jeb99ta

In Neutral or in Park, the ECU will shut the fuel off at about 4000 rpm.

Playing around with manual select shift, I hit 7000+ RPM for a brief second while switching back to normal auto mode. Thinking the switch had occurred, I accelerated too soon and hit the pedal pretty hard and nothing happened and I thought there was a mechanical problem. I hit the pedal pretty hard again thinking it was in gear and there went the needle ... BAM ... all the way to the wall. I then let off and allowed the shift to occur and everything seems to be fine.

Anyone ever have this happen?

engineermike

The ECM has at least a couple of different rev limiters. The 4000 rpm neutral limiter is done using the ETC, not fuel shutoff. Unless 5-Star screwed up royally (I doubt they did), there will still be a hard limit up high regardless of shift mode.

jeb99ta

Thanks for weighing in Mike. I've taken it to the track and raced it a dozen times without issues. Under load, it would not transfer back to Automatic from manual select shift. That's when it occurred. Why would it hit 7000+ rpm ? I'll take it back out to see if I can replicate it ... just not all the way up to 700+.

Anyone know?

mechanicboy

That is weird. I know that in P or N I can hit 6800rpm and I've hit it a time or two in the shift between 1st and 2nd because the shift came late. This usually happens because it had downshifted to 1st at wot. I am going to raise the rev limiter so it won't happen again. The guys in the mustangs spin these engine to almost 8k so I wouldn't worry about the rpm I would only be worried if you had a trans or ecu shifting problem.