Folks,
We all know about how the engine has to be properly warmed before the car will allow you to enter VTEC but what about the opposite side of that coin?
Here in North Texas, the air temp has begun to reach 100 F and the road surface is even hotter. I have noticed that my engine will continue to accelerate past 6500 rpms but VTEC won't kick in.
Is this a hot air breathing problem or do I have to start to worry?
Thanks.

 

I haven't noticed a problem with VTEC not engaging, but I have seen severe evidence of power loss due to high intake air temps (IATs). Or, at least that's what I'm blaming it on. Here's a dyno to show just how much of an impact heat can have:



Just before I had this dyno done, I noticed that the car felt like it was pulling a parachute behind it. In 2nd gear it felt like it took 10 seconds to get from 40 to 60mph.

I haven't ruled out the possibility that this was a MAP sensor issue, though. I felt a similar power loss one evening when the air temps were much cooler. I took the car home, did the MAP sensor whack, and the car felt stronger afterwards. Could just be the placebo effect, though.

 

This may sound a bit simplistic, but could it be that VTEC isn't engaging because there's not enough engine oil? Is there a CEL? Perhaps the VTEC solenoid is faulty?

Those ambient temps are what we see year round here and VTEC kicks in all the time except for when the temp is at 1 bar.

 

Thanks for the replys.
Just 1500 mi since the last oil change, shouldn't be low but you never know. My wife has had the car all week...at the airport no less since I needed the four seater to haul the kids while she was out of town. I'll check it tonight and see.