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Re: Vn v8 cammed stalling when put into drive

Posted: Mon Jun 28, 2021 8:01 am
by vp304
Thanks for the extra info guys will give it all a go this weekend coming up when i can get to the car again

Re: Vn v8 cammed stalling when put into drive

Posted: Mon Jun 28, 2021 8:15 am
by 'quipt4it
VK_3800 wrote:...I can't see it being a fuel issue with a small cam like that? ...
I can.

OP stated that this is a transient/ occasional event. It happens when the engine is warm. He made a typo in his last post (about cold).
vp304 wrote:...Tho has this odd time when you start it only when warm put into drive it just stalls straight away...
The timing doesn't change in the time-frame mentioned, but the fuelling does.
When pulling the trans into gear the load on the engine increases, hence the occasional stall.
OP has already been suggested to increase the timing, to a figure to 'at least' 25-26 degrees, and to match both the Idle Spark Map to the Main Spark Map to ensure a smoother idle and to improve that transition from Idle to Drive.
We are not exactly 'grading' cams here... :)

Re: Vn v8 cammed stalling when put into drive

Posted: Sat Jul 03, 2021 7:17 pm
by vp304
So played around with the car today pumped it up to 24 deg on the idle timing map and around 24 deg were it idles at in drive on the main timing map in the 400 800 rpm area.
Was still crappy actually got a bit worse. I was scratching my head at this point.
So i bumped the in drive rpm from 750 to 775 got a bit better.
I then realized when in park (aftermarket shifter) in tuner pro its not showing up that its in park so is idling at 775 rpm (in park) when moving selector into drive it dips way to much and stalls.
Owner of car then said oh yeah i cant start car in park (only in neutral) so i told him to fix shifter issue up.

When in neutral revs rise to 850 rpm or so and it drops into drive no worries.

Re: Vn v8 cammed stalling when put into drive

Posted: Sat Jul 03, 2021 8:55 pm
by delcowizzid
If you add to much timing to the idle map the idle spark correction can't raise rpm by adding any extra timing to prevent stalling and has to end up moving the slow reacting iac to catch any rpm drops after its tried adding spark. Not having the park neutral switch working is your main issue though as it won't preemptively add iac steps when shifting into gear

Re: Vn v8 cammed stalling when put into drive

Posted: Sat Jul 03, 2021 10:01 pm
by vp304
Thanks for the info delcowizzid.
For stock 5l with cam just over 220 duration would 24 deg be ok for idle timing or should i drop back to 22deg like how it was before ?
Should i just try around that range and see what gives the best idle vacuum ?

Re: Vn v8 cammed stalling when put into drive

Posted: Tue Jul 06, 2021 9:33 am
by hsv08
vp304 wrote:Thanks for the info delcowizzid.
For stock 5l with cam just over 220 duration would 24 deg be ok for idle timing or should i drop back to 22deg like how it was before ?
Should i just try around that range and see what gives the best idle vacuum ?
Normally the Vacuum method works ok, but youd find where your highest vac is, then knock a couple degrees out so as Delcowizzid has mentioned, the adaptive spark can pickup the shortfall with timing ( if your at MBT timing at idle, it means if it attempts to add more, its only going to reduce overall torque)

So set it back to whatever felt better, then get the shifter sorted so it will attempted to preemptively add IAC steps, and use left over timing to catch if it needs to.

Re: Vn v8 cammed stalling when put into drive

Posted: Tue Jul 06, 2021 2:23 pm
by vp304
Thanks hsv08
On the weekend i gave it another go dropped 2 deg of (the idle timing map) to were it was back before.
Also made sure it blended well of the idle map onto the main map for timing
Fixed the park switch on the aftermarket shifter.
This allowed me to drop the idle in drive rpm by 25rpm lower
and in park another 25rpm lower.
So far is looking a lot better. Will give it a couple of weeks to see how he goes with the car.

Thanks