g4+ Ford V8 Stalling Issue

[Mcfly94]

Hi guys

I've got a bit of a cold running issue where my car stalls when cold when coming to a stop and returning to idle, sometimes its the moment just before I stop, sometimes its still while I'm rolling at 5-10kmh.

I'm not sure if its got to do with the lock out settings of the Idle Ignition Control or Idle Air Control.

The other issue is; when it stalls, it starts and runs like an absolute pig like the plugs are fouled up until it warms up and clears the cylinders out.

Its a 400 cube turbo Windsor, genuine Ford 2-wire IAC unit. 200hz Operation

It has been tuned by too workshops but looking to dial in these last bits as they can be time consuming.

The first shop that tuned it had the cold running the best, this was with the Idle Air TPS lockout at 0.8% and the Idle Ignition Speed Lockout at 0kmh (I didn't have wheel speed at the time) but it definitely ran better cold.

Can someone confirm some settings for me?

I'm looking to change the Idle Air TPS Lockout back to 0.8% and also lowering the speed lockouts on Idle Ignition and Idle Air from their current 5kmh back down to 2kmh.

I'm assuming the post start enrichment is a little heavy and causing it to overfuel?

Any who, here is the current tune and log of it stalling

https://drive.google.com/file/d/19X8efKxI5fbnpwRk_FMG5eWELL-FWXlU/view?usp=sharing

https://drive.google.com/file/d/11aXYCPsBaDbo2kGoorcH1QrFgGO5v2s8/view?usp=sharing

[Adamw]

Im a little suspicious the stall issue is mostly fuel related.  It goes quite lean just before the stall or near stalls.  I would make these changes first then do another log:

1. Confirm TPS is working correctly - The log shows the car accelerating to 50kmh at 0% throttle and gets to 80kmh at 2% which possibly seems optimistic.   
2. Update firmware, there were a couple of small ISC improvements in 5.6.8.
3. Change Idle Ign speed lockout to 20kmh and TP lockout to 0.5%.  
4. In idle speed control change the speed lockout to 10kmh, RPM lockout to 500 and TP lockout to 0.5%.
5. Change the highlighted cells below in both AFR target tables to 0.95.  

[Mcfly94]

Hi Adam,

I’ll make the changes and report a log back; your correct the TPS was not 100%, I have since calibrated it.

Curious on point #5; would it be possible the fuel table isn’t 100% and the closed loop fuel is not quick enough to correct the lean spot ? I would have thought it would handle lambda of 1.00 at idle.

[Adamw]

25 minutes ago, Mcfly94 said:

Curious on point #5; would it be possible the fuel table isn’t 100% and the closed loop fuel is not quick enough to correct the lean spot ? I would have thought it would handle lambda of 1.00 at idle.

CLL is locked out until 65°C so it is not even working during the first stall.  Lambda target of 1.00 is fine if you have little overlap, injectors with good atomisation and good predictable short pulse width behavior.  Im not sure if you do or not, but a test at 0.95 will help confirm that.  

[Mcfly94]

I will give it a try for sure.

I know once warm it handles a target of 1.00 easily if not a little leaner.

Either way it will tell us if it wants more fuel at this point.

[Mcfly94]

Hi Adam, made the changes

No improvement to stalling issue but transition between the idle tables when hot seems smoother.

Log

https://drive.google.com/file/d/1xA-l-x0pihAf_vpo584zE_xbYJFmwNbs/view?usp=sharing

Updated Tune

https://drive.google.com/file/d/1pd6fwuEEuPmHvXkuHNIHc8j_meDCyVuz/view?usp=sharing

 

[Adamw]

Before the first stall the RPM was sitting on target with the idle valve down at 56%, but it was at 80% in hold mode during the first 2 stalls and the next few near stalls after, so assuming the valve actually works it should have had more air than it needs.  

I think possibly the problem may be a conflict between the ignition tables and the idle ign table.  You have 30-37deg advance around the idle area in the main ignition tables, but only 15deg in the idle ign table, so when you are slowing down and reach the idle ignition lockouts, you suddenly get 20degs of advance pulled out.  I would usually do both the main ign table and idle ign quite a bit different than this.  You really want to be relatively low advance at normal idle so you have more advance in reserve to quickly increase torque when needed by adding more advance. 

I have made some changes and attached below.  I have changed the ign table axes and the advance values around the idle area to give a better transition in and out of idle.  I have change the idle ign values too.  It may need the throttle screw opened a bit more to achieve acceptable idle speed now with less advance, but give it a try.

 

 

 

 

LTD Tune Ign changes.pclr

[Mcfly94]

Thanks Adam, I agree the actually feel is the engine cant handle the rapid change of ignition timing at colder temps, it was an aggressive transition and ive never liked how it did it but I wasn't sure what I needed to do to fix it.

Ill give this a go and report back; curious is it worth setting the AFR table back to 1.00? Because I don't think that made a difference.

