GVR-4 ECMLink ISC live data

[Elpizer2]

I am running maft+ 3 inch gm maf ecmlink, the thing is that I'm trying to tune the idle but I don't see the ISC live data, also can't add

ISC position
Learn idle value

Why?

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[Elpizer2]

How to remove/replace pins in harness connectors

Disclaimer: I am not responsible for anything done to your car/equipment. Use this information at your own risk. It is possible to damage components if you don't know what you are doing and don't use common sense. Keep in mind do these things at your own risk!That being said, lets get onto the...

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Ok I just swapped pin 6 to pin 14, and the idle switch starts reading and the ISC position starts to move as well.

When I press the accelerator pedal, Idle Switch goes to 0, the go back to 1 when off.

However the ISC position goes straight to 120 or 0 when I try to adjust the BISS screw. If open it goes to 0, if tight it goes to 120.

I tried to change ignition timing map and ISC map to see if something happens but I don't know. Also when I turn on the A/C, it does not compensate.

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[steve]

Ok I just swapped pin 6 to pin 14, and the idle switch starts reading and the ISC position starts to move as well.

When I press the accelerator pedal, Idle Switch goes to 0, the go back to 1 when off.

However the ISC position goes straight to 120 or 0 when I try to adjust the BISS screw. If open it goes to 0, if tight it goes to 120.

Great, one problem solved. The BISS screw isn't intended to be open or closed so I'm not sure I follow. It usually if you don't have air leaks winds up somewhere between 1.5 and 2.5 turns back from the bottom. The car need to be at temp in closed loop before you can correctly set it.

ISC position 0 is ISC fully closed and 120 is the max open for a 90 ECU. Normal idle position at temp is about 30 steps.

I tried to change ignition timing map and ISC map to see if something happens but I don't know. Also when I turn on the A/C, it does not compensate.

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You can log the AC switch to check that the ECU sees it.

 

[Elpizer2]

Great, one problem solved. The BISS screw isn't intended to be open or closed so I'm not sure I follow. It usually if you don't have air leaks winds up somewhere between 1.5 and 2.5 turns back from the bottom. The car need to be at temp in closed loop before you can correctly set it.

ISC position 0 is ISC fully closed and 120 is the max open for a 90 ECU. Normal idle position at temp is about 30 steps.



You can log the AC switch to check that the ECU sees it.

Ok how do I know that the is on closep loop mode?

Yes the ECU seed the A/C switch On/Off

 

[jed344]

Yes as you found out those pin's need swapped when a 90 and 91+ ECU or vice versa.

For the ISC, it will move but not jump to max's instantly I have seen. I shoot for 35-45 ISC position. I generally will get the car up to temp, then adjust BISS and let idle for 30 seconds or so. Shut the car off and wait for ECU to click off. Then restart the car and first 30 seconds or so the ISC will move quickly. I keep doing this process until I get it where I want it.

Over the years i have tried many different ways to set it and everything ends up taking a while to get it correct anyway. This method takes around 10 minutes. There was something to do with right when the car starts after ECU has been of that the long term idle adj wont be taken into account so the ISC moves rapidly right away I think. I did this last night on a car at the shootout that was idle surging due to his BISS being almost a turn and a half to open so ISC would max out closed.

From my experience the ISC generally will not go lower then 15-20 when closing even though technically they can go to zero I rarely see that. When I see ISC numbers under 25 at idle the car usually ends up surging same as when i see ISC over 60 at idle I see them stall.

I would make sure the DA tables for ISC are factory and get it set right with the BISS. I generally only have to modify the ISC table in DA when its a e85 car with very aggressive cams on cold start. Then I will add ISC so they idle till they warm up some.

 

[Justin DuBois]

Ok how do I know that the is on closep loop mode?

Yes the ECU seed the A/C switch On/Off

You are logging it - ClosedLoop. 0 or 1

 

[Elpizer2]

You are logging it - ClosedLoop. 0 or 1

OK but
0 = Open Loop
1 = Closed Loop

? I'm a little confused

I would make sure the DA tables for ISC are factory and get it set right with the BISS.

I need the ISC DA factory table because I modified it. Where can I find it?.

It's weird because when I unscrew the BISS, the ISC goes to 0 totally closed

 

[steve]

In the case of binary options 0=false, 1=true. Since this parameter is called ClosedLoop, when it's = 1 then closed loop is true.

When you unscrew the BISS you let more air bypass the throttle butterfly and the ISC closes down (goes to 0) to counteract that.

There is a arrow pointing in both directions on the DA pages. That allows you so quickly flip between your settings and the stock settings. The also provide a “reset to stock” button in each of the Direct Access tabs that you can use to revert those tables to stock and then save then to the ECU.

 

[Elpizer2]

In the case of binary options 0=false, 1=true. Since this parameter is called ClosedLoop, when it's = 1 then closed loop is true.

When you unscrew the BISS you let more air bypass the throttle butterfly and the ISC closes down (goes to 0) to counteract that.

There is a arrow pointing in both directions on the DA pages. That allows you so quickly flip between your settings and the stock settings. The also provide a “reset to stock” button in each of the Direct Access tabs that you can use to revert those tables to stock and then save then to the ECU.

Ok, I have this:

1- Ecu is controlling the closing of the ISC, because when I unscrew the BISS the data logs shows how ISC Position starts going down and RPM goes down slowly.

However,

2- When I screw the BISS, the datalog shows that the ISC Position goes up to 120 but the car does not rev up.

So the ISC is not responding to rev up the vehicle.

Could you guys confirm me again the cables to swap for the ISC please, I just swapped 67 to 68 I think but 58 59 are stock like 91 wiring.

Or can I swap 58 and 59 ?


