VTEC has worked flawlessly on the car ever since I built and swapped it. I haven't gone completely through the VTEC troubleshooting guide yet, but I was hoping that someone might have had the same issue and could point me in a direction quickly. A bit lazy, I know, but I don't have access to compressed air so I can't do some of the troubleshooting.


Here's what it does:

After initial warmup and driving, VTEC will not engage. If I keep trying it, eventually it will engage and perform flawlessly every time until the car is shut off and cooled down. This makes me think it's mechanical, not electrical.


Here's what I've done:

• Replaced oil, I usually use 10w-30 but I used 5w-30 this time. Oil pressure was, and still is 15-20 psi (hot at idle) running to the 80psi cutoff around 4k RPM. Oil pressure doesn't seem to be the issue.
• Removed VTEC solenoid, checked and cleaned oil screen. It had a tiny bit of RTV that came off the gasket when I installed it in the screen, about the size of a BB. Otherwise, spotless. After cleaning, no change.
• Checked solenoid wire to body ground resistance: 15 ohms. Within the range of 14-30ohms. Checked again at engine operating temp, 18.5ohm, still good.
• Can easily depress solenoid piston by finger.
• Put 12v to solenoid wire and it clicks.
• Tested coolant temp sensor, got 9 kOhms with engine cool, checked at various times after starting, reading went down correspondingly, ending at 0.198 kOhms after fans came on twice.

The car does sit for long periods of time, usually a couple months in between VTEC'ing. I do start it and let it warm up fully every other week or so.

 

So after I posted this I figured I should stop being lazy and work through some troubleshooting. Added everything I tried to the original post, nothing helped.

Started thinking about the wiring to my ECU, checked it, and lo and behold, one of the wires (I think for the IACV or something like that) had come loose from its connector. Crimped it back in, some heatshrink, and voila! VTEC works every time now.

THANKS FOR NOTHIN' YA HOSERS

lol j/k