.
    If I'm accelerating briskly from a stop and rowing through gears, AFR is 11-12:1 ish like I'm assuming it should be.
    Any ideas?

  • #2
    For what it's worth, I'm having the same issue. I'll let you know if I find a solution. After checking all the vacuum lines, the bypass actuator and the boost reference line, I am now onto changing the fuel pump.


    • #3
      No luck with the fuel pump. On to checking vacuum lines again.


      • #4
        Any progress? I'm still at a loss.


        • #5
          Still diagnosing .
          stay tuned


          • #6
            So I double checked the tuning cards which the installer coiled and placed inside the area under the steering wheel. What I discovered seemed to fix my problem.
            1. the boost reference line where it goes from small tubing to larger clear tubing and attaches to the sensor….the clear tubing is so soft it actually folded and I’m sure was giving an inaccurate reading.
            2. the settings on my boost fuel card were lean on the green-blue setting. So I bumped it up a notch.
            3. I also found a vacuum leak at the EGR valve.
            4. ALL of the large 3/8”(10mm) vacuum hoses are WAY, WAY too soft and easily collaps. There is no way these hoses are vacuum rated. I had to replace several hoses related to the Vacuum hoses on the intake side of the motor.

            Im now getting a 11:1 AFR at low rpm/high load situation….it gradually comes up to 12-12.5:1 as revs increase.

            I have an autocross this weekend….I’ll update.


            • #7
              Thanks for reporting back. Still in progress on my issue. Let us know how the autox goes.


              • #8
                AutoX is great ! Now tires are the weak link…not motor..

                Having new issues with the damn cards…..
                Now at full throttle rowing through the gears AFR goes to 10:1
                High load, 3-4k rpm full throttle and AFR has a mind of its own.
                Sometimes it’s 10:1, other times it’s 11:1 others it’s 14:1 and SOMETIMES power drops instantly and the AFR is 18:1 !

                Super frustrated.

                Main issue is I have to do a sea level to 8k foot climb and back down to sea level to get to the track on the other side of the island…… super lean/rich AFR is bad.

                Not sure what is going to make these dang cards more consistent…?