vtec cross's over when car is cold!

[jdm2gen03]

ok so i jus got done doin the swap and i'm throwing a few codes but will be cleared in a few days, anyhow we took it for a lil test drive start it up and pull it out and get into a lil bit and vtec cracks. which usually doesnt happen unles the engine has proper oil pressure, and the car usaully has to warm up to do so. so my question is will this effect anything, cause any damage, and also why is it doin this.

 

[n20hatch]

Well, my car used to have this problem, I changed my coolant temp sensor and it was fine. I wouldnt take a cold motor into vtec though, somebody back me up with reasons here.

 

[E_SolSi]

engine not warmed up to proper opperating temp + stupid high RPMs (5K+) = BOOM

high revving on a cold engine caused all sorts of added wear and potential damage
in short..... DONT DO IT

 

[xj0hnx]

When you say "a lil bit", are you talking ten second, ten minutes, two minutes? Motors heat up fairly quick, so if you started it, drove half a mile, and then hammered it, the ECU is probably seeing the tempature it wants, as long as it has that, the right RPMs, right mph, and the right negative pressure at the intake manifold, you're good.


But yea, it's better not to jump in turn the key and hammer it.