flashing the ecu 2001 qx4

[johnpaulson]

I HAVE A 2001 QX4 WITH A NEW OVERHAULED MOTOR WHEN I AM GOING UP A HILL UNDER A LOAD IT WILL SOMETIMES PINGING NOISE IN THE ENGINE I USE 91 OCTAINE FUEL?

[asnorton44]

Did you just start using 91 octane? I know the 2001 engine is a high compression engine and that it was tuned to use 91 octane - but I have always used 87 although ive noticed a ping before.

[Chuck Tribolet]

It will take a couple of tanks for the ECU to learn. I would do whatever check is in the FSM for the knock sensor.

91 octane is speced, the knock sensor and ECU should get things adjusted even if you are on 87 octane.

Chuck

[Towncivilian]

It will take a couple of tanks for the ECU to learn. I would do whatever check is in the FSM for the knock sensor.

91 octane is speced, the knock sensor and ECU should get things adjusted even if you are on 87 octane.

Chuck

I don't think it takes any time at all. I have been using 89 octane and am happy with the performance increase compared to 87 while still saving a few bucks compared to 93 (91 is typically not available in Florida). I tried 87 a couple of tanks ago and man was it slow, I noticed the difference right as I pulled out of the gas station.