View Single Post
Old 12-13-2011, 07:30 PM   #8 (permalink)
Cyborg ECU
California98Civic's Avatar
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 5,822

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,174
Thanked 1,875 Times in 1,280 Posts
Originally Posted by jakobnev View Post
Actually, the notion of the ECU undoing your changes is a myth, it couldn't possibly, it doesn't even know you have made any! The reason the car must be put in test engine mode is that it fixes the timing to a certain value, in normal mode the timing might be all over the place, making it impossible to adjust meaningfully with a light.

Well, all I can tell you is what I experienced: if I reset the timing without jumping the ECU, the computer switched it back. If I recall properly, I just about watched the pulley move back to stock timing. But when I jumped the ECU before adjusting the timing, the Ultra Gauge showed still showed no change in timing at warm idle (12* BTDC), but the pulley showed the advance and it stayed advanced. I originally did this process back in May or June, so my memory of the ECU's adjustments might be flawed, but that's what I recall. It was quite frustrating until I figured out the importance of the jump.
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.

  Reply With Quote