Mark... thanks for the input man. So did the knock sum go up, timing get retarded AND the injector pulse width go nuts? I want to make sure the injector pulse width went nuts to confirm that it was the MAF signal going erratic that is causing the knock in this case.

On the other hand... how do people get around this with just an AFC??? The AFC would not solve this problem cuz it only manipulates the MAF signal... but won't correct it's erratic behaviour. The only way I can see to solve it is hacking the unmetered section of the MAF to lower the volume and thus velocity of the air going through the metered section. This would bring the velocity down below where the MAF gets overrun. But if an AFC does solve this particular problem then it can't be directly related to MAF overrun Anyone seen this go away after installing and tuning an AFC? In particular did it solve the erratic injector pulse width at 5k rpm or higher? I can see that just richening it up would get rid of the knock but it still wouldn't get rid of the erratic MAF signal.

I put a similar question into the digest... I'll let you know what comes out of it.

Marco... that could be what you witnessed... did you see the knock sum shoot up and the injector pulse width go nuts? Did the timing stay retarded till higher rpms or just freak out at about 4K?

I'm leaning more and more towards MAF overrun here boys as the problem. My mod will get rid of this (what ever the name).... ask anyone I've done it to if they've seen their knock led come on since then

Later....

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Mike Jackson
92 Laser RS-T, FWD
-Quadcylla-
Vortex Racing
http://www3.sympatico.ca/robin.jackson2/HomePage.htm