13 Coyote badly hunting idle

[JonJ]

Not quite sure how to go about fixing this, it's a turbo car that sounds like a blower car. Starts up fine and idles smooth until you tap the throttle when it goes into torque based idle and then hunts back and forth between 20-30 degrees. The stft swings equally high plus and minus when it does this. I did notice that it is showing a torque of -15 ft lbs when the issue occurs. I have looked and searched on the forum quite a bit and there is tons of info, so much in fact that I really am not sure the easiest way forward.

I've attached a log of this occurring. Appreciate any input.

[Dan Stewart]

Pretty common issue, but rarely anything anyone has been able to say "it is x".

First, I would recommend getting your torque tables dead on at idle.

If you've used the Cookbook to build the tune, I've noticed that the FI cars all end up hunting idle. (I might dig further into that to see if I can't find the root cause). I have a feeling that it is the cam settings recommended that screw up idle.

[mstang_man]

check your drivers demand, if that to high it will cause hunting idle

[blackbolt22]

I believe tuning Driver Demand will be a waste of time and will cause more issues because it's already idling fine in Driver Demand mode. Go with the Torque tables since Target N is where the problem exists. Once you start going in the right direction it may hunt a little but then switch back to Driver Demand mode and fully stabilize like before you tapped the throttle. This is all assuming you haven't messed with Idle->General settings.

Oh and please post back your results.... this is a common issue...

[Thatwhite5.0]

Post your file. Just like Dan said, it's hard to pin point or help solve a problem when theres many possibilities.

You engine torque drops to -15, your air load drops lower than an NA car and your driver demand request increases to keep the car alive, torque control.
Post your tune.

[veeefour]

Your EVC goes to 10' of advance - that is why it idles like that. You want to advance your IVO to +10-30' to help with idle not EVC.

Fix your VCT.

[Dan Stewart]

Your EVC goes to 10' of advance - that is why it idles like that. You want to advance your IVO to +10-30' to help with idle not EVC.

Fix your VCT.

I think we might be on to something here. Now if OP ever returns and says, "yeah, I used the cam settings in the book to build boost". It does do that and darn good too, but screws up idle. I'll look tonight.

[veeefour]

Sure but don't do it for idle - everything is in your Optimal Stability table

[JonJ]

Last few days I have tried all sorts of stuff and nothing had any effect. On a whim today I took the stock Boss file as pulled, added injector data and e85 stoich only and it settled down into a nice idle. Seemed snappier on a free rev, too. My turbo kit charge pipe does have a little different diameter than stock so the stft was around 27.
So this has all the vct mapped points enabled. I did not change the torque or inverse at all. It's a twin turbo car so it should still operate as stock in the lower throttle ranges right?
I do need to fine tune the top of my maf transfer, it gets rather coarse, and might need to go to 20.
Anyway, here is the file that gets tried out tomorrow. Let me know what needs work.. got my fingers crossed.
Thanks all!

[veeefour]

Oh I missed that it's a TT setup. I have my idle tuned like a butter on low mount twin turbo.

Turbo requires tuning idle as it's a choke for exhaust and produces some parasitic losses. On S550 you want to increase Idle Torque.
On S197 you need to work on your Dashpot which is very difficult. It's one place where S550 is actually easier.

But first fix your MAF transfer because it's just terrible. Switch those to disabled and turn your LTFT off and work with your STFT only.
Clipboard01.jpg

Your optimal stability up to 3000 rpm calls for 0 OP point which is also 0 MP. Try setting MP0 IVO to +20 and see if this makes any positive change.

Clipboard02.jpg

Plus in your first log your car idles at OPTIMUM POWER MP.

[Thatwhite5.0]

The problem is in your torque/inverse tables..
Your torque table scaling needs to be higher than 1.1 load.
Just focusing on idle for now.
I just took a look at tq/inverse 0 where yor problems occurs. The inverse axis is scaled incorrectly for the values you have in torque 0. Just to test, because they're pretty low. In row .2 load. Add 15 ft lbs to that row. .3, .4, .5 load add 28 ft lbs to those row.. there are more parts that need work. This is just idle. I can put something together soon.

