now that I've got the idle sorted and the VVT up to 100kpa sorted I'm getting a 2 bar MAP sensor for tomorrow as the factory VE MAP sensor maxs out at 120kpa....not 1.5bar like I've read in the forum sites.
Only one way to find these things out is to try it for yourself aye?
I guess the fact that its climbing out of the dyno in 4th at 2000rpm speaks volumes of what to expect tomorrow!
"Just a tune > yeah right !!!! "
Ah, that might explain some weirdness I have been seeing! It appeared that nothing I did changed anything. Ill pull the fuse!Originally Posted by hymey
2008 Z06 C6 Corvette
Ok, pulled the fuse still no good. This illustrates the issue exactly.
You can see just at the selection line etcpos is at 20% 2 frames later its at 12% and spark hasnt changed. This is crank fire nicely, dropping to hard into normal spark.
Now g/sec is around the low 20g/sec range and drop to around 8g/sec when the throttle closes. My min idle air is 10.2g/sec.
I pulled the ECU fuse. But this is the issue. No matter whats in min idle air or the correction table after firing it drops too low. Ive messed with just about every table under the sun.
I know you guys want me to drill the throttle and Im at the point of doing that now to take care of the issue, because when its cold it dies. You have to hold the throttle down a while till it gets to around 40*C ECT before it will sort itself out. Eventually at temp we are still around 10g/sec and all is now well.
I need to ramp ETCTP down from the fireup 20% to the hot idle more gradually over time, but it wont do it no matter what. (Ok maybe if I drill the mother)
My correction table at the point above says 1.2x and even at 1.5x when colder so I should have around 13g/sec but I dont. I have used even higher numbers in the ect airflow correction table to no avail.
Any ideas accepted gratefully
2008 Z06 C6 Corvette
Post or PM me your tune file so i can take a look. I'll send it back with something for you to try.
OK, try this to help iron out the Idle learning....
Repeating my self a bit, all engines have some amount of inherent "lope". I find that trying to correct that lope can lead to increased instability and idle problems. So I look for what I think is the "natural lope" and don't ( or only marginally ) correct for that. So....
- {B1845}: Idle Proportional Step Size - This is like the "long term" idle adjustments ( though it comes into play fairly quickly ). For "Normal Idle" I have all cells from +64 and -64 set to "0" ( that includes the +64 and -54 cells ). This basically disables long term idle corrections when the idle is close to correct, leaving you only the Intergral, or instant idle corrections ( which are much smaller steps ).
- {B1652}: Max Idle Area 2 - Or stationary idle, set at a fairly high value. My belief is that this value is related to the logarithmic throttle control function like the PE tables. So 2% here should relate to about 18% max throttle when logged with ETCTP. 2.5% herer should see around 21% to 22% at the throttle but you may need 3% to get to a real 26% throttle opening. Mine is currently set to 1.8%
- {B1837}: Idle Integral Limit, Upper - This is the upper limit for the integral adjustments. These shouldn't need to be adjusted unless you find the Integral adjustments are running out of adjustment. I've set mine down to 1gm/Sec and not had issues, but it's a smaller engine and smaller cam.
Of course you may be hitting a hard limit as Hymey has mentioned. I've not seen that, but have not been as hands on with bigger cammed cars. Have you logged the cold start with a WB, going from pre-crank to start and the stall issue? I wonder if dynamics is coming in to play? If you send me a log and tune, I'll have a look.
Simon
Good-StdCal_0036.tun
Current tune attached for general abuse
2008 Z06 C6 Corvette
As mentioned the main issue is the transition from cranking idle airflow into idle airflow
Its too fast and too sudden. airflow correction modifier vs ECT doesnt do anything. Im pretty sure its in the Corrections sub container for a reason.. being it multiplies the correction to airflow not the base airflow itself.
2008 Z06 C6 Corvette
OK, try this. I've dropped your cranking air a bit as I think it may have been too much and the ECM is attempting to correct and pulling too much air. I'm also tempted to redo all of your idle correction tables, but should probably see how this first effort goes. I've also played with the dynamics a little in the cold cells and tweaked the min idle airflow. I'd really like to see a log with the WB of a cold start though.
Simon.
Attachment 9444
Just throwing this out there as I have had it happen on 2 different e38 car's. 06 & 09 model
Basically idle is perfect, but if you turn the car off and then go to start it again the car will not idle/fire correctly.
If you attempt to touch the throttle the car struggles to rev or it just dies out as if it's not firing.
I have spoken and sent the tune to Joel to look at and unfortunatly none of the changes made a difference, it's as if the car is looking for the maf on a restart.
If you leave the car off for a few minutes the car will fire straight up.
CLSD, MAF is plugged in but in fail mode.. Hmm maybe I should re-enable it to see if that has an effect.
SwingT Ill try your tune and let you know, thanks. I might have to log o2 mv in lieu of WB as I took it out a while back... its now UK winter, so probably wont get it back in for a while.
2008 Z06 C6 Corvette
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