2000 firebird with an F1C procharger 20 PSI and forged 347. car has 60# INJ and twin 255 intank pumps . at 5800-6500 RPM the car leans out to 12.5-13 although the fuel pressure stays steady at 70 PSI..it made 589 RWHP and injector Duty reached 180%
2000 firebird with an F1C procharger 20 PSI and forged 347. car has 60# INJ and twin 255 intank pumps . at 5800-6500 RPM the car leans out to 12.5-13 although the fuel pressure stays steady at 70 PSI..it made 589 RWHP and injector Duty reached 180%
Last edited by Street Legal; 10-28-2008 at 02:18 PM.
any one
Could be a few things but the first things I would look at is possibly undersized injectors & too rich of an afr. If you know fuel pressure is steady at 70psi at the rail its probably one of the two aforementioned.
You might want to post your .hpt file as well. Injector duty cycle is simply a calculation of injector pulse width, if some of your tables had to be fudged this can throw off the IDC calculation.
It doesn't have to be perfect, it just needs to be done in two weeks...
A wise man once said "google it"
Post a log with the AFR connected as well...
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
not matter what the comannded A/F is or how much i increase the VE values A/F wont change from 5800-6500 it leans out to 13.maybe something wrong with the engine it is using a lot of fuel to make 580 only lol
starts at 11.8 from 3000-5500 then leans out
Post your tune. If the VE is too high it can cause the same issue.
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
20 PSI off a blower? Wow.
One possibility is incomplete combustion,
if it isn't all burned the oxygen left unused
will be seen by the WBO2 sensor. If you
have a very high octane maybe burn time
(to completion) may exceed power stroke
time?
Is the 13:1 AFR coming along with any
ping / lean plug appearance, any problem
for the motor or is it just an instrument
reading?
If AFR moves linearly with RPM after
being flat in the lower range, then maybe
it is a "ain't no more to give" problem.
With the duty over 100%, 100% is all
you get and fuel delivery stays flat while
airflow rises, right?
But duty goes like 1/RPM and 180% would
mean you're limiting by like 4000RPM?
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