E38 idle tuning

[ringram]

I did get an ETC code and have to adjust airflow vs tps or whatever table.
But I have many more cubes behind it. I definitely need B1650 otherwise things are bad with cold starts etc.

[The Alchemist]

cold start 3.efi

Hi guys , another cold start idle issue to address so I thought this would be the best place to post.
VE Holden L77 engine with AFM delete kit and a big LS3 cam 235+ duration 600 thou lift, full exhuast, FAST manifold etc etc. You know, one of those "just a tunes"

Problem: Cold start is fine (learnt a whole lot since my last posts on this topic !!! ) but the commanded AFR is 9.98:1 and commanded lambda 0.688 so the car runs very rich pulse width 6ms!! with horrible surging as a result. I'm running similar IVT open loop tables to other cammed VE's and have never seen this problem before.
At exactly 40seconds after 1st startup (done 4 cold starts logged and measured) the commanded AFR & Lambda suddenly jumps vertically to 12.8:1 & 0.881 respectively and the pulse width drops to 3.8ms and the car idles beautifully. At the change point the IVT is at 50deg and the ECT is at 35deg. I even dropped the IVT open loop B0146 table flat from 56deg backwards and it made no difference to commanded AFR/Lambda. It only occurs from dead cold, if you stop the engine just after the switch point and restart the commanded appears normal around 12.8:1. No other problems during warm up and the car runs great etc etc. One of the first things I did was check LTFT's which are turned off but these read "0" as I had done a fuel reset as a matter or course.
O/S 12647991 Calib 12647990 2012 VE Holden.
Any suggestions fellas? I'm really stuck here.....

[hymey]

Hi bud, I did a L77 lifter swap 236-242 cam 11.8:1 a few months back. I must admit I have never had this pulsewidth issue. I also am unsure how you setup the open loop tables are B0141-144 all the same? try setting them all to 1.00s if u havent done it and B0147 to 1.00 and just use B0146 to change commanded fueling if you have already done this just to test, use completely stock open loop tables. See how it responds then try using all 1.00s in B0146. To be honest this car has completely stock open loop tables and dynamics and cold start drivability is awesome, not to smelly at idle cold start either which is typical of more overlap and metal cats. As far as idle tuning I still do the same things and it still works I have tried other methods and had some good results but have all charts written up now and always get them close within a couple of flashes. Try and finess the VVE as much as you can i find if it is autocorrectly to many cells after you have made changes close the tune and reopen and then make changes try it and see what happens. I also built tuned a 408 and runs a 250s cam it runs like a baby dead cold certainly makes life a lot easier to drivability tune with a 4.00 inch crank in there.

[Chuck CoW]

cold start 3.efi

Hi guys , another cold start idle issue to address so I thought this would be the best place to post.
VE Holden L77 engine with AFM delete kit and a big LS3 cam 235+ duration 600 thou lift, full exhuast, FAST manifold etc etc. You know, one of those "just a tunes"

Problem: Cold start is fine (learnt a whole lot since my last posts on this topic !!! ) but the commanded AFR is 9.98:1 and commanded lambda 0.688 so the car runs very rich pulse width 6ms!! with horrible surging as a result. I'm running similar IVT open loop tables to other cammed VE's and have never seen this problem before.
At exactly 40seconds after 1st startup (done 4 cold starts logged and measured) the commanded AFR & Lambda suddenly jumps vertically to 12.8:1 & 0.881 respectively and the pulse width drops to 3.8ms and the car idles beautifully. At the change point the IVT is at 50deg and the ECT is at 35deg. I even dropped the IVT open loop B0146 table flat from 56deg backwards and it made no difference to commanded AFR/Lambda. It only occurs from dead cold, if you stop the engine just after the switch point and restart the commanded appears normal around 12.8:1. No other problems during warm up and the car runs great etc etc. One of the first things I did was check LTFT's which are turned off but these read "0" as I had done a fuel reset as a matter or course.
O/S 12647991 Calib 12647990 2012 VE Holden.
Any suggestions fellas? I'm really stuck here.....

Hmmmm.... It's interesting what you say about the 40 seconds.... Has anyone else seen the 40 seconds thing? I've always seen that

there IS some timer and there IS a noticeable change when that timer expires.... Can't quite put my finger on it, but I would love to

hear from anyone who has seen this or knows more about it.....

Chuck CoW

[The Alchemist]

yup thats exactly how I do it Hymey Its like theres and after start enrichment table that expires after 40 secs that we don't have access to????? will try setting B0146 all to "1" and see how she goes today. thanks for your support.

[The Alchemist]

DRIVE TO WORK.efi

THIS IS THE COLD START , AND A DRIVE TO WORK, with b0146 set all to "1" as well as the b0147 b0148.
as you can see something is commanding 10.5:1 or 0.716 lambda for 40 sec after starting. Screen shot zoomed in on AFR and lambda. You can also see that for 15 sec after startup 3 small blips on the commanded AFR/Lambda.
ANy ideas about this?
Perhaps Ross may shed some light here for us > Ross?

cheers,
Mike

[The Alchemist]

EFILIVE had found the fix....an update will be posted shortly

[kangsta]

was it a newly uncovered table?

[The Alchemist]

yup it was, but its not "new" , just one that hasn't been used by GM calibrators in older calibrations. A explanation on said table/feature will follow in an update shortly as this table will affect cammed engines cold starts. Standard engines it has no effect so not to worry with those.....

[The Alchemist]

Next problem....."Fixing" a poor idle issue on a big cammed VE for a customer.Os: 12612381 Calib: 12612380
An early Model VE Holden.
The main culprit is that the biggest ECT TP it will command is 12.7% and thats it even with B1652 at 6 which maxes it out. This is in open loop idle tuning with Min idle airflow maxed out to 63g/s and intergral/proportional set to "0"
The VE 2012 model I've just finished tuning allows 18.8% with B1652 set to only "3" making cold starts a dream cos you CAN open the throttle further to get the airflow you need.
Surely there is a setting that can be made available that sets maximum throttle blade angle in idle mode. In earily calibrations this may be set much lower. I've followed exactly the same approach as I always have in setting up the idle.
My other question is: why does B1650 Max etc area change between models/years with the same throttle body attached to the engine??? I have tried changing this before to tweak max idle ECT TP but often get a limp mode fault P0606 ECU dead. Ringram you say you change B1650 with cammed cars. Could you please let us know how much you change it and what you have achieved using this approach. Changing this value though is surely a bandaid approach. I still think there is a setting for max allowed blade angle at idle because of the different max ECT TP at idle I'm seeing between different years of VE Holdens. Thanks.