ECMlink 1G ECMLink V3 Idle issues once up to temp

[Chiefsublime]

So recently I've been dealing with some really annoying idle surge/ISC/lean idle issues.

I thought I had it all worked out by switching some parameters back to stock/recommended. I replaced the ISC as well. It had been doing it right upon start up, but after swapping it out. it started idling good for a while. Then started doing it again. I'm about to say screw it and install a block off plate, but I figured I'd get some input from others more advanced in tuning knowledge.

I went through the checklist as directed to get link/SD tuning set up basics and have (had) the global, dead time fuel trims dialed in. I did recently replace my turbo with a 60/62, but since the issue is only idle related not WOT tuning I'd say it's pretty unlikely to be related. Current set up is 2.3l stroker, BC 280 cams and Ti top end goodies, 1700cc ID's, 450lph, Fuel lab AFPR, Turbonetics BB 6062 T3, v3, LC-1 WB Stock location (NB sim), went back to stock TB/ISC. Had been S90 w/ISC block off plate running 3000GT ISC via vac ports on JMF IM, GM IAT, Omni 4 bar, there's honestly not much stock, but just trying to list the relevant items.

I've done boost leak tests, motor is healthy, Done all of the recommended tests, all check's out.

Some background when this was worse it would rev between 1500-2200rpm. BISS all the way in with no affect. I got it back into range this morning before it started acting up again once up to temp as you'll see in log. ISC was acting like it should. Then once it reached temp it was like it just cut out. Does this sound like I got another bad ISC? Should I just block it off again and say to hell with the ISC all together? It's Driving me nut's!! I've owned/own many DSM's. So I'm familiar with the whole I just wanna drive the bisch. This is my first ECMLink car which I love after getting over the learning curve. I just don't know if I'm just missing something. So maybe a fresh set of eye's or someone with more tuning exp can see something I don't?

Any help is def appreciated!! TIA!

 

[DSMPT]

BISS allthe way in with no affect

This ^.
This indicates that the engine is getting excess air at idle. Most likely you have vacuum leak or improper stop screw (IPS position)/throttle cable adjustment that cause the throttle plate open more. I would start from looking for vacuum leak and adjusting the throttle body properly.

 

[Chiefsublime]

This ^.
This indicates that the engine is getting excess air at idle. Most likely you have vacuum leak or improper stop screw (IPS position)/throttle cable adjustment that cause the throttle plate open more. I would start from looking for vacuum leak and adjusting the throttle body properly.

Did you look at the log? If you control q to remove all the noise and just look at the ISC info. You can see it is working like it should and then once it gets up to temperature it just drops off completely. IDK if you think this in lieu of that or what would the relationship between those two things be? Just trying to get a better understanding of your input.

You're probably right through. I will test for vacuum leaks.

Thanks!

 

[pauleyman]

So recently I've been dealing with some really annoying idle surge/ISC/lean idle issues.

I thought I had it all worked out by switching some parameters back to stock/recommended. I replaced the ISC as well. It had been doing it right upon start up, but after swapping it out. it started idling good for a while. Then started doing it again. I'm about to say screw it and install a block off plate, but I figured I'd get some input from others more advanced in tuning knowledge.

I went through the checklist as directed to get link/SD tuning set up basics and have (had) the global, dead time fuel trims dialed in. I did recently replace my turbo with a 60/62, but since the issue is only idle related not WOT tuning I'd say it's pretty unlikely to be related. Current set up is 2.3l stroker, BC 280 cams and Ti top end goodies, 1700cc ID's, 450lph, Fuel lab AFPR, Turbonetics BB 6062 T3, v3, LC-1 WB Stock location (NB sim), went back to stock TB/ISC. Had been S90 w/ISC block off plate running 3000GT ISC via vac ports on JMF IM, GM IAT, Omni 4 bar, there's honestly not much stock, but just trying to list the relevant items.

I've done boost leak tests, motor is healthy, Done all of the recommended tests, all check's out.

Some background when this was worse it would rev between 1500-2200rpm. BISS all the way in with no affect. I got it back into range this morning before it started acting up again once up to temp as you'll see in log. ISC was acting like it should. Then once it reached temp it was like it just cut out. Does this sound like I got another bad ISC? Should I just block it off again and say to hell with the ISC all together? It's Driving me nut's!! I've owned/own many DSM's. So I'm familiar with the whole I just wanna drive the bisch. This is my first ECMLink car which I love after getting over the learning curve. I just don't know if I'm just missing something. So maybe a fresh set of eye's or someone with more tuning exp can see something I don't?

Any help is def appreciated!! TIA!

If the car steady idles at anything over 1500 you either have a problem with the idle position switch or the throttle isn't really closed. Given the comments of ISC behavior I'm inclined to agree you need to check throttle cable and throttle stop. Do you have the intake manifold ground at the throttle body? This is required to get the idle position switch to work. A properly functioning system will cut fuel at 1500rpm if idle position is closed. It's this same thing that causes idle surging when other things are misadjusted.

 

[We're on Boost]

Does this sound like I got another bad ISC? Should I just block it off again and say to hell with the ISC all together?

I would install a bypass plate, not a blockoff plate. A bypass plate blocks off only the FIAV but the ISC still functions fully.

I'm looking at ThrotPos, RawThrotPos, IdleSw, and IdleSwPin, and I see that you have turned on Simulate Idle switch from TPS.
Also you have turned on Disable idle switch while moving.
I have no experience with turning off the idle switch while moving. I leave that one un-checked.

