Allright, this isnt my first swap more like the 10th so Im not completely clueless except when it comes to this.

b18b ls swap in my 97 ek. Running rywire obd2a-obd1 harness and P75 ecu. Motor is bone stock. Running open header at the moment (i know i know), open test pipe actually. When I cold start the car the idle is very high about 2500 rpms, and comes down to 2k pretty quickly. car will idle fine like that forever but as soon as you give it any gas, it starts surging 2k-1k 2k-1k that too will eventually stop after a few minutes, and restart again as soon as you give it gas. NO CEL's!!! ECU was reset, COOLAND BLED, IACV was changed and cleaned, running the ls throttle body so it has a FITV, I have an R throttle body I would like to try. You guys have any clues? Unplugged the IACV does nothing for the idle except throw the code.

 

 

hows the tps sensor? Might be the case had that happen to a friends car.

 

everything was working fine from the car this swap was pulled from. does the TPS sometimes not throw a CEL? as far as vacuum leaks I dont know of any. If I place my finger over the hole inside the throttle body should the engine die or idle down and still run?

 

if you have your finger over the hole it should idle perfectly...shouldn't die...if that happens...then you will have to get it fixed...forgot what happened, but my cousin said that if you beat on an ls motor to redline or try passing redline it will cause a sensor to go bad in the throttle body and cause that annoying idle...bet ya did that eh? ahahahah...my cousins ls teg was like that after he redlined his motor real bad...but yea...it is all in the throttle body...switch it with the R and see what happens...and i think it is the tps...hmmm...i'll have to talk to my cousin on that...can't remember though...but good luck man

 

no I have not been giving this motor much hell at all, it maybe has 25 miles total on it since break in.

 

 

 

Injectors and old gas were the problems with my b20 swap

You could also check timing, spark plug wire order, injector wire order, ...

 

think having an obd2 vtec dizzy with only 1 bolt lining up would cause this issue?