Replaced ISC now idles fast

[LKWTSI]

Car would occasional die coming to a stop after being on the throttle for a while. Took the ISC out and did all the required tests and found the Ohms were good, but the 6volt power test failed. So replaced with ISC (which tested good all over) from a 92 eclipse and spliced the wires for the different connector as the 90 doesn't plug directly into the ISC. While off I cleaned the TB and resealed the emmision vac' ports that have blocked off.
After initial start up car ran rough, attributed to the crap burning off from the cleaning fluids. Idle settled down about 1500rpm. Took for a drive and idle stayed at 1500 rpm. Let engine cool and took for a drive next day, same thing.
Two things come to mind. I took the TPS off to clean TB and didn;t realize it can be adjusted. Also, BISS is screwed all the way in. Previous owner was a dips#*t and I'm conbstantly fixing his mess.
SO, any takers as to what might be causing the fast idle. I haven't figured out what tests need to be done for the TPS, but don't know if any are needed. As for the BISS, seems strange it's now off, when all I did was change the ISC motor.

 

[hdoerr]

The BISS may have been turned in to work out the initial idle problem. Try backing it out to see what happens. Also check the TPS via logger to see if it is partially open.

 

[LKWTSI]

Will try backing the BISS out and see what happens. As for the TPS. I'm still new to the upper end tuning of DSM's, so how do I check it with a logger? I don't have one if you get my drift. Thanks for the response.

 

[Artago]

Will try backing the BISS out and see what happens. As for the TPS. I'm still new to the upper end tuning of DSM's, so how do I check it with a logger? I don't have one if you get my drift. Thanks for the response.

If it's idling high then backing out the BISS will make it idle even higher. (Try it and you'll see)

Setting the TPS requires a logger such as pocket logger. Might be time to invest in one.

If you're idling high it means you're motor is getting too much air at idle (Logger will tell you this too). You might wanna check for vac leaks in the throttle body. You'll need to build a boost leak tester.

Good luck.

Tom

 

[boostngsx]

I just replaced my ISC and I got the same thing. Im hoping its just a leak around the throttle body.

 

[Lofty]

Back out the BISS without gator clipping anything. The ISC will fight the adjustment so it will be backed out but the biss will still make it idle the same. Then follow the BISS adjustment at vfaq.com and then screw it in more, it may fix it.

 

[daren_p]

Did you disconnect the battery to reset the ecu? If not, give that a try. The ecu doesn't see any feedback from the ISC for its position so it relies on knowing its last position & goes from where it thinks it still is. If you reset the ecu this will reset the ISC to its center postion & then it can adjust properly from there. The proper operation of the BISS isn't to adjust (though this will happen when the ISC is at its limits) the idle, its to keep the ISC in its centered position.

 

[boostngsx]

Not to steal the thread or anything but since I did my ISC I notice a popping sound in my idle. It sounds fine and the pop pop and fine again. Now when I down shift it pops like crazy and I dont really slow down much. Any idea on what that may be?

 

[Lofty]

Not to steal the thread or anything but since I did my ISC I notice a popping sound in my idle. It sounds fine and the pop pop and fine again. Now when I down shift it pops like crazy and I dont really slow down much. Any idea on what that may be?

If you're talking about exhaust, mine popps hardcore on downshifts.

 

[solidviper89]

my 3" exhaust with a borla muffler sounds mean when it pops... kinda annoys me now but was cool at first, new sound my baby learned to make.

 

[boostngsx]

Well I guess its nice im not the only one. I have a 3" turbo back, its really loud on a downshift.

 

[LKWTSI]

Thanks for all the info guys. I didn't do the swap with the Bat' disconnected, but will do it and see if the reset helps. As for the logger and BISS adjustments, I'll get after that per the VFAQ info. Any hints from you guys running a data logger what would be a good start as far as equipment necessary and any software that's required?