1G TB on 2G...BISS adjustment without scan tool?

[ProjectTwin]

I swapped a 1G TB onto my 2G, the idle is around 550 or so. I'd like to adjust it up to 750 but don't have the scan tool.

Is there a way to adjust idle without the computer holding idle as I've read on VFAQ?

The VFAQ covers the 1G (using a jumper) and the 2G (using the scan tool), but what's the deal when you've done the swap?

Is there a way to make an adjustment without the scan tool?

I'm lost here...

 

[1fast97gsx]

why don't you just adjust it and let the car run for a while ... then look at the tach and see where it's at now. Then adjust again accordingly??

 

[ProjectTwin]

'cause it's at the paint shop.

I'm reading, wondering if there's a "proper" procedure to go through.

 

[Artago]

Bring this back from the dead because I can't find the answer.

How do you do a BISS adjustment without the Scan tool so the ECU hold the IAC (ISC) at a certain step.

Can DSMlink do it?

Thnaks,

Tom

 

[romeen]

Honestly, I just did it by trial and error after driving over the course of a week. This may not be the ideal or the quickest way but it worked for me. My idle is steady right around 750rpm, no surge or driveability issues.

 

[Artago]

Honestly, I just did it by trial and error after driving over the course of a week. This may not be the ideal or the quickest way but it worked for me. My idle is steady right around 750rpm, no surge or driveability issues.

What do you mean trial and error? I have my BISS set right now and I have the following:

1. Cold idle around 700-800
2. Hot idle 800-1100
3. Car stalls when I pull it out of gear at higher RPM (like 3000+ RPM)
4. The RPMS drop (like 200-500 RPM) and stall 50% of the time when pressing clutch (worse when cold)

Should I back the BISS out a bit?
Did you disconnect the ISC (IAC) when doing this?

Thanks Romeen,

Tom

 

[dj_remy]

What do you mean trial and error? I have my BISS set right now and I have the following:

1. Cold idle around 700-800
2. Hot idle 800-1100
3. Car stalls when I pull it out of gear at higher RPM (like 3000+ RPM)
4. The RPMS drop (like 200-500 RPM) and stall 50% of the time when pressing clutch (worse when cold)

Should I back the BISS out a bit?
Did you disconnect the ISC (IAC) when doing this?

Thanks Romeen,

Tom

Heh, this sounds horribly familiar to my issues right now, so awating an answer as well, need to adjust my BISS I know, but no scan tool, prob started after an intake install.......

I'll try the trial and error technique, but whats too high you think, 900,1000?

 

[Artago]

Heh, this sounds horribly familiar to my issues right now, so awating an answer as well, need to adjust my BISS I know, but no scan tool, prob started after an intake install.......

I'll try the trial and error technique, but whats too high you think, 900,1000?

I'm already surging between 850-1100.

I'm going to install an FIAV bypass plate and test for vac/boost leaks (I'm almost positive I have some).

Tom

 

[romeen]

What do you mean trial and error? I have my BISS set right now and I have the following:

1. Cold idle around 700-800
2. Hot idle 800-1100
3. Car stalls when I pull it out of gear at higher RPM (like 3000+ RPM)
4. The RPMS drop (like 200-500 RPM) and stall 50% of the time when pressing clutch (worse when cold)

Should I back the BISS out a bit?
Did you disconnect the ISC (IAC) when doing this?

Thanks Romeen,

Tom

I just re-read my post and realized I wasn't very clear on it. I was having issues with increased idle speed after the motor had warmed up. Turns out my throttle cable was too tight. There is a method for adjusting it to give the most possible slack when the throttle is closed. But I prefer having as little slack or free play in the cable as possible while still allowing the throttle plate to remain closed when warm. So everyday I drove the car I would pay attention to the idle speed when I was stopped at lights and when I got home I would adjust the cable as needed and then the BISS to get the idle where I wanted it. It seems like after an adjustment the idle would move around a bit but settle down and remain steady after a while. Maybe the ECU was adjusting to the new settings (speculation)?

Like I said, I'm sure the recommended way is a better, easier way of doing it. But I didn't have the scan tool and this way did end up working for me.

I'm not sure about the stalling but it might be related to the TPS. When I swapped to a 1G TB I used the RRE method to adjust it and it works great. The logger shows 0% throttle position at idle and 97% at WOT. Just something to consider.

Here is a post that I found helpful:

http://www.dsmtuners.com/forums/151021480-post6.html

 

[dj_remy]

I'll try that this monday to see if it helps me out at all, getting pocketlogger next weekend so that ought to help out alot, thanks.

 

[Artago]

I've already adjusted and re-adjusted my TPS... still nothing.

Tom

 

[romeen]

Are you sure that the throttle cable isn't too tight? The higher idle when the motor is warm can cause that. Check the link I gave in post #9, there is some good info there.

Have you resistance tested the ISC coils?

Do you have a logger to check throttle position (compare cold vs. warm engine) and coolant temps?