If not I think I have a bad driver but the ecu doesn't have the damage signs on them.

 

[steve]

Could you guys confirm me again the cables to swap for the ISC please, I just swapped 67 to 68 I think but 58 59 are stock like 91 wiring.

Or can I swap 58 and 59 ?

Again, I don't believe you should be swapping any of the ISC pins from the factory position in this harness.

GVR-4 - ECMLink ISC live data

I am running maft+ 3 inch gm maf ecmlink, the thing is that I'm trying to tune the idle but I don't see the ISC live data, also can't addISC position Learn idle valueWhy?You must be registered to see element.

www.dsmtuners.com

So, if you have I'd put them back and see how it behaves.

 

[Elpizer2]

Again, I don't believe you should be swapping any of the ISC pins from the factory position in this harness.

GVR-4 - ECMLink ISC live data

I am running maft+ 3 inch gm maf ecmlink, the thing is that I'm trying to tune the idle but I don't see the ISC live data, also can't addISC position Learn idle valueWhy?You must be registered to see element.

www.dsmtuners.com

So, if you have I'd put them back and see how it behaves.

Again, I don't believe you should be swapping any of the ISC pins from the factory position in this harness.

GVR-4 - ECMLink ISC live data

I am running maft+ 3 inch gm maf ecmlink, the thing is that I'm trying to tune the idle but I don't see the ISC live data, also can't addISC position Learn idle valueWhy?You must be registered to see element.

www.dsmtuners.com

So, if you have I'd put them back and see how it behaves.

Yes but check this out, I'm confused about this
https://www.dsmtuners.com/threads/using-91-isc-in-90-tb.515280/
https://www.dsmtuners.com/threads/using-91-isc-in-90-tb.515280/

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[Elpizer2]

I made a conversion harness for my 90 so I could use a 91+ TPS. Works fine in my car, you are in the right track. I didn't want to hack my harness. I did the same thing with a Arc2 box and converted it to a 90 plug also. ​

I'm trying to make this conversion, I have a 90 dsm ecu and 91+ wiring harness, 91+ N/T Big throttle body 91+ ISC black plastic one.

I swapped pin 14 to pin 6 for Idle position switch, but

Do I need to swap pin 58 59 and pin 67 68 as well?

I mean pin 59 to 58 position and 58 to 59

67 to 68 position and 68 to 67 position ???

 

[We're on Boost]

Yes but check this out, I'm confused about this

If your harness wiring, ecu, and ISC motor are some mix of 1990 and 1991+ parts (not all one or the other) then you might need to reverse the harness wires for one of the stepper motor field coils. I haven't read your thread enough to know if you have this mix or not.
But you can check for correct motion of the ISC motor like I did in this video:

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You do have to be careful doing this check, because if the pintle is extending but not retracting, and you cycle it back and forth several times, the pintle will shoot right out of there like a torpedo after about the 3rd cycle, like it did for a guy we were talking to in here about a year ago or so. I can find that thread for you if you want to see it. In his case I think we decided that the driver in the ecu that does the retract was busted, so only the extend was working!!

On my car, I had 1990 everything except for the ISC which was a new one for 1991 and later, so I had to reverse (swap) my 2 harness wires for one of the field coils.
I have a thread for that, link to it at the bottom of the description field on the YouTube video.

But Steve is saying he doesn't think you need to reverse anything.
I see in the other thread you have going for this: "I have a 90 dsm ecu and 91+ wiring harness with 91+ ISC black plastic one." I don't know if this particular combination needs a wire swap or not. I think you should just check it like I show in my video.

Know this for your checking:
Logs show ISC steps (Position) go to 120 when you first turn the key on (engine cold). Then they go to 90 when you turn the key off. That is normal. That 30 steps makes the pintle move about .040 to .060 inches, as near as I can measure it (about 1 to 1.5mm).
Increasing steps (like going from 90 to 120) retracts the pintle. (Increases airflow to the engine)
Decreasing steps (like going from 120 to 90) extends the pintle. (Decreases airflow to the engine)

 

[steve]

On my car, I had 1990 everything except for the ISC which was a new one for 1991 and later, so I had to reverse (swap) my 2 harness wires for one of the field coils.
I have a thread for that, link to it at the bottom of the description field on the YouTube video.
But Steve is saying you shouldn't need to reverse anything so I guess your components are all 1991 and later stuff?

Your case is exactly when I think you need to swap to fix it because the 90 car's harness/ISC is wired differently than the later cars. So when you put a 91+ TB/ISC on a '90 car you have to change the two wires to get the coil order correct with the new ISC.

What I think I said was that I've used '90 ECUs in 91+ cars and don't remember having to swap any ISC wires to make the '90 ECU drive the 91+ ISC correctly and since that's what he's doing I don't think he needs to swap any ISC wires.

It's possible that my memory is wrong. My wife tells me I'm wrong all the time.

@Elpizer2 please stop dragging old posts up to comment on and keep everything here so we don't have to clean them up.

 

[We're on Boost]

Your case is exactly when I think you need to swap to fix it because the 90 car's harness/ISC is wired differently than the later cars. So when you put a 91+ TB/ISC on a '90 car you have to change the two wires to get the coil order correct with the new ISC.

What I think I said was that I've used '90 ECUs in 91+ cars and don't remember having to swap any ISC wires to make the '90 ECU drive the 91+ ISC correctly and since that's what he's doing I don't think he needs to swap any ISC wires.

It's possible that my memory is wrong. My wife tells me I'm wrong all the time.

Oh ok.
What about this then: He says he has a 1990 ecu, 1991+ harness, and 1991+ ISC.
I guess we don't know for sure then if he should be ok with that without swapping any wires?
I figure he should just test it to find out for sure, which was the main reason for my post #37 above.