General 1G DSMLink ISC has hysteresis?

[rdeis]

Hey all! I just replaced the o-ring on my BISS and tried to adjust the ISC to 30 by tightening and loosening the screw.

I turned it down snug then loosened the screw 1/4 turn at a time and checked the logger.. 0.. 0.. 0.. 0.. climbing, leave it alone.. 120.
Must have gone too far, tighten it 1/4 at a time 120... 120... 120... falling, wait... 0. (!?)

I must have repeated this sequence 10 times, tried longer delays, tried 1/8 increments, I can't get it to stop in the middle.

What am I missing?

 

[pauleyman]

did you ground the check connector?

 

[dwb]

Does it seem like the ISC is actually moving, as in changing the rpm? Because that's similar behavior I was seeing when I was testing an ECU with broken traces. You could have just broken a wire or a pin isn't making contact.

 

[99dsmer4g63]

Tighten the BISS screw down the entire way and then loosen it about 2 - 2.5 turns out as a starting point. Let the car warm up and see where it’s at. Turn a small amount and wait for it to adjust itself.

-Daniel

 

[ItsTwan309]

Check your throttle stop and then cable. I dealt with this for 2 hours on a buddies car a month ago just to find out he never set the stop before installing his tb

 

[steve]

Does DSMLink show that the IPS is switching and that the throttle is closed?
Do you have a solid throttle body ground?
What flavor of ISC do you have? What are the coil resistances.
FIAV active?
Throttle Cable adjusted with the specified slack?
What condition is the ECU in?

 

[rdeis]

Does it seem like the ISC is actually moving, as in changing the rpm?

Not really, no.

Does DSMLink show that the IPS is switching and that the throttle is closed?

Yes and yes.

Tighten the BISS screw down the entire way and then loosen it about 2 - 2.5 turns out as a starting point.

If I tighten it all the way down, the values start moving close to 3/4 turns out, which seems suspicious.

My TODO list:
1> FIAV active (how to check?)
2> measure ISC coil resistance
3> Check throttle cable slack (I think it's OK, will confirm with FSM?)
4> Throttle body ground
5> Test with check connector grounded (Is this the same check connector for setting spark base timing?)

 

[steve]

My TODO list:
1> FIAV active (how to check?)
5> Test with check connector grounded (Is this the same check connector for setting spark base timing?)

1> It's really two questions, it it blocked off or turned all the way in? When the car it cold does it fast idle until it warms up? You might not be able to tell if your idle speed never gets news the programmed setting (or 850 on a stock ECU).

5>

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[rdeis]

1> It's really two questions, it it blocked off or turned all the way in?

I have no intentional mods to the FIAV system. Coolant lines are connected to the throttle body.