Cant get a steady/stable idle from off idle to approx 1700 rpm, Gen 4 LS3 E38

Just like the thread says. Cant get the engine to rev up a bit and hold steady rpm below 1700 RPM.

I am just working out the last of the bugs in the car. It has done this from day one since I installed the TSP Stage 2 camshaft.

I can see the Throttle Control source changed from "Idle" to "Pedal" mode when pressing on the accelerator pedal.

The issue is here that with a very light press of the pedal to get this thing to rev up a few hundred RPM, it does not switch into Pedal mode, but rather stays in idle mode until roughly 1700 RPM. I have included a log but you can clearly see the adaptive idle is pulling spark to drop the idle even though I am actually on the pedal a few percent.

When you watch "Idle Mode" it changes from "Speed Control" to "Follower" at the same time as Throttle Control source changes from idle to pedal mode.

Is there any way to adjust this or any settings I can play with to make the PCM activate pedal mode if it has any kind of throttle input?

The engine idles and drives perfectly . Even when driving at a very low RPM it does not do this.

Idle only.

Check out my log. I've also logged all the Throttle percentage voltages and percentage's.

Attachment 144415



Attachment 144416

Turn off spark smoothing.

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Originally Posted by edcmat-l1

Turn off spark smoothing.

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Spark Smoothing? Is this just a simple on/off deal, or is there tables involved as well?

I will have to take a look when I get home tonight and try it out

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Originally Posted by Allen Vos

Spark Smoothing? Is this just a simple on/off deal, or is there tables involved as well?

I will have to take a look when I get home tonight and try it out

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Well knowing you, you'll probably want to screw with the tables LOL. Sorry, couldn't help myself LOL. Just turn it off.

Attachment 144423

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Originally Posted by edcmat-l1

Well knowing you, you'll probably want to screw with the tables LOL. Sorry, couldn't help myself LOL. Just turn it off.

Attachment 144423

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Ha Ha , Funny guy. So I tried turning the spark smoothing off and it did nothing to fix the issue.

Any other Ideas?

I just don't understand how with any pedal input at all, it would ever revert back to "Idle Mode" or "Speed Control" and allow the adaptive spark idle control to pull spark out with the throttle pedal pressed?

There has to be some relation or setting for this.

Is there some kind of throttle table that ignores low throttle input until a certain throttle percentage is attained?

First, that is 100% spark smoothing activity. If turning it off doesn't fix it you'd have to assume it's because something else is changed that most likely shouldn't be. With no tune to look at it's a guessing game. But I'll say again turning off spark smoothing 100% should fix that problem.

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Originally Posted by edcmat-l1

First, that is 100% spark smoothing activity. If turning it off doesn't fix it you'd have to assume it's because something else is changed that most likely shouldn't be. With no tune to look at it's a guessing game. But I'll say again turning off spark smoothing 100% should fix that problem.

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Well there are things changed for sure as its far from stock lol.

I did post a log but I will post the tune on my lunch break as its on a different computer

You should be able to see in the log how throttle control source switches back to idle mode while the accelerator pedal is being pressed.

I don't think that's right, and I believe that's where the problem lies.

You can see in the log where the adaptive idle pulls spark out to reach the target idle while having pedal input.

Its just going back to idle mode when it shouldn't be

This is the kind of weird crap you get when you go changing things you shouldn't or don't need to.

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Originally Posted by edcmat-l1

This is the kind of weird crap you get when you go changing things you shouldn't or don't need to.

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I know you are a big believer of leaving things stock, but you do realize that this is tuning and some things just need to be changed?

This why we are here. Did you look at the log?

What are your thoughts of why it would revert back to idle or pedal mode with the throttle pressed?

I don't think that should happen at all.

Its quite clear in the log that adaptive idle is pulling the spark down when it shouldn't even be in idle mode.

We know why its doing what its doing but the real question is, why is idle mode taking over with pedal imput?

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Originally Posted by Allen Vos

I know you are a big believer of leaving things stock, but you do realize that this is tuning and some things just need to be changed?

This why we are here. Did you look at the log?

What are your thoughts of why it would revert back to idle or pedal mode with the throttle pressed?

I don't think that should happen at all.

Its quite clear in the log that adaptive idle is pulling the spark down when it shouldn't even be in idle mode.

We know why its doing what its doing but the real question is, why is idle mode taking over with pedal imput?

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I am a firm believer in less is more, most of the time. A combo as basic as yours is a couple hour job for me tops. 2 or 3 dyno pulls, a road test, maybe a cold start the next morning, and we're done. No funky running problems.

The timing part of it looks just like spark smoothing. I have to believe you when you say you turned it off and it made no difference. That combined with what I know you've done over the past few weeks and I know it has to be something you've done.

If you brought the car to me to fix this one problem, we'd wipe it clean and start over with just the basics. Probably wouldn't touch half the tables you have, and we wouldn't have any funkiness.

It really is about the importance of fundamentals. You start with the basics/fundamentals. you get them solid, ironed out. Then you make small adjustments elsewhere WHEN REQUIRED not because someone said so on the innerwebz.

When you end up with problems like this you don't continue to add or change things to fix it, you UNDO what you've already done and either start over or work your way backward.

