Help with open loop (cold start) tuning

[12sec.5.3]

When I crank up the engine in open loop (cold) the idle is really low around 500-600 rpm and will not stay running. After I warm it up it goes to my closed loop setting of 850 rpms and is fine. I went through every file I can think of but I can't find the problem.

[Taz]

Hello 12sec5.3,

Post your current tune ... so other Forum members can help ... another pair of eyes often comes up with a solution.


Regards,
Taz

[12sec.5.3]

I'm a little embarrassed but feel free to help with any other issues you may see..
Todd_370_L92_11-16-2010.tun

[Taz]

The tune is far from stock - any modifications to the engine ?? It's a 5.3 L, not a 6.0 L correct ?

Need to know before making / suggesting changes.


Regards,
Taz

[12sec.5.3]

370 cu., l92 heads ported, custom grind comp cam, l76 intake, 42 lb inj., 3600 circle D

[12sec.5.3]

and boltons

[WeathermanShawn]

I'm surprised that your Table B4343 values did not do the trick for you.

You could always try adding 2-3 g/s in this Table. It almost always works. Granted when it starts it may sound like a jet engine if you overload it with too much air..but that Table usually solves the problem..

[12sec.5.3]

I don't know if that table is the cause, but sometimes it idles around 1500rpms for no reason that I can think of. Go drive around a nail it a bit and it stops. idk wt the hell...

[Taz]

WOW !!! That’s a lot of mixing and matching ! WeathermanShawn is our resident idle expert, so you’re in good hands.

Took a quick look, you have the idle learn parameters disabled - B4322 through B4328, I try to leave these active to allow the PCM to assist with changing conditions.

The L76 intake – Holden product or GM truck ? Believe they may have a different volume.

What throttle body are you using with the L76 intake ?

What MAP sensor are you using ?


Cheers,
Taz

[12sec.5.3]

Stock MAP. Holden intake. 90mm ComTech