Intermittent 6k Rev limit??

Hi guys, I completed a 6speed conversion last week and ever since, I have an intermittent 6k Rev limit, particularly in 2nd and 3rd gear, sometimes it will happily Rev to 7,200 being a VVTI but sometimes it will hit the limiter at 6k?

I have read that it could be spark plugs and fuel cut however I have them waiting to be fitted but other people having the same problem in that past has already had these fitted to their car.

A few people mentioned doing the conversion still using the auto ecu, bypassing the park/neutral switch then it thinks it's in park/neutral all the time but then why does it only have this problem in certain gears and why is it intermittent and not constant?

Any ideas?

Have you tried using a manual ecu? I did the conversion using the auto loom a bypassing the neutral start position switch and it was fine with a manual ecu, not entirely sure but this maybe could be a cause

Manual ecu would work. I had this problem when I fitted an auto tt lump to my N/A years ago. There's wire on the engine loom that you can cut to cure it.

I haven't tried a manual ecu mate, the 6spd VVTI ecu's are ninja to find.

I'll try find out which wire to cut hopefully that sorts it but surely if that was the case why doesn't it always impose the 6k Rev limit if it thinks it's still in park, because sometimes it's fine.

I've found that if I don't put my foot down for a while then suddenly I decide to floor it in second it will Rev to 7200, then change to third and it will only Rev to 6000

Thanks for the comments guys

This also sounds like a alternator fault one the wires was bad on mine which caused this