General Tuning and NO isc/Iac.

[El Cuervo]

Hey guys what's up?
I have some questions. Is anyone successfully running without the ISC? I deleted the ISC after swapping to a Ford throttle body. I was running a remote mounted ISC but it went bad on me. So I decided to eliminate it and see if I could run without it. I really would like to run without it. But if must, then I will bite bullet, purchase one and install it. I'm ready dreading the install, since there isn't enough space to mount it and where I had it mounted, it was very inconvenient.

Thanks guys.

 

[danl]

The ECU won't know if you removed ISC and will continue to use timing, to the degree it can, for controlling idle speed. However it should go without saying you are limiting the ECU's ability to maintain a high idle when the engine is coming up to temp, the thermo-air valve helps out here, but the ISC makes adjustments on top of that. Also the ecu has no ability to softly bring the engine down to idle speed without an ISC, thus you will have issues with the engine stalling.

 

[El Cuervo]

The ECU won't know if you removed ISC and will continue to use timing, to the degree it can, for controlling idle speed. However it should go without saying you are limiting the ECU's ability to maintain a high idle when the engine is coming up to temp, the thermo-air valve helps out here, but the ISC makes adjustments on top of that. Also the ecu has no ability to softly bring the engine down to idle speed without an ISC, thus you will have issues with the engine stalling.

Danl. Thanks for replying.
Exactly what you say. Thus why I was asking if anyone had successfully ran without ISC. Or if anyone had found a way to successfully run with the ISC and be happy. I have read some old threads where people were saying that ECMLink was able to emulate the ISC, just like it can emulate the idle switch and is able to compensate for a TPS that is not perfectly adjusted. So I tried looking for such option on ECMLink but didn't find anything. Maybe it was an option that was offered in a previous firmware version but then was removed? Or maybe it was all just misinformation from people? Who knows.

As I have stated previously, I can bite the bullet and buy another ISC. To me that's not a problem. The problem is removing everything to install it and having to find another place more convenient to mount it. I'm using an aftermarket TB and remote mounting the ISC is a real pain. Even more so to mount it in a convenient place that is easily accessible to service it. My setup is pretty cluttered by the firewall and there is little room for it. This is why I really wanted to eliminate the ISC. Also getting rid of future potential boost leak sources that would be extremely hard to find.

So if anyone has found a way to successfully run without the ISC and is glad that they removed it, please share what you did. It would be very much appreciated.

Thanks guys.

 

[CrackedDSM]

I did it on my 1G with tunerpro. I just completely deleted the entire FIAV and ISC portion of the throttle body with a block off plate, and I never had idle issues honestly. I’d just adjust the BISS screw with the pin on the firewall ground and it would stay there. I was on speed density and the only issue is very occasionally I’d have a high-ish idle when it was cold. But I was an automatic so that never bothered me. On a manual trans car it might’ve been more problematic.


For what it’s worth though, all my subsequent DSMs since then have all had their ISCs. Too nice of a feature to not have.

 

[nathan_spindler55]

On our race galant we had to crack the throttle body just a bit to get a lil more air into the plenum and then make the tps adjustment on link to bring it back into calibration. Works pretty good.

 

[El Cuervo]

I did it on my 1G with tunerpro. I just completely deleted the entire FIAV and ISC portion of the throttle body with a block off plate, and I never had idle issues honestly. I’d just adjust the BISS screw with the pin on the firewall ground and it would stay there. I was on speed density and the only issue is very occasionally I’d have a high-ish idle when it was cold. But I was an automatic so that never bothered me. On a manual trans car it might’ve been more problematic.


For what it’s worth though, all my subsequent DSMs since then have all had their ISCs. Too nice of a feature to not have.

Cracked, what pin is it that you ground to the firewall? And why did you do it?
Thanks man for the reply.

 

[El Cuervo]

On our race galant we had to crack the throttle body just a bit to get a lil more air into the plenum and then make the tps adjustment on link to bring it back into calibration. Works pretty good.

Nathan. I do have a custom "biss" that I rigged in order to fine adjust the ISC that I had. I could use that. But it's also very easy to adjust the TB plate with the adjustment screw and re-sent the TPS.
I'm going to give it a try and see how it performs.
Thanks for replying man!

 

[CrackedDSM]

Cracked, what pin is it that you ground to the firewall? And why did you do it?
Thanks man for the reply.

I told you wrong. Here’s the full procedure from the FSM.

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The diag port it’s talking about is right next to the fuse panel under the steering wheel/drivers side dashboard. The ignition timing adjustment connector is right next to the ABS proportioning valve on the firewall.

 

[nathan_spindler55]

Nathan. I do have a custom "biss" that I rigged in order to fine adjust the ISC that I had. I could use that. But it's also very easy to adjust the TB plate with the adjustment screw and re-sent the TPS.
I'm going to give it a try and see how it performs.
Thanks for replying man!

Also make sure to scale it when done so that you are getting 100 percent when wide open throttle. Our galant wouldn't idle for crap before and now we have a pretty good one. I had to play with that and the biss screw until I got enough airflow to hold it where i wanted and it took a few tries.

 

[El Cuervo]

I told you wrong. Here’s the full procedure from the FSM.

You must be logged in to view this image or video.

The diag port it’s talking about is right next to the fuse panel under the steering wheel/drivers side dashboard. The ignition timing adjustment connector is right next to the ABS proportioning valve on the firewall.

This procedure is to set the ISC? Did you set your idle this same way but with NO ISC?

Also make sure to scale it when done so that you are getting 100 percent when wide open throttle. Our galant wouldn't idle for crap before and now we have a pretty good one. I had to play with that and the biss screw until I got enough airflow to hold it where i wanted and it took a few tries.

How is your idle now and your drivability? Does it stall or any other abnormal behavior?

 

[CrackedDSM]

This procedure is to set the ISC. Did you set your idle this same way but With NO isc?

Yeah. I did it this way to lock timing and it sets the idle speed for the ECU. If you don't, the ECU will try to correct to get it back to the original RPM if you just turn the BISS without this. ECMLink has a checkbox to ground this pin for you, but it's good to know for people without it.

 

[El Cuervo]

Yeah. I did it this way to lock timing and it sets the idle speed for the ECU. If you don't, the ECU will try to correct to get it back to the original RPM if you just turn the BISS without this. ECMLink has a checkbox to ground this pin for you, but it's good to know for people without it.

Thanks man. I'll give it a try and see what I come up with.