Cold Start Issue with Timing

[oldstata]

For some reason on cold & warm starts pcm is pulling timing and killing engine unless I give it a little throttle I have looked over everything in the tune and cant find the problem I am new to tuning, I am sure its something simple, So if someone could please review the log & tune & advise me what's happening that would be much appreciated..

2005 Gto Torid Red
408 Stroker 10.3 Cr
Howard Cam
0.625 Int & Exh 284 Int 301.6 Exh 118 Sep
823 Squire port heads built but not ported
SnakEaters 80-lb injectors
Magnuson 2.3 Od cog pulleys 3.0 Front
Innovative West 10% Od 8-rib conversion

[Leva]

Is it pulling timing or oscillating? Post a tune/log. If it is pulling, you prob need to add airflow to your base amd or raise your idle speed. Looks like you have a cam. What your idle rpm set at?

[5FDP]

He did post the tune and logs.

[kevin87turbot]

For some reason on cold & warm starts pcm is pulling timing and killing engine unless I give it a little throttle I have looked over everything in the tune and cant find the problem I am new to tuning, I am sure its something simple, So if someone could please review the log & tune & advise me what's happening that would be much appreciated..

2005 Gto Torid Red
408 Stroker 10.3 Cr
Howard Cam
0.625 Int & Exh 284 Int 301.6 Exh 118 Sep
823 Squire port heads built but not ported
SnakEaters 80-lb injectors
Magnuson 2.3 Od cog pulleys 3.0 Front
Innovative West 10% Od 8-rib conversion

Where are you located? Which MAP Sensor are you using? Your MAP Sensor only reads 83-84 kPa with the engine off. That's pretty low.

[oldstata]

I live in Utah barometric for my area is 12.2-psi or 83-kpa I have a 2.5 map sensor..

[kevin87turbot]

The engine displacement is incorrect in the calibration.

It would also be easier for you to get started by doing a MAF only tune to start with. Just lower the dynamic airflow disable and reenable numbers to a value less than your idle speed...maybe 400 and 300 rpm respectively. Work on your MAF curve to get the fuel trims dialed in. The end point of the low freq table should match the beginning point of the high freq table.

You should half the IVT terms when you double stoich.

Some ID injectors or FIC injectors would help get you get it dialed in better as well.

[oldstata]

I have read that Gm had missed that with the Gto when they put the ls-2 in they left the ls-1 displacement kind of a fun fact thing,, So I did calculate & changed it to the 408-cid then half the IVT.. I am a little confused are you asking about the injector data info, (ID injectors or FIC injectors) I did put the injector data info, in that Snakeaters sent me?? Of course i had to half the flow rate do to the E40 hard limit.. That's funny you mention running a Maf tune because i just did the Maf & Sd thinking it would solve this problem looking at the carts i am fairly close with trims sitting within -4 rich & +4 lean?? Engine runs great other then pcm tanks the timing after it starts?? At first i thought startup flare was causing it but it never reaches that high..

[oldstata]

Update after changing displacement & IVT,, Still having issues I don't think anything changed,, This time i attached a cold & warm start on the warm start it barely managed to stay running the pcm tried like hell to kill it you can see where timing drops into the minus..

[kevin87turbot]

It's certainly got a timing dip after startup. I agree with you...I don't think it's flare control. But, it would be interesting to see if it affects it at all. I would also disable burst knock. I don't think that's the issue either, but it would be a good test.

Do the VCM controls allow you to control absolute timing on the E40?

[smokeshow]

Here's a valuable piece of info: the base spark advance for that short period of time between cranking spark and idle spark is controlled by the main spark tables. Better give them a look.

[oldstata]

Kevin, This morning i did hook up and found in the VCM it will allow me to control absolute timing but only will do negative will not allow positive adjustment tried it just to see it actually didn't change anything,, But it did have spark idle bypass and i tried that but made no difference also still pulled timing i did look at knock burst it is set to pull 12* max the log shows a 27* pull so that cant be it.. Smokeshow, I have changed all timing tables cranking spark and idle spark main spark Hi & Lo octane to the same in the idle area still same problem.. any other suggestions?? attached is current log & tune with all changes made

[APS]

Was this condition resolved? I haven't seen this before and am wondering what the solution was if any.