hey whats up guys!! I recently swapped my em1 with a b18 84 mm stroked, but kind of have some problems whit vtec . well v tec wont kick when hot and it does when cold.
what do you think could be the problem?? already change vtec oil pressure switch...
thanks for your help .....

 

I'm pretty sure VTEC isn't even supposed to work until the engine is warmed up

 

Low oil pressure will do that. The VTEC system depends on oil pressure from the oil pump to work properly. If the pressure is too low after the VTEC solenoid opens, it won't trip the pressure switch like it should. The ECU detects that and will throw a CEL and disable VTEC for the rest of the drive.

Oil thins out when it gets hot and if for example the main bearings are worn, the oil pressure can drop below the acceptable level.

 

How cold is cold it shouldnt kick in till the engine has warmed up some where is the collant needle on the cluster at when you say cold