Okay, to start things off, I don't have a code for you guys, because the CEL came on and then went back off. That said, here is what happened.

I was driving back to shreveport from nashville, and had been on the road for about 2 to 2.5 hours, about to stop for gas and food. It had been raining cats and dogs for most of the drive. I was coming up on traffic, and needed to down shift and get around, so when I do the car picked up normally until vtec. Where vtec should have kicked in, it just bogged down and the CEL flashed about 6 times. I slowed down to about 3000 rpms and the CEL was gone and the car drove fine. I decided to try again just to see if it wasn't some random fluke. Sure enough, the same effect. I pulled into a gas station, filled up, checked all the fluids and let the car sit for 20 minutes. When I started it there were no problems, no malfunction indicators, so I resumed the trip. From there on out, everything worked fine. vtec functions as normal, all is good. Obviously I couldn't get the code because it was only a temporary thing. The manual says it involves emissions, but I don't know. I'm gonna take it to Honda on monday morning and let them check it out, just wondering if anybody has seen this before.

Austin

 

I believe, and I'm sure someone will correct me if I'm wrong, that there are at least two factory prescribed conditions under which the ecu will prevent VTEC from engaging:

1)coolant not up to temperature
2)too little fuel

(number 3 would be oil level too low, but that's a mechnical condition, not an ECU enforced one).

That being said, I don't recall hearing that attempting to hit VTEC when one of those conditions is present triggered a CEL, but my guess is the low fuel was your issue. I'm not sure what the fuel level threshold is for the ECU refusing to go to VTEC is, but you can probably dig it up if you search a bit.

 

Since it was an intermittent thing and since you don't have the code, on what basis would you claim that the manual "says it involves emissions"?????

 

Cel flashing often means mis-fire. Again, I'd expect a continuous code if it was misfiring. It flashes because there IS a threat to the emissions system. Misfire can destroy the cat by dumping raw fuel into the exhaust.

It might not be a vtec issue other than trying to go into vtec causing mis-fire.

 

Question for UPR : Do you have any intake mods?

Question was triggered by the raining cats and dogs comment.

 

Yea, AEM CAI, which I thought could be the culprit. It has the bypass but that wouldn't help in the highway. You think it was just sucking in too much moisture that was causing the problem?

 

Water vapour doesn't burn
Maybe it caused a temporary misfire?

Allthough some WWII fighter planes had water injection to help the boost.
Not really for boost but to cool down the rich compressed air/fuel mixture so it doesn't detonate and/or pre-ignite.

 

Update: Took the car in this morning, and as I expected, no codes and everything "looks fine to us"

They will be replacing my map sensor because of a service bulletin.

 

Do tell? What did the service builtin say?

 

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