G4+ Fury - Cold start and idle tuning

[mjb214]

I have been trying to get the idle to smooth out and have the cold start and warm up run smoother.  I have gone through several iterations of log and edits.

The car was dyno tuned and other than the idle drives fine.  

At startup sometimes there is surging in RPM enough to stall occasionally, at warmup there is sometimes surging of 100-150 RPM.

Are there any settings or things I should be looking at to smooth it out on warm up and hot idle?

Log link -  https://drive.google.com/file/d/1xkbDpnOuDXDYgQ3ZnvmQybZFQb3Vh9w2/view?usp=share_link

Tune link - https://drive.google.com/file/d/1BSN7T1yl8a1C-kcXck8bSj50MUgaew7B/view?usp=share_link

Car information

92 MR2 - 3.5L V6 - 2GRE-FE with a single BW Turbo

525cc Injectors

I have additional Logs and other tunes as well, this was my last attempt

 

Thanks you for help/advice

[Tim D]

I noticed that AP is around 0.8% at idle and AP/TP lockout is 0.5%, meaning that ignition idle control is never activating, you could try setting this to 1%.

Also, the Idle Ignition Table should have a value of 25 degrees at 0 error to match the ignition timing at idle.  It currently has 10 degrees.  You could try 0 degrees at -500 rpm error, 25 at 0 rpm error and 30 at +500 rpm error.

I think this will help...

[koracing]

I agree the ignition idle control lockout should be increased - I would increase both the lockouts for idle timing and idle control to 1.5% AP/TP lockout.  In addition you may also want to try the following things:

1. increase your control range on the idle control from 150rpm to 300-400rpm above target.

2. increasing the deadband on your accel enrichment to 2%TP as when you oscillating starts you're dumping in some fuel intermittently. 

3. Your integral on your e-throttle value you can try decreasing as the oscillation is often due to too agressive of an integral value.  Currently you have it set to .051 - pernaps try lowering to .03. 

4. Increase max idle ignition control rpm to 1600rpm

5. the idle ignition control can be quite a bit more aggressive - I usually make breakpoints at +/- 50 rpm and have 5-10 degrees offset from 0 target either way at that point and your values at +/- 300 at +/- 100.

6. idle base position as it's idling about on target with 3.6% cold and 2.6% warm but your e-throttle target plus current base position only add to 3.1% and 2.5% at those points respectively.  It's usually better to set the base position slightly above required (maybe e-throttle target to 1.2-1.5% in the lower rpm range at 0 AP Main).  To prevent stalling you can set the E-throttle target at 0 and 500 rpm even higher to artificially "pop" the throttle open in a stall situation.

[Adamw]

The main cause of the surge is the idle antistall gain is too high, drop this to 2.0.  This kicks in if your RPM drops 150RPM below target, so you are increasing the proportional effect by 800% when this happens with your current settings.

Something is a bit fishy with your throttle pedal, at the beginning of the log it is reading 0.6% at rest, at the end of the log it is sitting at 1.1% at rest, it should read 0% whenever it is at rest.  It may be something mechanical such as it is not positioned well so your foot rests on it too heavily or it could be some electrical issue - worn sensor or ground offset etc.   This is preventing idle control from even activating. 

So those two above are the most important things to fix first in my view.  I agree with most of the other suggestions given also but want to add a couple of further related comments:

• Def Increase RPM lockout in both idle speed control and idle ign and KO suggests.  
• I agree that the idle base position appears to be about 0.5% too low - but with G4+ to get a nice transition from idle to driving, you are meant to have the bulk of your idle position coming from the main e-throttle target table and only small values in the idle base position table (mostly just whatever extra is needed for warm up) - so I would change it up a bit - put 2.0% right across the whole top row of the e-throttle target table, then subtract 0.5% from all the current values in your idle base position table.
• I wouldnt adjust the E-throttle integral at this stage, you already have quite a high target error accumulator count in some areas so I wouldnt want to make it less responsive.  
• Whilst I agree the Idle ign could be more aggressive if needed, I think I would leave it as is for now, it isn't even activating at present due to your APS issue so just fixing that will make a big difference.  

