Odd Cold Start up Issue

[PNW LSC]

My '95 GT is having a weird problem on start up. This problem came about after some tuning with my TwEECer to get it running right after a head swap (Trick Flow Twisted Wedge heads, Cobra intake, 24lb injectors, stock cam and MAF). I tuned it to run correctly with the stock MAF and bigger injectors. However when I start it after it has been sitting overnight it will idle erratically about 5 seconds after it fires and last for about 20 seconds, sometimes less. It starts to happen as the RPMs are dropping from initial start up and it gets closer to 1000RPM. Then it surges between about 900RPM and 1300RPM for a little bit, then it steadies and idles fine. I have adjusted the IAC and throttle stop according to the instructions outlined in one of the threads here. After letting it finish doing this it'll idle fine and run without any other issues until I let it sit long enough to cool down completely.

Anybody have any idea what's going on at start up to cause that? Thanks in advance!

 

[PNW LSC]

Anybody?

 

[urban96]

bump, Ive been having the same issues....


I need to get another bung welded into the exhaust and put my wide band in there and see whats going on.

 

[final5-0]

I'm sure you upped the inj size in high and low slopes

I'b bet you did not take in account for cold starts with the larger inj's

Sorry I forget the table name but it works off time/temp and these values
get added to the regular fuel table

Basically, as time and or temp rises, the values that get added become
smaller and smaller thus the ratio becomes leaner and leaner

Of course ... the fix is to lower those values accordingly

Or you could look at it like an electronic kinda choke

Then again ... peeps these days ... Just might not know what a choke is

I feel bad about not remembering the table name
but
I have posted specific details on here before if you wanna search

I might have some stuff on my site about it
but
I don't remember about that as well

Grady