2g biss

[MyBeatGSX]

Has anyone done it or figured out a reliable, repeatable way to do it? I had horrible shaft seal leaks so I installed a 1G throttle body with new seals today. I started the car and it idled at 3,000rpm. Went back and checked under the hood... stupid me didn't plug the ISC back in. But to no avail, I restarted the car and idle slowly came down to 2,000rpm where it stayed. I didn't want to touch the BISS because I knew the problems it was going to create. I didn't really have another choice though, so I screwed it in at least 10-20 full rotations. This brought it down to 800rpm. After much fiddling and tweaking, it now idles at 750rpm... most of the time. Its still not dead consistant like it used to be, and as I pulled into my garage which involves almost launching the car and then quickly stopping so I don't roll back over the cliff opposite my garage door or blast through my downstairs livingroom wall. Of course the car immediately died, which annoys me. It ran fine all night and I reved the crap out of it before leaving the house and it never stalled out once.

Bottom line, I need a way to adjust it without the scan tool. Trial and error doesn't seem to cut it. It either idles too high or stalls out, I can't seem to find a happy medium. Even when its was "working" for most of the night, idle is still fairly irratic. With my old TB it went between 720-760. It now goes anywhere from 680-820. IMO, I've driven it enough that ECU should have relearned the idle, it is using the same ISC after all....

I also did another boost leak test, there are no boost leaks so a vacuum leak isn't causing the problems. I do have a lightweight flywheel, I know I've heard of stalling problems before. However it never happened to me on the old TB so I don't see why it should start happening now.

 

[daren_p]

Can anyone verify the LearnedIdleAdj I have seen both 140 & 144 posted in several places, which value is correct?

 

[zippyshoe]

Can anyone verify the LearnedIdleAdj I have seen both 140 & 144 posted in several places, which value is correct?

The LearnedIdleAdj begins with a value of 144 after cycling power (reseting) the ECU. From there, LearnedIdleAdj slowly changes until the ECU "re-learns" your vehicle's idle. Therefore, if you adjust the BISS to achieve a value of 144, then this will minimize the amount of the time the ECU needs to re-learn your vehicle's idle. Hence, the value of 144 is best value to shoot for, however the value of 140 is considered to be close enough. Hope this helps!

 

[jabinya]

Well I don't have DSM Link but I do have a logger. Can I monitor Learned Idle Adjust from my logger? I don't see a sensor value matching that title, is it called something else?

 

[zippyshoe]

Well I don't have DSM Link but I do have a logger. Can I monitor Learned Idle Adjust from my logger? I don't see a sensor value matching that title, is it called something else?

I own a Pocketlogger, which I bought before saving up for DSMLink. Unfortunately, Pocketlogger does not provide access to the LearnedIdleAdj value (or ISCPosition for that matter.) I am not aware of any loggers which provide access to this value. Which logger are you using?

 

[jabinya]

digimoto.

 

[jabinya]

I canceled all apointments tonight and spent my time in the garage ironing out my idle problem.

Just a refresh, on my 2G 60mm TB I have the coolant lines leading into the FIAV unconnected and have no MULT-II OBD scan tool, only a PC ran datalogger.

I started with readjusting the fixed SAS, followed by readjusting the throttle position sensor. Unable to find a pinout of a 2G OBD II connection, I ran a ground tester from the pin "1LE" suggested; pin #1. No voltage. Cleared the ECU memory by disconnecting the negative post on the battery for 1 minute. After I started the car, timing read 18-22 degrees advance, and RPMs were at 1500. After I grounded pin #1 on the OBD connector and the brown ignition timing plug by the firewall, the datalogger displayed 5 degrees advance timing, and the RPMs came down to 1100. My short term fuel trims were whack; 13-17% very lean. I tried to adjust the BISS screw but found that it was completely bottomed out. What?!? So I couldn't lower my RPMs at all. Turned the car off, disonnected all grounding plugs and restarted.

After about 5 minutes the RPMs stabilized around 1000, and STFT came down to 8-10%. Forgot to check timing.

Now when I shift my automatic transmission into D, the RPMs drop to 850-900. Idle is very quiet and stable now. It doesn't stumble on deceleration anymore. This is a lot better than it has been but my RPMs are still not within OEM spec (750).

What can I do? My BISS has nowhere to go!

 

[woooop]

Can i adjust the biss without a Scan Tool or if not where can i get one .I just built a 6 bolt and ill need to adjust the biss ?

 

[jabinya]

Here is a thread explaining how to adjust the 2G BISS without a scan tool.

http://www.dsmt uners.com/forums/showthread.php?t=234723

 

[woooop]

that thred didnt help

 

[jabinya]

If your running a 2G ECU this should work;

Well, for those that might be reading this that have a '95, it's easy... For '96+, a MUT-II is the only "official" way, but if you can develop your own way, lots of people would appreciate it!

Anyways, quick overview for '95 owners (going completely from memory here, VERIFY with a manual before attempting! This is JUST a rough overview with some helpful hints!)...

1) Use a logger and find out how far off your stock tach is (Mine reads 850 when the ECU reports 750). VERY important for getting it just right! I didn't do this the first time, trust me, it's important!

2) Ground the timing plug (per the manual). Brown plug on the firewall, IIRC?

3) Ground the appropriate pin in the the OBD-2 connector. I THINK it was pin 1? VERIFY this with the manual! Once you do that, DOUBLE and TRIPLE check to make sure you understand which pin is the proper one on the plug! You can do a LOT of damage if you ground the wrong one! A MUT-II automatically grounds this pin when plugged in, but a standard ISO OBD-2 scanner does NOT!

4) Start up car and twiddle the BISS until you get your calibrated 750 rpms (on my car, a tach indicated 850).

5) Let car idle for 10 minutes to make sure it stays there.

6) Shut 'er down and unplug all your stuff! May still idle surge the first couple of trips as the ISC is NOT reset to 0 by the procedure (could be more trips if you're really incredibly far off I suppose?). It WILL have to relearn the ISC setting, but the new ISC setting will be right in the middle! You could try resetting the ECU to force a 0 ISC setting, but then your STFT and LTFT get whacked and that can cause issues too if your car is not 100% stock I also use RTV to keep my BISS in place. The stock cap leaves enough gap that the BISS can back itself out some over time (just enough to mess up the idle).