vtec not working

Damn I got an infraction for that post! :(

re-check all wiring. If thats all ok, then check engine. Do comp test.

why o2 sensor ?? oil levels are fine an so is pressure, i put power to vtec sol an it clicks so the solenoid is ok, other than any of this it could really only be to do with wiring ay ?

Quote:

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Originally Posted by nick_sixx

o2 sensor?

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i dunno i read it in autosalon in the forum bit haha. some guy had an h22a civic with no vtec so they told him to go buy an o2 sensor :D

Quote:

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Originally Posted by mclovin

is your tach working?? check that too as the same happened to me. i converted my ef to have b18c also. one day vtec worky, the next it didnt. i realised that my tacho didnt work then noticed that vtec wasnt engaging.

vtec needs rpm signal to engage, on top of whats already been mentioned.

hope that helps mate.

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are you sure? because my sohc vtec still works and i broke the shit out of my tacho, and am only using an aftermarket one currently

just cause your tacho is broke doest mean rpm signal isnt getting to ecu.
sorry should have put it differently.

my tacho cable broke in my ef so wasnt getting reading for tacho or ecu.

check wiring for rpm signal, from my experience the wire should be purple, remove your gauge cluster and disconnect the connector from it, put a volt meter on the purple wire, start the car and rev the engine. watch the volt meter, if the voltage fluctuates then its fine if not you will have to trace the wiring to find the fault.

i also doubt that it would be the 02 sensor as this has nothing to do with vtec operation. the job of the 02 sensor is to maintain near perfect air fuel ratios.


if you want another suggestion, check if your coolant temp sensor is working properly as vtec requires the car to be at normal operating temps. if it is sending a faulse signal to your ecu ( engine still cold when it isnt ) then this would also stop vtec operation. find out what resistance it should have and compare with the one that is in your car.

hope that helps a bit more.