my VTCs have recently started to tick at start-ups ("oh crap"). could be due to the cold weather. after some thinking and reading the FSM i decided to wire a switch to ground/unground the VTC from behind the driver seat (grounded the VTCs right from the ECM not under the hood per Craig's directions). i'll ground the VTCs at start-ups, get the oil pressure up, then unground them when the engine is warm... no more ticking. i know this is not a new concept.... but i also wired an LED to the switch to see when the VTCs are engaging/grounded. when the VTCs are grounded the LED lights up. pretty cool findings. the "belief" on the org seems to be that the VTCs "engage" after ~3.2k rpm. i found that the VTCs are actually grounded when the engine is under load (like the FSM says) from any gear at any rpm. if you stomp on the gas the VTCs will be grounded (even 5th). after climbing up the tach and engine load is less, the VTC becomes ungrounded... makes sense. to test this i accelerated from a stop to see what the VTC's were doing. from a stop and launching hard the VTCs were grounded up until about 3.5k, shifted to 2nd close to redline and the VTCs were grounded again until about the same RPM. that is the extent of my testing this weekend.

 

VTC receive oil when at low rpms, keeping them in the retarded state. When conditions are right, they turn off(grounded?) and the intake cam advances 8 degrees or so.

I think this is a little different than my write up on the subject 2 years ago

 

that is awesome on the led thingy, howd u wire it up? i wanna do that...maybe i could put in where the extra space is on our dash? itd b like vtec stuff, but gayer cause ours malfunctions n crap...lol

keep us posted on what your findings r in the long run, like if it helps, etc

 

Good job and info!

Now, who is going to be the first to come out with a "VTC Controller"?

 

At idle they are off (ungrounded, no oil). when your drive normal they are on (grounded, oil press is applied), up until 3.2K rpm (I thought the manuel said 4.2k rpm) where they turn off (ungrounded) and the engine gets its natural torque peak which is greatest.

 

Why would the cams be "off" at idle? "off" "on" "off" doesn't make sense to me.

 

Yup they are off, its in the FSM. I had intentions of scanning the pages but I've been a little busy (or lazy). When we 'ground' the VTCS it turns them on (completing the circuit) and engaging the sproket.

Thats why they clatter they are just floating there and the spring is'nt strong enough the fully disengage them. It may be a combination of the spring not being strong enough and sludge/varnish giving enough resistance/surface tesnion for the VTC to disengage.

Thats why I was giving advice to run a motor flush. But then finding that oil does not circulate when at idle, the oil flush will not clean the galley or VTC, UNLESS they are grounded during the flush!!

 

have you gorunded them while running the flush, or has ne1 else? ive got about 1k until my next oil change, i just dont wanna b the 1st 2 do this...mine work and i wanna keep it that way

 

I'll be doing it soon