[Mcfly94]

Hi Adam, so I tried that tune and to be honest it was the worst it has been.

So I went back to basics when it was its best, had two different tuners tune it so far.

They differences that they both left was Idle Ignition Speed Lockout at 5kph, Idle Air Speed Lockout 2kph, Idle Air RPM Lockout 800rpm, Idle Air TPS Lockout 1.5%, Idle Ignition TPS Lockout 1.5% and then Idle Air Min Clamp at 5%.

I thought real basic; it either wants more air or more fuel to run, so I dialled in some more warm up enrichment, tested last night and was improved but not 100%, so I dialled in a touch more no more stalling, no more rpm dip what so ever, I had a log but the app closed on my screen saver and didn't get a chance to save the log. This brings me to a question, I'm running multi fuel, does this mean I should take advantage of the multi fuel warm up enrichment? I'm assuming E85 takes more warm up enrichment? If that's the case Ill bring up my ethanol content, confirm my warm up enrichment values still hold, then activate the dual tables; get ethanol content right down and then pull warm up enrichment until 98 fuel is not over fuelling.

I'm no tuner by any means but slowing getting an understanding of what the engine wants, and your changes to my idle ignition table clicked an idea that my idle table was not aggressive in its attempts to correct idle error, in my application when cold commanding 15* at idle and then experiencing an idle error of +400rpm has never been enough to quickly raise the idle to prevent a stall, so in the +400rpm column from -20ECT to 50ECT I bumped 20* up to 25*, the other change i made was on the polar opposite for -400RPM error while warm (40ECT to 80ECT) up a little more advance so its not pulling to much if it ever needs to; in my application any form of low ignition timing seems to have a huge impact on heat soak and a result of a climbing ECT, I noticed this really bad with your ignition idle changes where it was commanding 0* with a -400rpm error, a couple times it hit 0* and the temps just started creeping; of course there's number of factors that are at play but this is what works for me.

Can't thankyou enough for assistance in a way it helped me to understand and see better the impacts of certain changes and how to read the engine in a log.

I have attached the current tune as is, I plan to test a few more cold drives to confirm my tune but for now the issue seems fixed.

https://drive.google.com/file/d/1LBcIKHnVhm7ozy6KdMwasi7miUwjhLOy/view?usp=sharing

Also I'm not sure why the idle ignition tables where setup the way they were but it works and the engine feels nice with them set that way.

Here's a photo of the engine bay for anyone interested what my Thunder is controlling.

$0

[Adamw]

Its still not going to work well dropping from 38deg at 2000rpm in your main table to 13deg as soon as idle ign activates at 2000.  You need those to match each other better.  

Im not too sure how less advance increases ECT.  When you retard timing your combustion is later so have more heat going out of the exhaust, but less going into the water jacket.  Exhaust manifolds will usually get a bit hotter, but EGT is usually low at idle anyway so is of little consequence.   

[Mcfly94]

2 hours ago, Adamw said:

Its still not going to work well dropping from 38deg at 2000rpm in your main table to 13deg as soon as idle ign activates at 2000.  You need those to match each other better.  

Im not too sure how less advance increases ECT.  When you retard timing your combustion is later so have more heat going out of the exhaust, but less going into the water jacket.  Exhaust manifolds will usually get a bit hotter, but EGT is usually low at idle anyway so is of little consequence.   

The other thing I can think of is maybe more idle timing because it felt really doughy with the timing pulled out at the 1200/1500rpm mark. This thing cruises at around 1500/1600rpm at 50/60kph so the timing is nice.

Yes it’s a drastic change but with the idle lock speed outs real low; when I’m coming to a stop it only changes just before I stop. 

The change in timing is more noticeable reversing up the driveway with no throttle engagement, but that dosent bother me.

Looking at some logs when coming to a stop more often than not it’s dropping from 25* back to the 15*.

It was previously worse in transition from when it was tuned; warm idle was 10* @800rpm but I bumped that to 15* at 850rpm and idles a lot nicer. I’ve been told it should handle 18/20* with ease as the factory AU 5.0 is 18* warm idle at 775rpm.

I would prefer to bump the idle ignition table to smooth the transition. But I’ll keep tweaking with it.

I could have worded it better; but for some reason EGTs have a big impact on under bonnet temps and just cooks everything. 

 

[Mcfly94]

Still trying to sort this out, I think its slowly getting there.

Ended up smoothing the transition from idle ignition to main however I feel like the issue is still fuel related so not sure which is the best way to tackle it, could it want more idle rpm when cold? IAC opening to quick when returning to idle?

This is where the current tune is at now. 

https://drive.google.com/file/d/1pCAdH2EG8o1ZiBUhswpm5YQdLxJesxWa/view?usp=sharing

[Adamw]

Got a log?

What is the behavior you are trying to improve?

[Mcfly94]

Hi Adam, same stalling issue and undershooting target idle when coming to a stop when cold (ECT < 50c).

