Me and a coupe f buddies of mine recent put in some 42@ svo injector inb my car. I though this would be an easy swap and set what injector siz in the computer. Well we got the injectors in with no problem but when set the computer and then started it. The car is running terribly rich. In the morning You can smell fuel all through the exaust and it even stutters if you dont allow it to warm up for about 3-4 minutes. After its warm up session the car sems to drive fine but when you kinda get on it, its very down on power and it smokes.
My question is do you type in smaller injectors in the in the computer or do you lean it out some where?. All tuning was done via tuner cat.

 

if you need a globel change to lean out the car raise the injecter constant to lean the mixture.most likely this is the isue as fords are rated at a lower fp so it essance you need to have the constant around 46 or just lower your fp some and see what happens
pete

 

Yeah ... what icecold said, SVO injectors are rated at 39 psi while GM injectors are rated at 43 psi ... a 10% pressure difference.

and you may want to check out this link for more tips on tuning ...

http://members.nuvox.net/~on.roz/cars/z28/tuning.html

hope this helps

LWM

 

Thanks for the replys, I 'll go ahead and try that and see what happens. Hopefully tis will be a simple fix. Did the same thing happen to you guys when you put in bigger injectors?. I dont have a adjustable fp reg as Ive heard numerous times the the computer adjust for the raised or lower fuel pressure which is why i have bought one.

 

42 lb/hr SVO (39.1psi) = 44.3 lb/hr @ 43.5psi (stock GM FPR setting)

This site has a lot of calculators, including injector sizing:

http://www.smokemup.com/auto_math/fu...ure_change.php

The PCM adjusts for fuel pressure under closed loop, but not in open loop and at WOT. You definitely want to tune it for your injector size (based on pressure)

 

What most people fail to do (me included) is to change th injector offset vs. Batt Voltage table to the new injector's table characteristics. These values can usually be gotten from the manufacturer. If you don't change these you can always fudge it by changing the MAF/VE tables. Much easier to change the offset tables though.