1jz wont rev past 4k

[s13brian]

Swapped 1jz into my 90' 240sx. Car starts up and idles fine, but will not rev past 4k

only boosting to 6psi
Holds boost up to 4k
Will stay at 4k as long as you hold the gas peddle down

Checked:
both cam sensors, have continuity and signal at the ecu
crank sesnor, has continuity and signal at the ecu
map sensor is reading correct voltage at ecu key on and at idle
opened the ecu up and checked capacitors for leak, I didn't see anything out of the normal
tps is in range at ecu
knock sensors are showing no vibrations

code i have is #12

RPM Signal

Diagnosis
No "NE" or "G" signal to ECU within 2 seconds after engine has been cranked.
Trouble Area
Distributor, or CPS, circuit
Distributor or CPS
Starter signal circuit
ECU

Thoughts? Suggestions? Advice?

 

[Satan]

Replaced the fuel line with a Driftmotion piece and it solved the similar issue with my old 1JZ. May be some restriction in the bends or where it meets the rail. We swapped/troubleshot everything else and that "did the trick." Good luck!

 

[s13brian]

I have a walbro 255 for fuel delivery and am running 3/8ths earl fuel line from the oem hardline to the back of the fuel rail, from the rail to the fuel pressre regulator and back to the return fuel line. Psi at idle and KOER are right where they are suppose to be, so I don't think there is a restriction anyplace.

Thanks for the luck though! I've been at this for weeks!!

 

[Radial]

theese faults are very funny because the symptoms are very confusing, but the error is not always related to the faultcode.

suggest to check your AFR readings, ground resistance for ECU and Sensors ( should be ZERO), check that there is +5v to all sensors if you havent already done it.
defective sparkplugs and cracked coilpacs can also create faults like that, but they are very rare... isolate the coilpacs with shrimps and they are eliminated. Clean the plugs....

 

[s13brian]

My buddy actually figured it out. There was No STA signal to ECU from the starter or something along those lines.

Thanks for the help you guys.