I'm no noob to diagnosing Hondas or motors or anything but this issue has me stumped. The motor is a b20v gsr head whatever. Its been running in my car since April with 0 problems. The other night, i had it out for a drive and vtec just wouldn't work. I noticed it coming out of a hard turn, so i figured that my oil might have been low or something even though it worked fine earlier that night. Level was good. So here is the point im at. Ive tested/done the following:

-replaced solenoid screen and made sure plunger/pin in solenoid was free
-12v to solenoid, it clicks
-wire from solenoid into car ohm'd out
-removed oil supply line to head and blew out with air blower onto a shop towel. checked for debris, nothing.
-Hondata DOES switch to the high cam map

I have not touched this motor internally since October or so. So that eliminated forgetting an orifice or something of that nature.


So I've only got a few options at this point. Check overall oil pressure(doubt it), pull t fitting off back of block and check for blockage, check for 12v coming from ecu at vtec engagement, or drive it off a cliff.

Let me know if you could think of anything else that it might be.

UPDATE #1
The car does have 13.3-13.4 volts from ecu when vtec kicks/was supposed to. So that eliminates ecu.

UPDATE#2
- Removed factory pressure sensor and hooked up gauge. reads about 25-30 psi at idle. Sounds about right considering i have pro1's and a small vac leak i found today. I know that could be the issue in some cases, but hondata still switches maps so i dont think so.

- Hooked up gauge to port right in front of the vtec solenoid. The manual says it should read below 7psi at idle. Mine reads 0 at idle. It then says to rev the car to 5k and jump a wire between the battery terminal and the solenoid. The gause should read 57psi IIRC mine still reads 0.

- Removed solenoid and bench tested it. Checked out good.

- While solenoid was off, I removed the oil supply fitting in the back of the head and fed a zip tie through to make sure there were no blockages. Nothing.

- Hooked it all back up and bypassed the vtec wire in the wiring harness. Even though this wire ohmed out I still ran a test lead to the solenoid. Still nothing.

Im stumped. Even if there were not enough pressure/a blockage, shouldn't that port next to the solenoid get some sort of reading when the solenoid is forced to open?

 

I basically pasted this all over from my thread in the tech section, which I was getting nowhere with. If you have some silly thing you heard happened to your cousins sisters boyfriends brother or something let me know. I've done all the tests in the honda manual, helms manual, spoken with a few other techs, and still have nothing.

 

have you replaced the solenoid? checked the ground for the vtec to make sure it didn't break off or anything? I had the same problem on my car and never figured it out, it ended up blowing the rings and I built my LS/Vtec engine.

 

Yes i replaced it even though it tested to be good. And there is no ground wire for the solenoid. It grounds to the engine.

 

actually there is a ground wire for the vtec pressure switch. that's what I was referring to.

 

I do not have a pressure switch. I have hondata and it is disabled. bump anyways

 

oh ok

 

what about an orifice in the head?

 

sounds like you already found the problem, no oil pressure up to valve train, check wat ever the oil supply is up to the solenoid for restrictions and rtv or some other gunk. i've personally never built a ls-v or b20-v, but you do need oil pressure up to the solenoid to work. just my 2 cents

 

there is oil pressure at the t where the line feeds up to the head, and if you crack the line loose at the head, it has pressure. The entire external oil feed is free of anything. I think pressure may be entering the rockers to lock them in, but a leak/blown o-ring in an orifice would cause the rockers to loose the pressure needed to lock vtec in.

 

Do you have any more updates on anything you've tried since then? My friend's vtec is also not working and I rode shotgun with a test light (no multimeter, so I don't know the voltage) and probing A4 on his p28 it is sending the signal to his solenoid. I know all the wiring is correct because we unplugged both the pressure switch and the solenoid indivudially to get a CEL. No other codes. Speedo works... I haven't had a chance had a chance to completly remove the vtec assy form the head, but I did remove the solenoid top half. The port had burnt oil on it because (I think) the plunger on the the assy was pointed 180 degres off from the direction of flow from the solenoid.The oil wasn't being directed into the hole in the plunger..that didn't fix it either. He just replaced his headgasket by himself...maybe he forget the o-ring on the oriffice...