I did try get a log but PcLink crashed whiled recording; been doing that a lot lately. Can I log without the PC connected? If not I might setup my AEM data logging and record from that.

 

I just don't understand why it is fine when warm, but when cold doesn't want to hold idle until up to around 50ect.

Are my Bosch 'modified' 1250cc injectors exacerbating a wall wetting affect? (I've seen a spray pattern video of them and it's akin to water pistols) I'm actually going to be replacing them with a genuine unmodified Bosch injector 1650cc flow matched set to get better fuel atomisation extremely soon!. 
 

Would more warm up enrichment help or make the issue worse by having higher pulse widths just shooting fuel on the back of the valve? 

 

 

[Adamw]

Yes you can do an ecu log, make sure you add all the relevant channels.  But PC Link shouldnt crash often, something is wrong if thats happening.  What error do you get when it crashes?  

Really need to see a log to see what the cause is, modified injectors may certainly be some of the issue.  But to me it still looks like a timing issue.  Your idle ignition table activates at 2000RPM, when that happens your timing drops from 40deg in the main table to 10deg in the idle table.  That is a fairly drastic reduction of torque when you have cold oil etc.  

[Mcfly94]

No error Adam it just closes the program and that's it.

 

I thought the new tune I uploaded was a bit smoother, it seems smoother, I just want to be able to cruise at 50/60kmhs with around 40* of timing in it. So I don't want to sacrifice that.

Could I change the idle ignition activation to say 1200rpm? Would that help?

[Mcfly94]

Some updates and further feedback on current issues.

1. RE: logging, turns out I think PCLink was 'crashing' as I called it, due to power saving features in the laptop; had the missus take a log to ensure the screen saver and battery saver didn't activate and successfully got a log. So not concerned about this anymore.

2. I adjusted the Idle Ignition Control RPM lockout from 2000rpm to 1300rpm; in the log can see the IAC shoots the Engine Speed over the the lockout and the engine is idling around 32* when first started; while running car I raised the lockout to 1700rpm and it stalled; it was good because it replicated the issue of stalling while coming to a stop and I do believe the stalling issue is now 100% timing related; specifically the lack of smooth transitioning.

Now, because I like the high timing values at low cruise and slow speed, is there anyway I can employ a timer and 4D ignition so that when coming to a stop we can create a smooth decay of ignition timing once the conditions of idle ignition are met; I'm thinking when the conditions are met if I could somehow decay the 40* timing down to 15* over like 2 seconds somehow? like once its activated the timing drops 5* ever 0.5s too smoothen it out? Its just an idea, and not sure it can actually be done but keen to hear others thoughts.

The car cruises at 50kmh at roughly 1500rpm in 3rd and I wouldn't want any less timing than it currently has at this speed.

3. I recently changed my final drive ratio from to 3.91 down to 3.23 and while driving at cruise; 90kmh it takes very little throttle and sometimes to reduce speed I need to completely let off the throttle and the overrun fuel cut kicks in and pulls 10* timing and results in bucking, as a band aid fix I raised the deactivation rpm from 2000 to 2600rpm and it fixed the issue however I feel like a better adjustment would be the activation delay from 0.5s to 1.5s? What are everyone else's thoughts?

Today's Log. 

https://drive.google.com/file/d/1lUqgS-XehZcd3TEkrSl9oKrbdQ10S0OY/view?usp=sharing

[Adamw]

If idle and cruise is the same RPM, what can we use to distinguish that you want it to idle?  Is MAP or TP different when at cruise compared to idle?  

 

On 11/7/2021 at 4:59 PM, Mcfly94 said:

The car cruises at 50kmh at roughly 1500rpm in 3rd and I wouldn't want any less timing than it currently has at this speed.

You could possibly put more normal advance values in your main ign table under say 2000RPM so transition to idle is better, then add a 4D ign table with RPM Vs Speed to add the extra cruising advance when the car is moving at say 1200-2000RPM.  

 

On 11/7/2021 at 4:59 PM, Mcfly94 said:

I recently changed my final drive ratio from to 3.91 down to 3.23 and while driving at cruise; 90kmh it takes very little throttle and sometimes to reduce speed I need to completely let off the throttle and the overrun fuel cut kicks in and pulls 10* timing and results in bucking, as a band aid fix I raised the deactivation rpm from 2000 to 2600rpm and it fixed the issue however I feel like a better adjustment would be the activation delay from 0.5s to 1.5s? What are everyone else's thoughts?

Not so much the delay, but the torque reduction/introduction time will have more effect on how abrupt it is.  I generally find about 1.5 sec for the torque reduction/introduction and 15-25deg retard gives a smooth transition in and out of ORFC.  May need even longer time in this case.  

[Mcfly94]

Hi Adam, moved my torque reduction delay to 1.5s and very smooth transition and don't even notice it while driving now; thanks for that.