Issues with FIC (Fuel Injector Clinic) 1000cc LS3 Injectors - VERY Rich at idle

[Billiumss]

Hello all,

I've tuned a lot of LS combos over the years but nothing with this large of injectors. I'm at a loss with my project. What am I missing here? Ugh....

Here's the specs of my car:

- 2001 Camaro SS M6 (411 - PO1 PCM)

- New Forged LS2 short block

- LS3 Top End 226 232 115 lsa cam

- FIC (Fuel Injector Clinic) 1000cc LS3 Injectors

- Huron Speed Single AC Turbo Kit

- 3 BAR OS with GM 3 BAR Sensor


A few weeks ago, I was at the point in my build where it was time to do some basic tuning so I can drive the car. No matter what I did to the tune, I can't lean it out with these injectors at idle or off idle. I even maxed out the Injector Flow Rate and still runs rich at idle. The AFR is about 10.7 to 11.5 and won't go any leaner. Injector pulse width NEVER goes below 2.3ms, no matter what I do to the tune.

I contacted FIC about it last week and they said to send them in so they could check them out. Mailed them back and they found nothing, they all flowed perfect on their end. Reinstalled them last night and the same thing, very rich at idle.

For break in of the new engine and combo, I reinstalled the stock GM LS3 injectors and put about 50 miles on the car. Drives and idles pretty good with the basic tuning I have done so far. It tunes like you'd expect, got it within 1-2% below 4,000 RPM on the VE table. Runs great in closed loop mode as well.

I used the injector data that FIC has on their website, it really can't get any easier, copy and paste. Done this many times over the years with no issues. Largest I tuned was 80 lb injectors, plug and play no issues. I'm stumped, what am I missing or is the data that FIC provides flawed?

I've attached the file I started with and the log as it was warming up. I did 6 more tunes leaning out the IFR table with scans and had the same results. Any help is appreciated!

THX !

Bill


BTW - Here is the link to the FIC data: http://fuelinjectorclinic.com/hptuners1000Short

[RickClarke23]

You need to go to engine-fuel-transient-transient fuel qualifications and under min fuel milligrams lower it to zero. This is more than likely keeping your injector PW high at idle.

[Billiumss]

Thank you, that worked! My injector ms time didn't go down much, like .2, but that's all it needed to run normal.

Why isn't this info a sticky? I did some more digging and found others with the same problem. Seems some PCM's have a lower limit than others, it's not consistent with GM PCM's of that era.

Maybe the injector companys that provide "injector Data" should provide "all" the data not just 90% of it.

[kingtal0n]

As you learn about new computers (02+) you will see that this isn't the only thing, there are a bunch of 'little things' like this that nobody mentions because its either supposed to be intuitive, 'old info', or a secret/learning curve.

This one I call 'old info' because it isn't really a secret, it isn't intuitive and it would be random chance ("trial and error") not necessarily a learning curve, and the info already exists here, in these gen3/4/5 going back 600pages, this has been covered at least once every 1-5 pages so I would say 600/5 or covered about 120 times to date makes it 'old' information you could have searched.

The idea to take away from this experience is a recommendation: start reading the 'old' stuff because there are 20 other things like this you won't 'know' by intuition or random trial and error.
factory ECU isn't like a stand-alone where all the functions are a clean tunnel vision to the end goal of performance.