Ok so heres my latest list of problems in my never ending quest for the perfect AFR...

As many of you know I was extremely lean on the stock injectors and stock fuel pressure with the RSM reflash on my stage I supercharger kit, so my remedy for this was doing things like GM did. Since the 2003 ecos use the same injectors as the 00+ 2.4s, I swapped to the 2003 Rail system yesterday on my 2002. Now the Gm 2.4 kit also has 4.5psi of boost with 310cc injectors included, im running very close to that pressure wise so I went with the 310s.

Everything was in the car, start it idles rough for a few min holding 11.5 afr idle then backed itself down the normal 14.6, had Rich (Exterminator) from Jersey J's hook up an Autotap OBD2 data logger, took it out for a drive, ran great everytime I planted the throttle it stuck at low 11s on AFR all the way to redline. Also many with larger injectors on ecos have noticed that the ECU tries to bring you back to 14.7 the closer you get to redline by cutting down the pulsewidth (duty cycle). It is my understanding that with the reflash the duty cycle is upped to 80% from the stock 65%. Monitoring the pulsewidths I found this to be true also my pulses were at 16-18ms which is 77-82% duty cycle.

What is not good is that I noticed a max of 6-8 degrees knock retard above 5700rpm, also after running 100 miles the check engine light came on and gave me P0172 which is system too rich, the car seems to have a harder time starting also, its been suggested to me to get an FPR and back off the base pressure a few lbs which I plan on doing but I need to know which one either the accel or the aeromotive will be the easiest and not require any additional parts.

The car this morning also cut the engine off when I was coasting to a stop sign, it refired ok but this has me concerned a bit I need some solutions



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

If you want accel... accell #74566 is the one you need. All youll need to buy is the correct rubber O-ring it doenst come with (stock one has a O-ring built inside it). If you have the 03+ ecotec. The 02 im not sure.

If that link doesnt work for some reason, search it on summit as "accel 74566"

Good luck

im actually going to get the aeromotive



1989 Turbo Trans Am #82, 2007 Cobalt SS G85