When you have Simulate Idle switch from TPS turned on, your IdleSw should be a 1 whenever RawThrotPos is 34 or less. You do have some places (very few) in the log where RawThrotPos is 34 or less, and if your MPH is 0, then your IdleSw is 1 as it should be. This means that your simulated idle switch is "working". The rest of the time your IdleSw is 0 because either you are moving, or else your RawThrotPos is more than 34.

I would try a bypass plate. I know, Minnesota gets cold, I would try it anyway to see if it makes things better. Fortunately you don't have a 1990 throttle body. Or do you?
What brand and part number is the ISC that you have in it now?

 

[Chiefsublime]

So I'm not 100% what TB it is, but I think it might be a non-turbo throttle body. Because it doesn't have the elbow thingy like most of them. I think it's also a little bit larger opening then the turbo models. I do have multiple other throttle bodies as well as iscs. I went from the s90 with the block off plate, but I was running the external ISC essentially.
So a little update on this. I just unplugged the ISC yesterday and it seems to have stabilized the idle. There is one other issue which I forgot about. As well as a more recent one. I've been been having issues starting after I drive it for a while. It doesn't want to start again. So I have to either let it cool off or push start it. The other thing is when I come to a stop if I just shift to neutral or push the clutch in oftentimes the engine will die. If I leave it in gear and or down shift to keep the revs up til I I get closer to idle. It will keep it running. I don't know if that makes sense or not, but basically when I'm driving around if I just push the clutch in and come to a stop it'll have a tendency to die. The hot start issue is pretty recent. The other issue I've been having since I started using ecmlink. So that has been with different turbos, injectors, throttle bodies, manifolds, etc etc.

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[We're on Boost]

So I'm not 100% what TB it is, but I think it might be a non-turbo throttle body. Because it doesn't have the elbow thingy like most of them. I think it's also a little bit larger opening then the turbo models. I do have multiple other throttle bodies as well as iscs. I went from the s90 with the block off plate, but I was running the external ISC essentially.
So a little update on this. I just unplugged the ISC yesterday and it seems to have stabilized the idle. There is one other issue which I forgot about. As well as a more recent one. I've been been having issues starting after I drive it for a while. It doesn't want to start again. So I have to either let it cool off or push start it. The other thing is when I come to a stop if I just shift to neutral or push the clutch in oftentimes the engine will die. If I leave it in gear and or down shift to keep the revs up til I I get closer to idle. It will keep it running. I don't know if that makes sense or not, but basically when I'm driving around if I just push the clutch in and come to a stop it'll have a tendency to die. The hot start issue is pretty recent. The other issue I've been having since I started using ecmlink. So that has been with different turbos, injectors, throttle bodies, manifolds, etc etc.

Good pic of the ISC. I think it's from a 90's Mitsu 3000 GT. And I think it's very old. The replacement ISCs for those cars don't look like this.
Check it out, here's a little help sheet from 3si org which specializes in these cars.

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So maybe the whole throttle body is from a 3000 GT.
The current replacement ones, take a look here in Rock Auto, Mitsubishi, 1996, 3000GT, V6 turbo, fuel and air, idle air control.
You'll see models like the Standard AC99 and the Wells 2H1086.
I don't know what happens when you try to run one of these with whatever ecu you have.

 

[steve]

It's not a 90 TB, they don't used that type of ISC and the one they do use is positioned differently. The 91+ ISC's were the same on the DSM and on the 3S platforms. They all had the same problem of the coils shorting out and blowing the ECU drivers. The later black plastic ISC are the upgraded replacement and they don't seem to do that.

Here's what a 90 Turbo TB looks like.

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A 90 ISC

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A 91+ Turbo TB

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Since it looks like it has a lip on the front that the coupler is clamped onto it's likely a NT TB.

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[Chiefsublime]

It's not a 90 TB, they don't used that type of ISC and the one they do use is positioned differently. The 91+ ISC's were the same on the DSM and on the 3S platforms. They all had the same problem of the coils shorting out and blowing the ECU drivers. The later black plastic ISC are the upgraded replacement and they don't seem to do that.

Here's what a 90 Turbo TB looks like.

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A 90 ISC

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A 91+ Turbo TB

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Since it looks like it has a lip on the front that the coupler is clamped onto it's likely a NT TB.

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Yep, I'm pretty sure I remember pulling it from a NT eclipse at the junk yard. I liked that it had the coupler lip as one piece and I believe a slightly larger throttle plate/opening.

 

[dwb]

Too much air bypassing the throttle plate = idle surge.
Do you have any nipples on the TB looped? Some other things to check would be the FIAV (via bypass plate or you can close the passage by opening the freeze plug and twisting the valve behind it closed), a leaky or improperly adjusted BISS, disconnected or leaky vacuum line(s), improperly adjusted throttle cable, improperly adjusted idle stop switch, malfunctioning ISC, or leaky intake gaskets.

I can't look at your log at the moment, but it sounds like you are simulating the idle switch. Have you tried using the idle stop switch instead? Have you verified the adjustment of your TPS?

A proper boost leak test should show any vacuum leaks introducing unmetered air, but doesn't show leaks with the the ISC, FIAV, or looped vacuum line.

 

[Chiefsublime]

No, I tested for vacuum leaks (not the same as boost leaks test, but either way I'm running full Speed Density so...) actually it was kind of the opposite in a way. I had the BISS screwed all the way in (too far in to reach set idle speed), but had idle speed set higher than stock in link. Which is why it looked like my ISC wasn't working. So I backed the BISS out about halfway till the ISC started working again. I also adjusted the idle air clamp as per the recommended in the ECM Link forum or website. Idles good now! So basically it wasn't getting enough air to reach the idle speed ECM Link was asking for. Anyway problem solved. Thanks