wrong injectors maybe

[minytrker]

I went to tune a 99 Z28 today that has all bolt ons, heads, cam, ls6 intake and differnt injectors. Here is the catch, the guy swapped the ls6 intake and fuel rails off a 02 SS which I was told had bigger injectors. This car is untuned, and nothing has been changed. If it went from 24lb, or 26lb injectors to 28lb injectors would the car still start and run? The owner is going to pull the injectors and check to see if there are some number on them. The car was very lean at cruise or driving 19 afr and would get down in the 10-10.5 afr at wot. The injector duty cycle was going as high as 128% in the 6,000 rpm range. The car making est 450-480rwhp. If the injectors have been changed to 28lbs how do I fix it? I just know they would be stock 28lbs injectors.

[Tordne]

Just take the injector tables form a 02 Camaro tune as they will be scaled correctly.

The 19 AFR wouldn't happen to be DFCO would it?

the very rich WOT would also suggest that the injectors larger than stock (or at least larger than in the tune). Don't worry too much about the duty cycle % until you have the correct tables as that is simple a calculated value.

[minytrker]

[QUOTE=Tordne]The 19 AFR wouldn't happen to be DFCO would it?

QUOTE]
I dont think so. If the injectors were changed would it even ahve ran? Also when I went to SD to do auto tune the car ran really bad and wouldn not idle and serged also. WOuld those be any signs of the wrong injectors?

[ringram]

Sounds like it. I would quite likely run on wrong injectors.
As tordne says put the IFR table from an 02 SS in there it will have the correct values and go from there.

[TAQuickness]

I went to tune a 99 Z28 today that has all bolt ons, heads, cam, ls6 intake and differnt injectors. Here is the catch, the guy swapped the ls6 intake and fuel rails off a 02 SS which I was told had bigger injectors. This car is untuned, and nothing has been changed. If it went from 24lb, or 26lb injectors to 28lb injectors would the car still start and run? The owner is going to pull the injectors and check to see if there are some number on them. The car was very lean at cruise or driving 19 afr and would get down in the 10-10.5 afr at wot. The injector duty cycle was going as high as 128% in the 6,000 rpm range. The car making est 450-480rwhp. If the injectors have been changed to 28lbs how do I fix it? I just know they would be stock 28lbs injectors.

yes it will run. pig rich, but it will run. I upgraded from stock 26's to the Racetronix 32's in my sig and she fired up and ran.

[minytrker]

Thanks alot, I always thought it wouldn't even run. I will try the ss injector tables.

[Redline Motorsports]

Even at 28 lbs you do not have enough injector to safely fuel that motor. Don't waste your time! I would a install a set of #30's or 42's and rescale them from scratch.

[foff667]

Even at 28 lbs you do not have enough injector to safely fuel that motor. Don't waste your time! I would a install a set of #30's or 42's and rescale them from scratch.

werd...a couple of side notes 99's had 26lb injectors...24's were only used on lt1's from my knowledge...ls1's always had either 26 or 28lb injectors. Also as long as the maf is on, connected, & working it will always try to get to 14.7:1...with working o2 sensors it will do a pretty good job of compensating for a switch from 26 to 28lb injectors and you SHOULD run at 14.6-14.9:1 via a wideband at part throttle & idle. WOT will be a different story. If your part throttle is at 19ish theres either something else wrong or your wideband is fubar'd