Smacking sound coming from the valve cover when in vtec..i do not have vtec. Did the test and everything checks out good with the electrical aspect of the vtec. Any ideas???

 

Lack of oil pressure? Throw a gauge on and go for a drive.

 

Oil pressure is good??? 20 psi at idle 87 at 3000 rpm.

 

What causes oil pressure problems????

 

Lack of oil pressure will prevent vtec from engaging because the solenoid works off pressure. So, it could either be low pressure, or dying solenoid.

Low pressure can come from a number of things..

#1 is worn rod bearings. Low pressure from this is an early sign of future issues.. fix or you may eventually spin a bearing, which is very bad.
low oil level (pump can't pick up enough oil)
dying oil pump
clogged oil passage, line, or valve (oil filter should have a bypass if it gets clogged)

 

But what is the smacking sound coming from the head when vtec is engaged????? Still no vtec but after 6 thousand rpm there is a loud smacking sound coming from the top of the motor..

 

You really need to take a look under the valve cover to see what's going on. Just curious, but moving down the road with the engine turning 6k rpm, how do you know the sound is coming from the valve cover area?

 

There is also an oil temp limit for Vtec. I am sure you warmed up the car first. I wonder if that sensor can fail. Have not heard of it, but it may be worth to check out.

 

So hooked up a computer and activated vtec and it engages but there is horrible banging slash smacking sound coming from the head.. Was testing it in a garage ??? Any ideas. I already looked under the valve cover nothing looks outta place turned the rollers none cracked tested the rockers everything is good .every thing moves as it should.

 

Maybe you have way too much valve lash (valves too tight), which can cause noise that is accentuated at higher rpm. Did you do a valve adjustment, or check the valve clearances when you were in there?