Ok here is my setup
91 civic si
Built ls-vtec
SRP 9:1 pistons
eagle rods
Skunk2 tuner2 cams springs retainers ect
Motor runs great no smoke and less than 800 miles since build.

Now here is my problem, my buddy that tunes my cars went out with me and started to tune the car on chrome gold, its on 7lbs with a HX35w on a blox cast mani turbo comes online quik and hard but at bout 6900 rpms the car falls on its face hard the timing is dead on and the fuel is sufficient wideband reading mid to high 11's and it doesnt change but it wont rev past 7500 it basically just stops dead and the car feels very very healthy from 4-7k but after that nothing and the program says vtec is engaging and it isnt throwing any codes.

I only have 1 thing that i can figure, is there any way that the vtec solenoid or pressure switch is going bad and kicking out at high rpm but not throwing a code?

Help is much appriciated thanx

 

What are your plugs gaped at? Is it breaking up at hi rpm's?

 

catalytic converter clogged possibly...ive have this same issue befor just gut your stock one and bolt it back up...(get replacement bolts first they usually break from being so hot)

 

do the oil pressure switch bypass..i had a similar problem with vtec on and off when it felt like it...jump a4 to d6 and disconect oil pressure switch plug from solenoid then your vtec should engage all the time unless u left the o-ring on cam cap #3 off...

 

pull the vtec solenoid off and clean that screen that is built in to the gasket. i have seen it time and time again that is one of the few things that can cause vtec to not engage and not trigger the program to say there is a problem.

 

I agree with this statement, clean your solenoid and make sure there isn't any kind of dirt or grime in it when ur done. This is a common problem that makes the vtec to no engage properly and also can cause it to go in and out throughout the rpm range.

 

they are 8's and gapped to like 18 thousandths so its not blowing out spark

 

there is not cat lol it has a full 2.5inch exhaust with 2 resonators and a muffler

 

i will give this a try today thanx again i will keep this thread updated

 

update took the vtec solenoid off and the screen was pretty clogged up so im guessing that was what was wrong i havent had a chance to test it out cuz my inner tie rod went bad and the car is very scary to drive on the street now

 

ah man, that sucks. hopefully you can get the car running again soon. I am wishing my car was running right now .. i'll have to wait about another week though .

 

Just to be sure, recheck your cams & belt. Do not trust the cams to be indexed properly. SK2 has a good record for those things, but a majorly advanced cam will fall on it's face near redline. It's probably the vtec issue, but this happens too. Hell, I've seen a saab motor actually jump the belt forward 2 teeth. Sounds impossible but it happened.

 

K well i cleaned out the mesh screen and it was pretty clogged up and i thought for sure that was it but still falls on its face at 7500 ish. I am gonna re-check the wiring and get back to ya all on this