Ongoing decel to idle stalls

[dnorman7582]

hi, started getting hard to start and stalls on deceleration a couple months ago. Setup was 550/lex afm with safc. Aeromotive Fuel Pressure Regulator, Walbro 255 fuel pump, 3" BIC down pipe, intercooler 18x6x3.5, 3" RSR exhaust, Cometics Metal Head Gasket, ARP Head Studs. Upgraded 57 trim CT.

No error codes...well there were rich/lean codes but I'm pretty sure that was me playing with the afc. None came back after clearing.

Last week I bit the bullet and went with AEM #30-1130 ECM, 3bar MAP sensor, AEM Wideband O2 gauge. Good news is I went from 370 rwhp to 403 hp/447 torque, but...it still stalls and hard to start. By hard I mean maybe 5 to 8 cranks where it use to fire up with a click. I contacted the tuner and he asked me to log some data for him which I will do.

My noob logic tells me this problem has followed over 2 ecu's, air flow vs density, etc. Could this lean us more to a hardware/sensor issue rather than tuning? I hate pissing in the wind, a point in the right direction would be appreciated.

Thanks

 

[radiod]

You 100% absolutely sure you have no vacuum/boost leaks? Check everything from intake piping to each and every vacuum line if you haven't already.

 

[dnorman7582]

Never 100% sure but I've pulled off and blown out vacuum lines, refastened all pipes, removed and inspected accordion hose (Probably should go ahead and replace), AFM is still in but have ordered a pipe to replace it with. VAC is -18 at idle

1 thing worth maybe mentioning is the BOV seems to sound a little weak...not sure how to explain that other than not as solid of a horn as it use to be. But could the BOV cause hard starts and stalls?...only stalls on deceleration to idle, almost every time, coming off boost or not.

 

[radiod]

Vac isn't too bad, normal is between -18 and -20 at idle depending on elevation etc.

Blow off valves can leak, you should notice it if you pressurize your intake piping. Here's a link for a DIY boost leak tester:

http://www.supramania.com/forums/showthread.php?19718-DIY-Boost-Leak-Tester

Make sure you get the right size coupling/adapter to fit your turbo inlet. Otherwise just make sure you don't pressurize your PCV and blow all your oil seals out :icon_razz.