So i dropped an lsvtec engine in my integra 1997 ls. I had a p73 ecu (jdm itr) to use with this set up i will eventually get a p28 and tune but for now this is all i have to run it, i am 99% sure the ecu works fine.

Anyways i got the engine in and it is a b18b block with a gsr head and itr cams, skunk2 intake manifold and throttle body.

The car idled fine for the first few days, then it started lobing and whistling loud.. to check for vacuum leaks i covered the throttle body .. the car dies and holds the vacuum left inside the intake manifold just fine after its already off the vacuum stays inside the intake manifold. when you release your hand on the throttle body it pulls the air into it . So it is not leaking anywhere from what i can tell..

it lobes from 1100 to 2500 but only after you smash on it past about ~6 grand. After you go past 6 grand it will not idle normal until you reset the ignition.. the wire harness i re used is from my stock integra ls engine harness, so it know it works fine, because my car ran fine before i put the ls vtec in it. I already swapped out the idle air control valve with the one that came on my ls (b18b) when i put the engine in. I re used mine because i knew it worked and the one that came on the skunk2 intake manifold looked a little dirty...

So it holds a vacuum
it only lobes after you go past 6 grand and makes a whistle noise until you reset the ecu (the whistle noise sounds like its coming from the idle air control valve because, when you plug the little hole for the iacv in front of the butterfly in the throttle body the car will die)
once you reset the ecu with the ignition the car will stop lobing, idle normal (sometimes a bit high 1200-1500) but will not lobe until you get past 6k again.

This problem happens with both the ls p75 ecu and the jdm p73 ecu there for i do not think it is an ecu problem, i tried swapping the iacv with the one that came on the motor, and both will lobe.

I am at a complete loss i do not know what is going on.....

please help any advice is APPRECIATED VERY MUCH!

 

Well for anyone who reads this and wonders what i ultimately did to fix it...

I ended up swapping IACV's which did not fix it .. it did the same thing.. oddly enough

So i was not content with that and cleaned out one of them with an ENTIRE bottle of Fuel Injection Intake Cleaner... also sprayed alot in the map sensor port w/o the map sensor in there of course... and put it all back together...

problem solved. car idles normally now.