so i pulled my throttle body to rebuild it and have the housing powdercoated, while its out can i block off the ISC and FIAV, i dont have link yet but i will after the christmas just want to make sure i can still drive the car, its a 93 with a 6 bolt swap if that means anything. i tried searching but couldnt find a good answer to my question. main reason for eliminating is the car does a weird idle surge and stalls occasionally at idle so im trying to eliminate alot of the possible issues.

eliminating it will just make it worst than good. Get a new isc. Block of your fiav but leave the isc open. Your problem could also be a boost leak.

On a DD vehicle, you should want to retain the ISC for ECU controlled idle. You will have a difficult time idling properly as you are solely relying on the BISS for your throttle plate bypass when removing both.

You can remove the FIAV just fine however and can be done for free via this method.
http://www.dsmtuners.com/forums/articles-intake-exhaust/391977-free-fiav-block.html

well the point on the ISC is very worn and im sure its not sealing. thats why i asked if it could be eliminated. from what i just read eliminting it will cause it to want to stall upon sudden throttle closing, can this simply be adjusted by the BISS screw? i know there are guys out there not running these things.

plus ive spent so much on the car this week i really cant afford another 100 for a new autozone "Durafail" sensor..

The ISC isn't supposed to seal to anything. These cars came from the factory properly working, so there is no reason that it won't work properly again. Granted DSM's do not have the best idle control, I can promise it will suck not having an ISC. Guys runnign without them, are either A.) retarded and don't care that there car is a pile of shit, or B.) Running monster cams, and idleing at 1000 and have no accessories.

Without an ISC, your car will stall when you turn on the lights, or turn the steering wheel, or the A/C. The ISC quickly bumps up the idle when there is a load on the engine. You'll loose all of that, plus you'll have to baby sit you car when its cold.

Now to fiw the actual issue, what have you done?

Have you tested the ISC coils? The Idle Position Switch? Do you have the ground strap on? Have you checked for vaccum leaks? Is your TPS set correctly? Is the timing set correctly? How about Cam timing? Is your motor in good shape? Do you have a MAF that's hacked to ####? All of these are possible causes for bad idle.

I would advise blocking off the FAIV, as its probably shot from age and not very consistent. My idle improved dramatically from blocking it off.

But start first by checking for vaccum leaks, a hacked maf, burned coils in the isc, and the ground strap on the tbody.

Then properly adjust the BISS

You will have to adjust idle warm using the BISS and throttle stop, I have removed both on my car. When the car is cold you will have to hold your foot on the throttle till the temperature gauge reaches normal operating temp. Once that happens it will idle rock solid.

It is a bit annoying but you will get used to it.

1997_GSX said:

You will have to adjust idle warm using the BISS and throttle stop, I have removed both on my car. When the car is cold you will have to hold your foot on the throttle till the temperature gauge reaches normal operating temp. Once that happens it will idle rock solid.

It is a bit annoying but you will get used to it.

Click to expand...

I've removed both and have the exact same results. after its at operating temp it will idle EXACTLY where you want it to( you could also do that with link, but thats a different topic).

Also something to keep in mind, what bastarddsm said about the voltage is correct. I had my idle set to 1000 and whenever i would turn on the lights the rpm would drop to about 900.

If you can live with the cold start issues(holding your foot on the gas til it reaches operating temps), remove both. It worked for me.

There is a slight work around with the idle issues once load is applied and your RPM changes. So far, I've only done this with ECMLink but it's all in setting your injector dead time.

This is a more tedious method but you do get better results.

We all know (assuming you have used link) how setting dead time works for your fuel trims, yes? Well that's the first step. That is setting a global dead time over all voltage ranges.

Your next step is to work the injectors battery table under direct access. Yes this little unknown table works magic. All you are going to do is essentially do a log, apply load and watch how your fuel trims change at a specific voltage.

Generally I've only had to go down to 11-12v for most load issues but on the DA table you add or remove dead time at the voltage that shows the idle issues from the load. Generally you will be increasing dead time to supply more fuel.

This gives you a much better idle adjust and will solve most electrical loaf based rpm issues.

I was having some serious bogging issues everytime my coolant fans would come on, this solved it wonderfully.

It may work with engine load as well provided it pulls a drain on the battery as it occurs. It's at least worth the effort to log and reviews what is going on.