[veeefour]

A lot of things wrong in this tune. This can't work right.

[Thatwhite5.0]

Yes. I'm not with my laptop. But I remember both tq and inverse need remodeled. Vct section has a lot of changes too.
Also change your optimal stability mapped point. You have
0
7
0
0

Change the 7 to use 10.

[Thatwhite5.0]

I was putting something together that would give you a good start. Do you have a return fuel system with your setup?

Your optimal stability up to 3000 rpm calls for 0 OP point which is also 0 MP. Try setting MP0 IVO to +20 and see if this makes any positive change.

Do you mean -20? It is a first gen. There's no retarding the IVO passed 0.

[JonJ]

Yes it is a return system.. the tq and inverse in the file i posted are oem, not sure how the inverse could be out? I'll take a look

I was putting something together that would give you a good start. Do you have a return fuel system with your setup?



Do you mean -20? It is a first gen. There's no retarding the IVO passed 0.

[JonJ]

I went back to the stock strategy pull, made 3 changes: injector data, stoich point, mass airflow transfer, and wrote it back in the car, here is the result. Obviously I can't go hit boost as it sits but it idles and revs a lot better. So this is the exact same torque and inverse, driver demand, and so on as the file I posted above: why such a drastic difference? I see in the log this time shows near zero torque at idle and almost no error. Why? I just want the damn thing drivable besides WOT again lol

[veeefour]

I was putting something together that would give you a good start. Do you have a return fuel system with your setup?



Do you mean -20? It is a first gen. There's no retarding the IVO passed 0.

In reality retarding the IVO means +, retarding the EVC means - one is already late and other is already early.

[Dan Stewart]

I went back to the stock strategy pull, made 3 changes: injector data, stoich point, mass airflow transfer, and wrote it back in the car, here is the result. Obviously I can't go hit boost as it sits but it idles and revs a lot better. So this is the exact same torque and inverse, driver demand, and so on as the file I posted above: why such a drastic difference? I see in the log this time shows near zero torque at idle and almost no error. Why? I just want the damn thing drivable besides WOT again lol

I've used the stock tables with just the injector and fuel data changed for return and had the same results where it idles fine before touching the VCT tables.

Seeing a pattern here.

[JonJ]

Oh I missed that it's a TT setup. I have my idle tuned like a butter on low mount twin turbo.

Turbo requires tuning idle as it's a choke for exhaust and produces some parasitic losses. On S550 you want to increase Idle Torque.
On S197 you need to work on your Dashpot which is very difficult. It's one place where S550 is actually easier.

But first fix your MAF transfer because it's just terrible. Switch those to disabled and turn your LTFT off and work with your STFT only.
Clipboard01.jpg

Your optimal stability up to 3000 rpm calls for 0 OP point which is also 0 MP. Try setting MP0 IVO to +20 and see if this makes any positive change.

Clipboard02.jpg

Plus in your first log your car idles at OPTIMUM POWER MP.

It does, but the cam angle stays constant between when it idles smooth and when it surges, so I can't see how the cam angle could be causing this.

[JonJ]

The problem is in your torque/inverse tables..
Your torque table scaling needs to be higher than 1.1 load.
Just focusing on idle for now.
I just took a look at tq/inverse 0 where yor problems occurs. The inverse axis is scaled incorrectly for the values you have in torque 0. Just to test, because they're pretty low. In row .2 load. Add 15 ft lbs to that row. .3, .4, .5 load add 28 ft lbs to those row.. there are more parts that need work. This is just idle. I can put something together soon.

Any further insight? I tried the Roush torque and inverse tables which seem to be quite popular; no change was seen. Here is another short log, still locked in OP mode for now, trying to dial in the torque tables using ETC error. Not sure if I'm getting anywhere just yet.