I tried searching, but couldn't find any definitive explanations and answers.....

Haven't had my 01CLS for but a month now. When I bought the car, I am POSITIVE VTEC kicked in at 4800rpm, it was clearly audible. In this time frame, I have changed the fog/parking lights (should be irrelevant), put in a drop k&n filter on stock box, and changed the spark plugs to Denso Iridium. Now, if you have read some of my recent posts, I installed 4 spark plugs and kept 2 factory for about a week. This was because I thought I had stripped the last 2 bolts that hold the coil packs in place. Turns out that they were not as bad once I had some time to look at them again, and I got them out with some elbow grease. I also noticed that the vacuum tube for the bypass actuator valve was unplugged, so I plugged it back in. Doing so did not make a difference, as ever since I have installed the initial 4 spark plugs (after k&n), VTEC now engages (more like jerks) at 5200rpm. I do not see a reason for this. I thought before that the 2 cylinders might be misfiring due to lesser quality spark plugs, but this does not seem to be the case after they were changed. The k&n provides more airflow, so it should not mask sound or inhibit power around VTEC. Instead of the "switch" effect of regular VTEC, it now almost jerks into VTEC at 5200rpm. This is not just based on audible factors either, because you can feel the pull start at 5200rpm, not 4800rpm. The bypass actuator valve flips correctly, and you can hear the sound change at 4000 with it. So, I am wondering what is going on. Another thing I can think of is the tranny was replaced (not rebuilt or repaired) at 60k, although everything was fine at purchase time with VTEC. Could the increased airflow have confused the ECU or something similar?

 

EDIT: I will try and post a video from my camera phone soon to let anyone who reads this be the judge. Maybe it is psychological, but the way it stumbles into VTEC is like a person sprinting 100% to the point they are almost falling forward. (If that analogy makes sense)

 

vtec change over is done via oil pressure ...low oil level will cause the car to first fuel cut a time or two maybe more before it finally may change as enough oil pressure is made

 

does it do it all the time remember that vtec is based on a lot of things specifically engine rpm, vehicle speed, engine coolant temp and engine load. load and temp really effect it, if its too cold it will not switch over and if the load is different it will change the rpm. oil pressure is not part of the equation because at that rpm oil pressure will be high enough that it will not matter. now you could be having mechanical troubles maybe a stick vtec solenoid, hook up a volt meter with really long lead to the solenoid and tap it to the windshield, when vtec switches over you should see 12 volts, if you see 12 volts at 4800 but no switch over you know you have a bad solenoid its really simple.

 

Low oil levels or pressure DOES disable or inhibit VTEC, actually. So yes, oil does have something to do with it.

Also, VTEC in the J32A2 doesn't vary the RPM of the change. It's 4800rpm for the J32A2 (4400rpm for the CL-P's J32A1) at all times unless there is a problem.

 

Yes, there must be something going on then. The temperatures have been in the 20's and 30's lately, but when I changed all 6 plugs to match, it was like 60 degrees and still 5200 rpm switchover. I could check the solenoid (civicking), but where is it at? Also, I have never checked oil pressure before, any help? I am trying not to take it to the local JACKURA stealership. Thanks for the feedback.

 

the vtec solenoid on these cars is part of the oil filter housing, if you have a acura repair manual it will show you how to test it. for oil pressure you need a kit and most of them work by replacing the oil filter with a paper and a gauge goes onto it. they say at 4000rpm you need 52psi if i remember my specs right.

 

have you checked your oil level?

 

I will check oil level tomorrow, but it was changed about 1500 miles ago so I'm assuming it is fine. I have noticed that recently the VTEC engagement has been much more normal with the nice weather again. So, maybe it was effected somewhat by the cold, and just adjusting to the sparks and increased breathing.

 

if it's oil level it'll happen alomost exclusivly on the 1-2 while WOT or on an aggressive turn,situations that will cause the remaing oil to move away from the pick up

 

Sorry for the late post, but oil was slightly low and I am taking for an oil change on thursday (guess I have put on more miles than I thought). This may have had an effect, also since I have taken my car to the dyno, my ecu may be contributing. On dyno runs with the engine left running after the previous run (even with cooldown), wtq and whp were both down 20, exactly and consistantly. Then flip the engine off then back on, even without cooloff, and numbers are back to normal consistantly. This was covered in another thread, but I am having the dealer check the ecu as well. Might there be issues with my tach even? I wonder because according to dyno, peak power came 400rpm late, and peak torque did the same. VTEC also seemed - you guessed it, 400rpm off. The dyno software pegged VTEC right between 4800-5000rpm though...