Today I was out at a NASA event in pretty normal conditions - sunny, 80-85deg. For the first 4-5 laps of a session, the engine power felt normal. On two occasions, after the 5-6th lap, the engine will suddenly start losing power and it felt like VTEC wasnt engaging. To put it into perspective, my friend was trailing me in a new Miata. For five laps we were running pretty close, then when my car felt like it was losing power, he blew by me like I was sitting still.

After the session I parked the car and let it cool. 20-30 minutes later I started it up, but the engine died. I restarted it and it wouldn't idle, I had to hold the RPMS at 2000 or so for a minute or two. After I held the RPMs up for a couple minutes, it "cleared up" and idled and ran normally. Earlier in the day I ran a track session, parked, then started it an hour later and it was idling around 400-500rpms with the A/C on. After a couple minutes if just cleared up and ran fine.

Is there a chance that the oil is heating up and thinning, causing a loss of oil pressure so VTEC doesn't activate? Or could the ECU be pulling timing due to intake air temp? Any ideas? Has anyone had an issue like this?

 

No CEL?

Is the MAP sensor plugged in?

 

sounds like it just overheated. oil pressure def could be an issue, i see in your mods the previous driver had a "spicket" you said. Did you ever change that? and did you check oil later?

 

No CEL and the map sensor is hooked up. Last night I was messing around with the vacuum lines to install some Krank Vents (i didn't actually install them though) and when I got to the track this morning, one of the lines was disconnected by accident. I hooked it back up and there was no CEL, but I'm gonna run a scan tool anyways to see if something's up.

 

Yeah, it has a normal drain plug now. I checked the oil before every session and it stayed on the full mark all day.

 

What was the air temperature? I had some issues like that last season after a 45 min race in really hot weather. I haven't had an issue since and didn't have that issue the next day. I have found on the dyno that the car is much happier under 200 deg F on water temp.

 

I'm concern about the fact the engine died, and wouldn't start/ran bad.

That sounds like a bearing. What did it sound like when it was having trouble idling?

 

It sounded totally "normal", it just wouldn't idle. Earlier in the day I noticed the problem when I was idling on grid with the A/C on. If I blipped the throttle, it would rev up, then dip down to 400-500rpm, then recover back to normal idle RPM. After a few minutes it was fine.

I noticed this issue at my first event a couple months ago, but it wasn't as pronounced. It was also a lot cooler on that weekend. Yesterday it was hitting 85deg ambient.

Don't say rod bearings! lol

 

Try cleaning that air/idle valve on the throttle body.
Mine idles ~500 if I 'putt" around town a bunch. Then I beat on it and it runs great.. I notice it when I leave my house w/out any "warmup" time and it's idling cold at the first stop light or two..
Mine has never stalled or had any issues starting.

 

Thinking about it you might have got a bunch of oil up in the intake also..
All those massive geeeezzz on the east track w. hooshah's!