90 Idle surge after TB swap

[abakja1]

I just had recently had an engine rebuild completed and had put in FMIC, Evo16G, and a bunch of other stuff too,...Car was running strong with the exception of running rich due to larger fuel pump, but I just got an S-AFC 2 and gonna tune when I got new knock sensor,..But I developed a boost leak cause when I got to 1-2psi my car would bog and stumble,..

I have a May 1990 GSX and put in a later 90-92 TB (to fix boost leak due to tb seals) and so I could block off the FIAV and coolant hoses to TB,..I got a used tb and RTVd FIAV and put in new seals for throttle plate,...Different TPS was put in and rewired along with ISC (different harness connection compared to my old 90 tb),...

As soon as TB was installed, I started it up and my car went straight to 2k rpms,. throttle cable was check for tension and it was slacked off enough,..I checked everything (BISS screw, connections etc) and thought ISC could be bad,..Next day I proceeded to change to another ISC (that I knew was working) to see if that would work,..

When I put in the 2nd ISC, car started but stumbled so I adjusted the BISS screw and it idled ok at 925rpms,..It did not go straight to 2.1k rpms like it did on the first ISC,...But when car warmed up, it went straight to 2k rpms again and surged between 2.1-2.3k rpms,..I checked the TPS settings, Biss screw, Throttle cable too,..Cold startups differs now so that I dont kill my battery as it sits in my garage,...sometimes at cold start it goes straight to 2k rpms and surges or sometimes it stumbles and needs BISS adjustment to idle ok,.but goes to 2k rpms as engine gets to operating temps,..

I checked the links about idle surge, checked off one by one what I checked on my car. It comes to electrical but I dont know how to make a LED to check voltage out of wiring harness for voltage but will check ISC with DVM later for resistance,..If anything, I will try to put on a plain FIAV lower portion of the TB that hasnt been RTVd and put it back on along with the coolant lines again to tb,..Maybe bypassing all of this (even though Im in Hawaii) isnt worth all this trouble and maybe a solution,..Its my last resort as TPS and ISC should be good,..maybe its the FIAV cause I swapped 2 upper portions of the TB (to make sure it isnt a TB plate or seal leak) but still get idle surge,..Ive been using the same lower FIAV with RTVd sections,..so maybe this is the cause?

Anyways, it like I got a new rebuilt engine with a lot of mods and have driven my car for like 3 weeks total (still restrained as it isnt tuned or broken in yet) since last September,...Anyone got any more advice??

Thanks
Kevin

 

[L2RTSiAWD]

Moved to Problem Diagnosis.

 

[abakja1]

So how many of you guys are running your car with a bad ISC and screwed up idle like me as described above? I wanna drive my car but am afraid of what damage or danger there maybe with a car that with an erratic idle at 2k rpms,..

People locally in our DSM club have idle troubles and drive, but I rather fix this problem and get it over with,..But so far, I havent found any answers to my problem,..They said that their idle falls back to normal after their car has reached operating temps,..But since this is new to me and since my car hasnt left my garage ever since I started it up with the tb swap, I dont know what will happen if I take it out for a drive,..This is new territory for me and maybe some of you who are more familiar with this problem can fill me in on what to expect if I cant remedy this problem,..

Kevin