Cammed VE L98 after start enrichment issue

[The Alchemist]

Hi people, just trying to sort a few issues before the car's picked up by the customer.
Issue: only when left outside overnight (temps 5 to 8 deg overnight) engine starts perfectly, idles perfectly for 4 secs then putters out and stalls. I know this is an afterstart issue with fuel pooling out etc etc . Second start is perfect with normal idle and no hint of a stall.
Keep the car inside overnight and it doesn't do it at all. Frustrating!

In the E38 calibrations there doesn't seem to be afterstart enrichments settings like in the LS1 Calcs.....Is this correct or is it called something else, am I missing something ?
If they are in the calc but not available in the tuning software should this be something to be added as a new feature???? > Blacky GPMX ?

I've been tweaking the IVT table in the temp range which is helping a bit but it makes the AFR's quite rich once the engine has passed the stall time zone (5secs) until the IVE temps come up... Is this all I can do with the current software?

THANKS,

Mike

[GMPX]

Mike, just as an experiment disable {B1219} Low Volatility Fuel Detect. This has been known to cause major fuelling issues on cammed engines. It's only something that came in on a 2010 E38's, or, is this the same car we've already done this for?

[The Alchemist]

13199

13200yeah mate same car...just came back with a few other little things to sort before the new owner picks it up. I threw in 5% more on the IVT open loop table and that sorted it...except it does this other strange thing too that I've noticed and only on the first cold start of the day.....
heres a screen shot of that event and a log of it plus my drive to work testing 100km/hr gear change points. Have a look. The engine is tuned mafless which may be part of the problem.

The injection ms just after startup drops to almost nothing for just an instant because the APCYL_dma drops out 0.04g/s just for an instant. The engine then falls into a stall only to just pick up at the last second when injection ms and G/s starts to read again.
Any suggestions people? Anyone seen this before?

Mike

[The Alchemist]

Also while I've "got you" Ross can you have a look at this please...its really important with cammed cars and the masses will love you for it if you can do this???

quote from idle sticky thread....

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. " end quote

Mike

[GMPX]

Also while I've "got you" Ross can you have a look at this please
My attention span is about as long as an injector pulse.

For the gltich you see on the airflow, open up B8801 (Normal VE Coefficients), go all the way to the right and check if the [MAP_SQ] column has anything but zero's in it.
If it does, go back to the VE table, select the entire thing and then add 1 (just one so all the cells get changed). Now regen the coefficients and save/flash that tune in.
Let us know how that goes.

[The Alchemist]

It all had 0's in the column. Have added the "1" though and will try again tomorrow morning..

Tried it this morning with the "1" added to the VVE table and its exactly the same

[Naf]

I had a similar problem. What are your Max idle 1 and 2 set at?

A tune would be helpful

[The Alchemist]

well Naf I could max them out...you get to a point u see where increasing them in the calibration does not increase the actual past a certain % opening. What I have found is that different operating systems have different maximum actuals regardless of what you put in idle 1 & idle 2. Clearly there is a setting not available yet that allows a "maximum % opening of the throttle blade at idle" If this was available it would end all the problems with big cams and poor idles and drilling TB's etc to achieve enough airflow.

[Naf]

Whats your AFR durin startup? May we have a log...?

Like i said, the first startup i use to have had a similar effect, but it use to drop to 200-300rpm then surge up. Then idle decently and run like there wasnt a problem.

Try increasin the blend of spark from start to idle, B5135. If you increase it it may help you keep the engine runnin after initial start up.

[swingtan]

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. " end quote

Mike

Hi Mike,
I have {B1650} set at 3800 and {B1701] set at 6800

With these settings I can easily get 16% throttle and 20gm/S airflow. I've never had a P0606 and I've done some pretty nasty stuff.......

Reducing these settings not only allows for greater throttle position on idle, but also increases the effects of the proportional / integral step sizes. IE, these settings give more correction when the throttle area settings are reduced.

As for why the settings are different between models, maybe GM are doing exactly the same thing and "tweaking" the area values to help control idle.

Simon.

[Naf]

Have you increase B1602 as well?

You may increase it till it literally increases the rpm past your set RPM.

I found that if i start at .4 at -40 and work down to .325 at 92 and 104 my idle is relatively smooth.

At one point i had it start at .6 till the same .325 and it increased my rpm by 200 durin cold idles. I lowered it till my desired rpm was meet through the warmup cycle...