 

[Artago]

Are you sure that the throttle cable isn't too tight? The higher idle when the motor is warm can cause that. Check the link I gave in post #9, there is some good info there.

Have you resistance tested the ISC coils?

Do you have a logger to check throttle position (compare cold vs. warm engine) and coolant temps?

The cable was tight and I loosened it (a few weeks back). It fixed 99% of the high idle. Can still idles a little higher when warm. IE: cold idle 700-800 RPM, hot idle 800-1100 RPM.

TPS cold and hot is 0-1% via pocketLogger.

Coolant temps are high but under control. 199-222 (cruise and idle depending on outside temp). I'm working to resolve this one soon.

The BIGGEST problem is the car stalling out when I push the clutch in, ESPECIALLY when the RPMs are higher. I come to a stop sign press the clutch and the car dies. The only thing I can do is press the clutch and throw it into neutral and RELEASE the clutch before the RPMs drop to the point where the car stalls. If I release the clutch quickly then it only stalls about 5% of the time (worse when cold). If I press the clutch and HOLD it while the RPMs drop then they will drop until they hit 0 and the car dies.

This is really REALLY annoying because when I'm stuck in traffic then the car dies on me every 50 feet and I have to start it back up.

Any ideas?

Tom

 

[romeen]

If loosening the throttle cable helped then maybe try loosening it just a bit more. It still might be a little too tight. Here is one thing to try. Next time your motor is warm and idling high, pop the hood and try to manually close the throttle plate. Just push on the throttle lever so that you are taking up any possible slack in the throttle cable. If the idle drops then the cable is still too tight.

Also, in response to your previous question, no I did not disconnect the ISC when adjusting the BISS. Have you actually used an ohmeter to test the resistance of the ISC coils? Maybe remove the ISC and clean the carbon deposits off of the tip. A little bit of brake cleaner and a toothbrush will take care of it. Maybe even clean out the TB itself.


I don't know if this helps but I found this thread of someone with a similar problem:

http://www.dsmtuners.com/forums/problem-diagnosis/298331-car-dies-when-clutch-maybe-flywheel.html

It easy enough to increase your idle so it may be worth giving it a shot. Just back the BISS out a bit.

 

[dj_remy]

+1 on cleaning TB, again, another Monday project.

I'm having the same problem but mines an auto, so no pushing in clucth, when I come to a slow/stop my idle shoots down and stalls 15% of the time, more on hot days,

Trying the ISC coil cleaning/testing and TB cleaning/testing and BISS adjust on Monday, any tips? new gaskets for TB if removing? preffered cleaner? stuff to watch out for?

 

[dj_remy]

Sorry to Double post, but backed my BISS out a few turns and idle surge was fixed, plus its a bit more responsive, so thanks guys.

And didn't use a scannner tool.

 

[spyderdrifter]

Honestly, I just did it by trial and error after driving over the course of a week. This may not be the ideal or the quickest way but it worked for me. My idle is steady right around 750rpm, no surge or driveability issues.

When you started your trial and error, was there a noticable change in the idle the first time you adjusted the biss? I got a 3k rpm idle problem and decided to try to adjust it based on this posting's discution. Mine's a '95 gst, 6 bolt block, 7 bolt head. Stock ecu, and I don't have any scan tools, loggers or anything else for programming. Just gotta go about setting the biss the long hard way. Any help would be great. Thanks.

 

[turboglenn]

WEll, romeen had good advice, and to add on that a lot of tiems the cable being too tight is at the cruise module. I solved all my srging (even with aftermarket ECU) by loosening the lock nuts on the in and out cables of the cruise anhd slacking the cables up by a few turns.

But for BISS adjustmetn without scan tool one thing i've found that works is to disconnect the idle controll motor (sometimes you have have to pull it out and spin it till it's extended enough to block off it's supply of air completely (i can set mine to "0" in my software) then adjust the idle screw untill you've got between 600 and 800 RPM and then hook the ISC motor back up.. and if it doesn't learn the idle down to the levels they should be at consistantly, then adjust the screw slightly in either direction to copensate.. But FIRST make sure to check them cables.. even i said "mine can't be too tight' and put it off for ages..well i waited ages too long to try it as i haven't had the headache in years now

 

[romeen]

When you started your trial and error, was there a noticable change in the idle the first time you adjusted the biss? I got a 3k rpm idle problem and decided to try to adjust it based on this posting's discution. Mine's a '95 gst, 6 bolt block, 7 bolt head. Stock ecu, and I don't have any scan tools, loggers or anything else for programming. Just gotta go about setting the biss the long hard way. Any help would be great. Thanks.

Unless the BISS is completely missing or has no o-ring it sounds like there is something else wrong other than just the BISS being out of adjustment. As mentioned, if it only does the high idle after the motor has warmed up (even more so on hotter days) then start by loosening up the throttle cable a bit. If the idle is high all the time then I would do start by doing a boost leak check. A vacuum leak especially around the TB can give you a high idle whether motor is cold, hot, etc.

