Long story short, I'm trying to figure out why my VTEC isn't working and i'm sure that it isn't an electrical problem. I have verified the electrical signal is getting to the solenoid and I have verified the solenoid screen is clean and it is clicking when I give it voltage.

I have my air compressor hooked up to the port on the front of the engine to the left of the manifold w/ 55psi and a friend and I are plugging all the holes we think are losing air, but VTEC doesn't seem to engage; none of the pins lock with the lobes. I see air bubles around the pins and the pins move ever so slightly. The cams are out of the motor, so when I pressurize the oil system I can lift the VTEC rocker up and down and it never locks up with the others. The pins are moving freely. Is there some trick to this? Shouldn't I be able to pressurize the system to 55psi and play with the VTEC lobe and have it lock together? I can tell a little air pressure is seeping out, but it seems mostly pressurized to me. Is there some other special hole somewhere?


Maybe i'm doing something wrong with the air pressure test so any feedback would be greatly appreciated.

 

You have to have the cams and cam caps on and torqued to specs for this method to be done
-set your valve lash clearances to spec
-make sure you check each rocker arm at TDC
-you need to cover the relief hole by the vtec solenoid, its a special tool honda sells
-put a air regulator and set it between 36-71 psi until the pin locks
-push on the mid lobe it should not move at all, if it doesnt then it means its working properly.

if any of them does move, then you have debris or a bad pin etc

what engine and ecu you running?

 

Thanks onepiont6i!!! VERY Helpful!!!

I'm running a LSVTEC (b18b/b18c1 head) w/ a p28 ECU. For testing purposes I've ran a switch straight from the battery to the VTEC solenoid, so i'm pretty positive it's mechanical.

I had not verified valve lash or put each rocker arm at TDC. I did not go up as high as 71PSI (I stopped at 55psi).

Maybe this will help me understand VTEC (the problem) better, why does each rocker need to be at TDC to be tested? Is that the only time VTEC can actually engage?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cyphear &raquo;</TD></TR><TR><TD CLASS="quote">
Maybe this will help me understand VTEC (the problem) better, why does each rocker need to be at TDC to be tested? Is that the only time VTEC can actually engage?</TD></TR></TABLE>

Because if all 3 rockers aren't inline with each other, the pins can't engage the center (VTEC) rocker. So yes, only when the rockers are not open, will VTEC be able to engage.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mikey3000 &raquo;</TD></TR><TR><TD CLASS="quote">

Because if all 3 rockers aren't inline with each other, the pins can't engage the center (VTEC) rocker. So yes, only when the rockers are not open, will VTEC be able to engage.</TD></TR></TABLE>

Awesome, that makes sense. I guess I understood that, I was just making sure that there wasn't something that's special about being exactly at TDC.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by onepoint6i &raquo;</TD></TR><TR><TD CLASS="quote">You have to have the cams and cam caps on and torqued to specs for this method to be done
-set your valve lash clearances to spec</TD></TR></TABLE>

I just spent a few hours with it, but i still can't figure it out. I have the cams out of the motor and i have the cam caps tightened (maybe 3 lbft), but i didnt tighten them to spec. Does that make a difference? I hear and feel air coming out of the bottom of the camshaft covers (the little holes). Is that normal? I'm assuming valve lash doesn't matter since the cams are out of the motor.

If I lift the lobes up with my finger it'll shoot out the pins, but if I have them all inline it just wont compress the "receiving" pin. So it's like there is a tiny bit of pressure but not much.

To sum up: Do the cams need to be in the motor? Do the cam caps need to be at spec, not just tightened lightly? Is it normal to hear air coming out of the camshaft covers?

Thanks!!!

 

i had a friends car that had the exact same problem. it ended up being that he had a small *** 3an oil line off the block to a tee with an oil pressure gauge, stock sender and head line ran off that. soon as i put the 6an line right on the block vtec worked perfect

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b20vtechb &raquo;</TD></TR><TR><TD CLASS="quote">i had a friends car that had the exact same problem. it ended up being that he had a small *** 3an oil line off the block to a tee with an oil pressure gauge, stock sender and head line ran off that. soon as i put the 6an line right on the block vtec worked perfect</TD></TR></TABLE>

Thanks. At some point I'll put this back together and buy a gauge and measure the oil pressure.