Can't rev over 6k
05-05-2012, 08:02 PM
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Can't rev over 6k
This isn't on a miata, but I figured there are enough MS users on here that perhaps a solution will fall out 
.
Car:
240SX w/ KA24DE swap.
Turbocharged, running MS2extra 3.1.0.
Single coil, stock cam sensor providing trigger input.
Nothing fancy, just a pretty much 'by the book' MS2 build w/ EBC.
The problem:
The damn thing won't rev over 6k under load. It pulls fine under any amount of boost, but around 5500 it starts to slow down, and hits a wall at right about 6k. Free revving doesn't exhibit this issue.
On the dyno, the onboard WB sensor goes full rich when this happens. Tried leaning it out, the result was knock and a severe lean spike (in other words, it didn't smooth out, it was one extreme or the other).
Things I've checked:
Fuel pressure is good.
Fuel injectors are 560cc subaru injectors and have been recently cleaned.
Tried swapping coils (MSD Blaster SS and stock)
Changed plugs and re-gapped to .028
Swapped wires.
Swapped distributor.
Checked base timing.
Tried dwell from 2.5-4.5ms
Things that confuse me:
The WB on the dyno read full rich when this happened. I thought that perhaps the injectors were going static early and pissing fuel.
Checking the duty cycle shows ~60% at 6k and the AEM WB reads fairly rich(~10.9) with big jagged peaks. Before this it was at 11.1-11.5:1.
Duty cycle seems a bit high to me for 5psi.
So, Bros. Any ideas? I'm attaching a recent .MSQ and a few logs. Lets touch tips and figure this out .
.Car:
240SX w/ KA24DE swap.
Turbocharged, running MS2extra 3.1.0.
Single coil, stock cam sensor providing trigger input.
Nothing fancy, just a pretty much 'by the book' MS2 build w/ EBC.
The problem:
The damn thing won't rev over 6k under load. It pulls fine under any amount of boost, but around 5500 it starts to slow down, and hits a wall at right about 6k. Free revving doesn't exhibit this issue.
On the dyno, the onboard WB sensor goes full rich when this happens. Tried leaning it out, the result was knock and a severe lean spike (in other words, it didn't smooth out, it was one extreme or the other).
Things I've checked:
Fuel pressure is good.
Fuel injectors are 560cc subaru injectors and have been recently cleaned.
Tried swapping coils (MSD Blaster SS and stock)
Changed plugs and re-gapped to .028
Swapped wires.
Swapped distributor.
Checked base timing.
Tried dwell from 2.5-4.5ms
Things that confuse me:
The WB on the dyno read full rich when this happened. I thought that perhaps the injectors were going static early and pissing fuel.
Checking the duty cycle shows ~60% at 6k and the AEM WB reads fairly rich(~10.9) with big jagged peaks. Before this it was at 11.1-11.5:1.
Duty cycle seems a bit high to me for 5psi.
So, Bros. Any ideas? I'm attaching a recent .MSQ and a few logs. Lets touch tips and figure this out .
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