Unfortunately, you can only expect the BISS to do so much. If you rely on it too much and end up way out of range of where it should be then the ECU is going to try to compensate by using the ISC motor. If the ISC is always working at the low or high ends of it's range then not only can you burn out the ISC's individual coils but I've read that this in turn can also damage the ECU itself (at least on a 1G but I would think this is probably true for 2G's as well).

With an idle speed of 3K I would start by looking for vacuum leaks by doing a boost leak test (don't forget to check for leaking TB shaft seals by opening/closing the throttle plate while doing the test). Make sure the throttle cable is adjusted properly. Test the ISC motor by checking resistance across it's individual coils (DmTaLoN's Idle Speed Control Test/Fix Page!). Use the BISS for smaller adjustments of idle speed once you've ruled out other causes.

Unfortunately, the trial and error method has many flaws but can be successful if making small, repeated changes to the BISS and then giving the ECU some time to adjust, etc.

 

[spyderdrifter]

WEll, romeen had good advice, and to add on that a lot of tiems the cable being too tight is at the cruise module. I solved all my srging (even with aftermarket ECU) by loosening the lock nuts on the in and out cables of the cruise anhd slacking the cables up by a few turns.

But for BISS adjustmetn without scan tool one thing i've found that works is to disconnect the idle controll motor (sometimes you have have to pull it out and spin it till it's extended enough to block off it's supply of air completely (i can set mine to "0" in my software) then adjust the idle screw untill you've got between 600 and 800 RPM and then hook the ISC motor back up.. and if it doesn't learn the idle down to the levels they should be at consistantly, then adjust the screw slightly in either direction to copensate.. But FIRST make sure to check them cables.. even i said "mine can't be too tight' and put it off for ages..well i waited ages too long to try it as i haven't had the headache in years now

So how can I tell for dure if my throttle cable is too tight? I've concidered that possibility, but always dismissed the idea since there's been slack on it from where it bolts to the manifold and where it attaches to the throttle plate. Also, how can I tell if it's the cruise module? By nuts on the cruise in and out cable, are you refering to the 2 nuts that lock it onto the brackets holding the pulleys for the cables? If so, I never concidered those and will give that a shot. How do I spin the part on the ISC without breaking it?

Unless the BISS is completely missing or has no o-ring it sounds like there is something else wrong other than just the BISS being out of adjustment. As mentioned, if it only does the high idle after the motor has warmed up (even more so on hotter days) then start by loosening up the throttle cable a bit. If the idle is high all the time then I would do start by doing a boost leak check. A vacuum leak especially around the TB can give you a high idle whether motor is cold, hot, etc.

Unfortunately, you can only expect the BISS to do so much. If you rely on it too much and end up way out of range of where it should be then the ECU is going to try to compensate by using the ISC motor. If the ISC is always working at the low or high ends of it's range then not only can you burn out the ISC's individual coils but I've read that this in turn can also damage the ECU itself (at least on a 1G but I would think this is probably true for 2G's as well).

With an idle speed of 3K I would start by looking for vacuum leaks by doing a boost leak test (don't forget to check for leaking TB shaft seals by opening/closing the throttle plate while doing the test). Make sure the throttle cable is adjusted properly. Test the ISC motor by checking resistance across it's individual coils (DmTaLoN's Idle Speed Control Test/Fix Page!). Use the BISS for smaller adjustments of idle speed once you've ruled out other causes.

Unfortunately, the trial and error method has many flaws but can be successful if making small, repeated changes to the BISS and then giving the ECU some time to adjust, etc.

Are you talking about seals on the inside of the TB?

 

[Absit]

This is possibly the worst thread on the BISS to bump. Spend the $50 for your scan tool (2G) and do it right. Just because it seems to be working doesn't mean it's anywhere close to set properly.

Please, new members, do not follow this thread.

 

[spyderdrifter]

Well, thanks to the 2 of you who actualy posted replys intended for helping a fellow DSM owner. I did try to readjust my throttle cable at the pulleys and the idle lowered to about 1500-1600 rpm. But since my car has been sitting awhile, my charging system still isn't charging right, luckly I know why, so I won't be driving it until I fix that problem. I guess I'll take the advice of the one on here trying to lead members away from this post and try to find a scan tool, but aside from his comments, romeen and turboglenn have been quite informitive on the idle issues with DSMs. Thanks for the help.

 

[95g-s-x]

Bring this back from the dead because I can't find the answer.

How do you do a BISS adjustment without the Scan tool so the ECU hold the IAC (ISC) at a certain step.

Can DSMlink do it?

Thnaks,

Tom

Since u have LINK, log isc position, let the engile idle until it gets to operating temp, and slowly adjust the biss until isc position is at 30. .... your biss is now set properly.

I have done this numerous times, and works perfectly fine. It is how they recommend doing it on the LINK forum