its on top of the TB. Though, I would advice not to mess with it. The ECU does enough calibrations to let the car idle properly. Adjusting the BISS screw will only mess up the fuel trims and will only hide the true problem.
does anyone know where the idle screw is located?i am trying to help tgc member P'NOYcaL.does anyone have a picture of the location of the idle screw?thanks.
its on top of the TB. Though, I would advice not to mess with it. The ECU does enough calibrations to let the car idle properly. Adjusting the BISS screw will only mess up the fuel trims and will only hide the true problem.
yeah because the screw is probably too far out creating a fixed orifice. close the BISS screw all the way and clear the code and let the car learn how to idle.
Opening the biss screw is like pouring water down someones throat who is already under water. You are diluting the mixture with unmetered air now.
sorry for the thread jack but whats the proper idle RPM? I seem to be idling extremely low (nearly around 500) and I feel like my car is going to die at idle
alternator is about 6 months old
If i screw the BISS screw all the way down disconnect the battery will the car idle fine? i had a problem a few months back and car had to get fixed at my school by votech. The kid said they played with that screw to try and figure out the problem. I idle at 1000rpm. But am also hearing that hiss sound too.
This is not correct!
The BISS screw has an o-ring that seals the the TB from unmetered air entering in the IM. The BISS operates by letting air in the IM though internal TB passages which sets the Base Idle. A base Idle means the revolutions of the engine w/o the help of the idle control valve (ISC). The base idle is usually set by using a logging tool whick monitors the low fuel trims.
What you're telling him, to screw in the BISS screw all the way and let the ECU relearn is not how it is done and it only masks the problem instead of fixing it. The symptoms will reoccur since there's an actual problem.
Simplest way to do it w/o logging tool.
Disconnect battery terminal and the ISC plug
Get a new BISS screw o-ring seal and a cap and replace them. Screw in the BISS all the way and reverse it a full turn. Connect battery terminal and start the car with the ISC unplugged (it may throw a code for that). If the car doesnt start the unscrew another turn, if it starts and it idles too high then screw it in some more. The point is to get the car idling steady at around 900 rpms. Shut the car off, plug the ISC connector. Start the car, if it idles the same good, if it doesnt then adjust to 900 rpms again. Unplug the battery, wait 5 min, connect it again, the idle should be still 900. Go for a drive with lots of traffic lights for at least 20 min. Make a stop, put it in Neutral and check idle, adjust if needed.
These are the part numbers for DSM. The 8g guys who have played with it should chime in and say if these are the correct part numbers
Biss Screw Cap MD614150
Biss Screw MD614948
Biss Screw O-ring MD608806
Last edited by mko; 01-27-2011 at 11:17 PM
very nice detailed info there mko! can someone just verify those parts before i start ordering them please. thanks
when you say ISC (idle control valve), are you talking about the IAC(Idle Air Control) valve? just wanna make sure were in this same area.
here's a picture of what im talking about pulled it out of jigz thread:
yeah its the same. iac=isc
it looks like, i cant really zoom in to see better
you can go to your local hardware or parts store with the BISS screw and get a o-ring, the closest size they have, of course, while you're waiting for the parts to come. There should be no hissing anywhere on the TB.
Also the threads in the BISS hole should be cleaned up prior to installing the new o-ring. There will be a lot of gunk from the EGR valve deposited on the BISS, and that gunk can damage the new seal while you're installing it. Try using the BISS screw itself (w/o the o-ring) as a tap and run it a couple of times thru the threads, use some parts cleaner and compressed air to dry the cleaner before it gets to the ISC
Last edited by mko; 01-28-2011 at 01:21 PM
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