I have a 00 si that I just put an ls vtec motor in that I bought from somone off this board.. I was running an obd1 p72 when I first put it in about 2 weeks ago ran fine.. I ran into some problems with my jumper harness so I put the stock si ecu back in it. Everything was great for about a week then slowly my vtec was cutting out.. It would kick in at 5500 rpm or wherever it kicks in at but it would cut out nearly instanlty and kick back in at about 7k. It was doing that for about 3 or 4 days and then today it quit working complete and my car govenors(sp) at at 7k rpm.. Any suggestions before I start messing with it tomorrow? The car has plenty of oil and my speedometer works fine.

 

If you added VTEC yourself i would check those wires, sounds like somethings not on right. Also any codes?

 

well my cars equipped with vtec since its an si.. The only thing changed was the ls block.. It has the stock wiring harness and an si head.. There is codes but it had them from the beginning becuase there isnt a knock sensor.. Im not sure it has any more codes. I'll check that in the morning.. I was just looking to get any info on it from someone who maybe had the same problem in the past

 

I think Knock sensor throws you in limp mode. So VTEC wouldnt work. Also check your oil if theres no oil then no VTEC.

 

Yeah theres oil.. But I think if the knock sensor threw me in limp mode it would be something that was instant and continuous not periodic then continuous

 

go get your valves adjusted