Nissanman, Hi. Sounds like you might have got a boost spike and/or excessive load detection, your ECU detected the resulting detonation, retarded the ignition and shut off the boost, effectively killing the power.
You were on a gradient at relatively low engine speed, in a relatively high gear and only just coming on-song at ~2700 (= 84kmh in 5th) with rapidly rising turbo spindle speed, so you have a fair amount of load on, even with light throttle application.
These engines have such a flat torque curve and pull like there is no tomorrow from low engine speeds so that one is often tempted to pull from fairly low speeds in the upper gears. I generally use quite high gears as long as no load is on, especially on downgrades, mainly for the peace and quiet and economy, but change down if I need to pull harder and make sure the engine is spinning freely. I'm not suggesting one needs to cane the car mercilessly, but be very aware of loadings at low rpm.
However, as I have been discussing off-line with MattMPS3, sometimes the engines perform better with higher rpm as they seem more capable of usefully and more smoothly ingesting all the boost generated when the engine is well and truly spooled up, say above 3,000rpm anyway.
This is of interest as applying particularly to my car where the mods have added a heap of readily available boost and pussyfooting around in higher gears at low engine speed creates more boost and boost dump problems than using a few more revs.
It will be interesting to see what you and Mazda come up with.
BTW, I doubt your detached earth lead will have had much effect on the issue at hand, although plainly it helps to have it connected. Your red circle does show the correct connection location on the engine mount, too.
Last edited by Doug_MPS6; 02-02-2010 at 04:07 PM.
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