i have a B20Z with a p75 ecu. the normal redline or fuel cut off is 6700rpms. a little history, engine has 20k miles. ive never had this problem in the 2 years ive had the engine in the car. the car has been stored since november and has been started about 2-4 times a month to keep things going.
i got the car out this weekend for the start of my autox season, in a spirited drive, the engines fuel is cutting off at 5500rpms??? so ive check the oil levels, i disconnected the battery terminal and i unplugged the ECU for about 3 hours. checked the ecu for corrosion when leaving work.. its still cuts off at 5500.
do any of you have any ideas as to what this problem could be? any help is appreciated! thanxx

 

My tachometer lags, I think there is some resistance in my wiring harness of either my engine harness or somewhere on the cabin under the dash but when i redline my engine to 7500 my tach actually lags and reads at 6500rpms. I use Hondata to tune my car and i use my check engine light as my shift light because of how much my tach lags. But this may not be any use of for your kinda of issue however i thought i just throw it out there for you to consider. other possibilities that i can think of would be only a ecu issue like its going into LIMP mode. with the p75 ecu you should be able to take it to 7200rpms before it cuts out.

 

ive never had this problem before, i can tell that the RPM band isnt as "full" as it used to be so i dont believe its the tach. im just hoping its not going into limp mode!!