hahnn002

I installed Kank Vents on my NA car, the turbo is going on next weekend if I don't get shipped out again, and they deffinitely make a vacuum in the crank case. I pulled the dipstick out while the car was running and heard a loud hiss of air rush back in, and it wanted to suck the dipstick back into its hole. For those that don't know what Krank vents are look in the Forced Induction thread on the first page.

However, I can't VTEC anymore. I drove just before putting them on and it was good, and drove just after and no VTEC. Pulled them off and still no VTEC. There is no check engine light on, and the oil level is just below the "H". The car will keep reving to around 8500 and then will bog down and I let off the gas. Thats not redline but it's also above the cold engine cutoff, and yes my engine was warmed up. I can't hear or feel the VTEC kick in, and with my loud ass intake I always hear it. I dont think the Krank Vents would cause this, and I hope it was just a coincidence that my VTEC problem started at the same time.

My oil is clean and I would think a malfunctioning solenoid would cause a CEL, but I'm going to pull the solenoid anyway and check its filter. Then I'll test the solenoid for proper operation with an adjustable DC power supply on my workbench, watching to see if it clicks over when I give it some power. Other than the solenoid maybe being bad anybody have some input? Also, anybody have what the resistance readings are supposed to be across the two solenoid pins? It's in the service manual in section 6, but I don't have one right now. My car is a MY00.

-Nate

Slows2k

It's impossible for the VTEC to not work and you not have a CEL. If the Solenoid or pressure switch was faulty the CEL would be on, and you wouldn't have any revs over approx 5k.


EDIT: It's electrically impossible, unless you have a Malfunctioning PCM. (which is quite rare and usually won't even run the engine)

darkfx

If the oil pressure isn't within a certain range then VTEC won't work

hahnn002

Slows2k,

It is certainly not impossible because that is the status of my car, although I thought so too until now. I am not brand new to working on cars or the S2000 but I am no mechanic.

I just got out of my car a few minutes ago, the following are FACTS on my car right now:

1. My VTEC does not engage, not even trying. The rpms keep climbing and nothing changes. I expect the cold limit cut to hit, even thought the engine has been warming for 20 minutes, and it doesn't. The rpms keep climbing to 8500, my redline is at 9000, and then it gets a little louder and kind of starts to bog. I basically can't redline and I don't push it any harder at that point and let off the gas. When VTEC normally kicks in it sounds like it's being broadcast through a loudspeaker with my HKS intake, and I was driving under a highway where it normally echos like crazy, but right now there is no change in engine sound.

2. I do not have a CEL. The light is not lit and it is not burned out. I induced a CEL on purpose by driving with the speed sensor disconnected just to make certain that it works.

Any other ideas?

hahnn002

Exactly, which is one reason I want to check for gunk in the oil filter screen in front of the solenoid. My dipstick show plenty of oil, up at the max line, but I don't have anything to monitor oil pressure yet.

Race Miata

Maybe try disconnect the VTEC solenoid connector and see if you get a CEL?

Slows2k

Electronically it is impossible to have the Solenoid and switch operating correctly and not have a CEL. Both circuits are monitored at all times by the PCM. If you unplug the pressure switch you will have a CEL immediately with a P1259 VTEC system failure stored.

When the PCM commands the solenoid to "On" the VTEC pressure switch must be "Off" or the same P1259 stores.

Race Miata

Yeah, that's what I thought and that's why I suggested that simple test to see if "his" PCM can in fact detect a VTEC circuit failure. IMO, it doesn't hurt to do some simple elimination test for troubleshooting purposes.

darkfx

Tell that to my engine then. I had no CEL and VTEC did NOT work b/c the oil pressure wasnt in the range. I have a spun main bearing.

Slows2k

Electrically it did work. It didn't have enough oil pressure to keep all the rocker pins locked out.

You also had a low oil pressure warning light flashing at you.


VTEC needs 60+psi of pressure and lots of volume to keep the rocker pins locked out. If one of the rocker pins was missing it would cause a large internal pressure leak and not keep the rockers following the high lift lobe. If the oil pressure falls below the operation threshold 60psi , the oil pressure switch command goes back to "on", and sets the P1259