 

Not related to your idle issue but a few other things I spotted:

• you are getting a lot of integral wind-up on your LH exhaust cam.  A couple of things causing this - It is reading about -1deg with the cam fully home sitting on the mechanical stop so the ecu is pulling out more and more DC trying to force it to zero.  Adjust the offset on DI1 so that the LH exhaust position reads 0 at idle.  Secondly, increase the VVT RPM lockout to about 1200 so its not active at idle when there is little oil pressure. 
• CLL is pulling 15% fuel out at idle and it is still about 5% richer than target when warm so something in the tune isn't right.  To me the values in the idle area of the charge temp table look too small for a V engine where the intake manifold probably runs quite a bit warmer than a typical inline engine.  This could potentially contribute to stalling or an undershoot when entering idle conditions excessively rich.
• Battery voltage is not very good in the log, about 12.7-13.0V at idle which isn't too unusual, but still only 13.1V max at 4000rpm.

 

[mjb214]

Thanks that really helped a lot, the idle is so much better.  Here is the updated tune/log from today with these changes made.  I charged the battery up before doing this, I had swapped to a higher output alternator but still seems to not charge enough.  I'll investigate that further another time.

I also did a recal of the eTB before starting it to see if that was not right.  It seems to hit 100% throttle at 75% pedal still so I'll recal the pedal next week as well to see if that was out of whack.  There should not be anything obstructing it on 0 or on 100.

Do you think it is still idling too rich?  

I changed the two cams that were not showing zero until they hit zero think it was LH exh and RH exh.

Any other advice would be great

Log - https://drive.google.com/file/d/1oQVV9WocHnutQURNrq05pg24bMh0EWZG/view?usp=share_link

Tune - https://drive.google.com/file/d/1kh229pdMl5rroluMpmOnGrCMuxRg-iI0/view?usp=share_link

 

Edit* There was a pretty solid backfire right near the end of the run ~42:40minutes.  I was reviewing the logs to see and it looks like it goes from 29 degrees timing to zero then back and then again it hits 5 BTDC ~43min.  So something is overriding the ignition table but I can't figure out what it is.  

Edited May 7, 2023 by mjb214
Added more context

[Adamw]

On 5/7/2023 at 7:58 AM, mjb214 said:

There was a pretty solid backfire right near the end of the run ~42:40minutes.  I was reviewing the logs to see and it looks like it goes from 29 degrees timing to zero then back and then again it hits 5 BTDC ~43min.  So something is overriding the ignition table but I can't figure out what it is. 

That is just idle ignition kicking in.  The speed lockout isn't working as you dont have a non driven wheel speed assigned.  You can assign your RR wheel as both the driven and non-driven wheel to solve that.  I think the backfire is actually at about 42:47, if you look at dwell you will see a spike down to 1.4ms.  Im not quite sure of the reason for that - it is aligned with idle ign activating so possibly something related to the sudden change in ign advance from 30deg to 0deg.

 

On 5/7/2023 at 7:58 AM, mjb214 said:

It seems to hit 100% throttle at 75% pedal still so I'll recal the pedal next week as well to see if that was out of whack.  There should not be anything obstructing it on 0 or on 100.

Not sure what you are saying here, it appears to be following the target ok to me. 

 

On 5/7/2023 at 7:58 AM, mjb214 said:

Do you think it is still idling too rich?  

Yeah, its still pulling 15% out whenever it is idling.  

[mjb214]

Could it be the closed loop ftrim?  it has a limit of 15% which aligns with what you are seeing.  Should I pull fuel out of the fuel table to make it fall within the 15% or do I raise this.  It seems to me that pulling fuel out at idle on the fuel table would be better and try to stay in the middle of the lambda targets.

 

[koracing]

Yes if it's pulling 15% and rich, you ideally want your base fuel table to be tuned such that your trim is close to 0% when fully warmed up.  In this case it would mean pulling 10-15% out where the closed loop is pulling 15% and then re-evaluate.