What's going on here? A friend just put a STOCK H22A1 in his Prelude VTEC.

i.e. this is a plug and play engine, stock OBDII P13 ECU and everything. Post install he can only rev to 6500 rpms. Normally I would say this is limp mode, but there is no code, and VTEC still works. Well up to 6500 rpms, then it hits a fuel cut/rev limit. Any ideas? Everything worked fine on the car it was previously on...

 

could be a lot of things if the motor isnt full warmed up, u might have a code and not know it... CEL is burned out... CEL driver on the ECU could be bad. check the wires on the VSS. What year ecu do u have. Vss could be bad but that would throw a light.

 

Warmed up no code; Had CELs with previous ECU so light works, ECU CEL driver could be bad....

VSS was replaced....we broke off the VSS mounting piece when removing the engine, so we grabbed one off a 93 VTEC and attached the Power Steering lines. The wiring could be bad? Hmm If we unplug the VSS we should get a light right? I'm guessing that's how I could test it.

 

WAIT A MINUTE.....we found that on one of the VSS that the gear wheel was bigger than the other VSS we had...it was the one on the car that the engine came from. These are all H22A1s but the gears were different.

So it's possible the gear in the engine right now is too small and is not spinning....hmmmmmm I have to check this out. We were wondering why it was like that. So bizarre

 

out of curiosity, what *should* it rev to before cut off?

 

7800 rpms on a stock p13 ecu. 6500 is a limp mode characteristic.