here's the scoop, when my motor has been sitting over night and is cold, this is what happens. If i try to hold down the gas the motor just looses vac and just starts stumbling really bad. once the motor has warmed up, it will run perfect! Didn't have any issues on the dyno a month back. I've also been running this "msd" ignition for about a year now with no issues. I'm starting to think it is something with the tune. Maybe some kind of timing or fuel correction vs ECT temp setting is off. Ideas?

I've changed the plugs, tested the spark plug wires, ign rotor, the cap looks fine.

http://www.youtube.com/watch?v=pKDV_i_uk6Y Inside car
http://www.youtube.com/watch?v=zt68Sk1mGzw outside car


Setup:

Neptune RTP
Summit Digital Ign
MSD HVC-II coil

 

Do you have a wideband ?
If not, get one.....

You can't diagnose your issue without knowing what afr ratio the vehicle is running at.

 

i do have a wb. when its stumbling its rich around 12 afr. I'm thinking the ect fuel trim setting would need to be lowered right?

 

right when things sound like they are sounding a little better, it seems though the motor just starts to loose vac and dies out

with the ect around 120, it idles around 13.8 and still stumbles

 

How much vacuum does your motor pull when it is warm at an idle?
Does the car idle by it's self at an idle when it is warm ?

What throttle body are you running ?

 

when its warm at idle, neptune is reading 22-23 in/hg. when the car is warm the motor idles perfect and runs perfect. i'm running the 68mm power products tb

 

I guessing your not throwing any codes correct ?
What are your idle versus coolant temp settings (i.e. 120 deg = 1000 rpms tgt idle)

Something isn't adding up.
Post up your low cam ignition table. (screenshot).

 

here is a link to the cal file

http://www.mediafire.com/?sharekey=0...4e75f6e8ebb871

I'll get a datalog tomorrow. thank for your expert help mtber!

 

How much boost are you running ?
Who tuned your car ?

 

Also, why do you have switch maps enabled ? (You can switch between primary & secondary maps using your ac switch...) This feature is enabled for some reason.

What kind of fuel are you running ?

 

i'm running 24 psi, db performance tuned my car. I was running e85 and reg 92 with my old map sensor. but since then i have upgraded to a 4 bar map and now just running e85. I think we prob forgot to turn that off.

 

here is the data log of the issue

http://www.mediafire.com/?sharekey=4...4e75f6e8ebb871

 

Take the car back to your tuner for diagnoses.
Concerning your ignition maps, they have room for improvement.

 

I figured it out! it was a bad ICM. I had a faulty one before so i made on of those ICM bypass modules for it. I guess it went bad. It's all good now

 

good to hear.