RocCitySlayer
10+ Year Contributor
- 792
- 7
- Nov 20, 2011
-
Rochester,
New_York
If i tighten down {in} the biss screw, How many complete turns {out} should i turn it to have it positioned right?
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With the car warmed up fully, you want to unscrew it until your ISCPosition value in link shows 30.
X2 - mine would take 5-10minutes to show adjustments.Just make sure to make the adjustments slowly, monitor your progress, and after each adjustment let it settle in for a bit before making another.
Without a scan tool its a matter of trial and error. Though 2 turns from closed should do it but that can change depending on boost leaks etc.
Give turning it a shot little by little and let the car adjust and check the idle, if its not where you want it to be keep tinkering with it.
You do that with a timing light, i've never heard of anyone doing that with a biss screw.Don't you have to ground a test plug to do this? I thought i remember doing that based on the write up in tech forum.
Thanks, sorry for the misinformation! I've never ground my biss before and i've always had a perfect idle though. Donniekak has helped me a lot with DSMs and even him, i've never seen do that. Makes sense though how it works.Now you've heard of it (after reading the link below, of course).
1G BISS Adjustment
I just make sure that I have zero Boost Leak and everything in good working order, and I just play with it until it gets to 750 rpm.
Other wise, I would go with the 2 full turns before close position.
This is not the proper method on a 2g & what your doing is basically taking a guess where the correct spot is. The BISS screw is not use to adjust the idle, its used to center the ISC in the middle of its travel range to allow it to have most control over your idle. A side effect of adjusting the BISS is it may change your idle rpm but this is not a proper way to set it or your idle.
Just turning it a certain amount of turns may get you in the ballpark if your TB is 100% stock & there are no leaks & you haven't made any changes to it (though not a precise way to set it). But if you've made any changes to your TB or have leaks, etc, this method is basically a guess.
If you want to set the BISS correctly on a 2g you need the scan tool or ecmLink.
Any chance u know a link to a thread for making a boost leak tester?
I thought you said in your tuning thread that you had already checked for leaks
I tested for boost leaks and my turbo to manifold was leaking but its fixed now after my turbo project i was working on.
Any chance u know a link to a thread for making a boost leak tester?
This is not the proper method on a 2g & what your doing is basically taking a guess where the correct spot is. The BISS screw is not use to adjust the idle, its used to center the ISC in the middle of its travel range to allow it to have most control over your idle. A side effect of adjusting the BISS is it may change your idle rpm but this is not a proper way to set it or your idle.
Just turning it a certain amount of turns may get you in the ballpark if your TB is 100% stock & there are no leaks & you haven't made any changes to it (though not a precise way to set it). But if you've made any changes to your TB or have leaks, etc, this method is basically a guess.
If you want to set the BISS correctly on a 2g you need the scan tool or ecmLink.