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Originally Posted by Allen Vos

I know you are a big believer of leaving things stock, but you do realize that this is tuning and some things just need to be changed?

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You do realize that there are many more things in an ECM than what you can see through HPT and that there are things you can see in HPT that may relate to unseen things? And that HPT may have unlocked things without having a real purpose as they figured out (sort of) what they did. All of this interrelationship between seen and unseen things is why you want to change as little as necessary to get it running correctly.

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Originally Posted by gtstorey

You do realize that there are many more things in an ECM than what you can see through HPT and that there are things you can see in HPT that may relate to unseen things? And that HPT may have unlocked things without having a real purpose as they figured out (sort of) what they did. All of this interrelationship between seen and unseen things is why you want to change as little as necessary to get it running correctly.

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Just because you can doesn't mean you should.

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Originally Posted by edcmat-l1

I am a firm believer in less is more, most of the time. A combo as basic as yours is a couple hour job for me tops. 2 or 3 dyno pulls, a road test, maybe a cold start the next morning, and we're done. No funky running problems.

The timing part of it looks just like spark smoothing. I have to believe you when you say you turned it off and it made no difference. That combined with what I know you've done over the past few weeks and I know it has to be something you've done.

If you brought the car to me to fix this one problem, we'd wipe it clean and start over with just the basics. Probably wouldn't touch half the tables you have, and we wouldn't have any funkiness.

It really is about the importance of fundamentals. You start with the basics/fundamentals. you get them solid, ironed out. Then you make small adjustments elsewhere WHEN REQUIRED not because someone said so on the innerwebz.

When you end up with problems like this you don't continue to add or change things to fix it, you UNDO what you've already done and either start over or work your way backward.

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I will post the tune shortly. I feel you are jumping to conclusions here Ed.

I'm not interested in someone telling me to put things back to stock as that's exactly what I have done, well as much as I can.

Lets actually try to figure this out rather than just keep saying "Put things back to stock", as that's not really helping anything.

Maybe you could explain in detail as to why the throttle source reverts back to idle mode despite pedal input? Shouldn't you know this having tuned as many cars as you say you have?

I don't believe its spark smoothing, partly because that did not work and also because you can clearly see adaptive spark pulling timing as its in idle mode.

It should not be in idle mode with the pedal pressed, but despite that, the idle mode is pulling spark to achieve idle rpm, so its doing what its supposed to.

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Originally Posted by Allen Vos

Maybe you could explain in detail as to why the throttle source reverts back to idle mode despite pedal input? Shouldn't you know this having tuned as many cars as you say you have?

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I know you enjoy taking shots at me. I don't know what exactly is causing it. I don't have these types of problems. Like I said earlier if it came in with that problem it gets flashed back to stock with a GM MDI2 and we start over. I'm not looking to fix someone else's screw ups. I do things my way and they work time after time after time.

You guys remind of Paul Sr and Paul Jr. from Orange County Choppers...lmao

I don't throw stuff or lose my cool.

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Originally Posted by sgod1100

You guys remind of Paul Sr and Paul Jr. from Orange County Choppers...lmao

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Hilarious LMAO
Attachment 144465

^^^ Got a nice big laugh outta that.

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Originally Posted by edcmat-l1

I know you enjoy taking shots at me. I don't know what exactly is causing it. I don't have these types of problems. Like I said earlier if it came in with that problem it gets flashed back to stock with a GM MDI2 and we start over. I'm not looking to fix someone else's screw ups. I do things my way and they work time after time after time.

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Its not that I enjoy taking shots at you, but you have a bad habit of coming on to peoples post including myself and just saying put it back to stock. Then talk about how good you are at tuning , then offer no insight to anyone's issue.


So you do realize that this is a public forum where people come for help? Then you come on here saying that you do things your way and don't have any problems? Then say your not here to fix anyone's screw ups?

Why are you even on here responding to posts then? Are you here to just hear yourself gloat?

This is part of tuning and learning and why we are all here. A lot of us learn from our mistakes here too, so this may very well be something that I did, but it might not be. Point is, I am here to figure this out. Bringing my car to you , where ever you are and starting over would not help me learn anything now, would it?

So being that you have tuned thousands of cars, and your on a public forum that's supposed to help people, here's your chance to prove yourself with your wealth of knowledge..

Here is my tune Attachment 144466.

I know you mentioned spark smoothing, but I don't believe that's the issue here. You can clearly see on the log its going into idle mode with pedal input
and that's why the idle is not stable. Again turning spark smoothing off did nothing for my issue

I have no complaints with how the car starts, runs and drives except for a couple small little hiccups that I am trying to fix, this being one of them.

Its not the end of the world but it would be nice to fix this. I should mention it does not do this while actually driving the car.

The only other thing I want to nail down

So there it is, you asked for the tune, the log is here as well.

Maybe you can offer some insight and a good explanation as to why this issue is here

Is there not settings to fine tune the idle /pedal mode?

Surely others have run into this?

FYI. I have put the torque tables and the throttle follower table back to stock as part of my troubleshooting and it had no effect on the issue.

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Originally Posted by Cringer

Hilarious LMAO
Attachment 144465

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Scary thing is, there's a lot of truth to that LMFAO!!!