Injector change and tuning?
Thread Starter
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Injector change and tuning?
My first post in this forum
I am changing the injectors in my 93 stock LT1 to FMS 24# and know about the closed loop/WOT issues with them running rich. I have had several suggestions as to how to fix the problem:
1. AFPR-read both good and bad about using this method even read that all that happens is ECM learns to adjust but it still runs rich.
2. Chip burn-about twice as expensive ($250) but I think it is a little excessive to change 1 parameter.
What are my best options on how to fix the rich problem in your opinion?
I am changing the injectors in my 93 stock LT1 to FMS 24# and know about the closed loop/WOT issues with them running rich. I have had several suggestions as to how to fix the problem:
1. AFPR-read both good and bad about using this method even read that all that happens is ECM learns to adjust but it still runs rich.
2. Chip burn-about twice as expensive ($250) but I think it is a little excessive to change 1 parameter.
What are my best options on how to fix the rich problem in your opinion?
Burning Brakes
Joined: May 1999
Posts: 760
Likes: 1
From: Greenwich, CT
The Inj constant is used in the ECM for fuel calculations. A brief discussion
of fuel metering was placed here a year or so ago:
http://forums.corvetteforum.com/showthread.php?t=689344
While that thread is concerned with fuel calcs in the $8D mask, I believe the
SD LT1 program is functionaly similar.
Considering that the ECM depends on a very precise fuel calc for every mode
of engine operation, the proper answer is to give the computer the RIGHT data
with which to operate.
Trying to kludge the ECM with an AFPR introduces volumetric flow changes
that will only need to be corrected somewhere else in the program, at much
greater effort.
For the Bosch 24# (SVO) injectors, use ~ 25.5 lb/hr for the constant with stock
rail pressure. While those injectors have a little different latency (coil inductance)
than stock, the effect is small.
Several people on the board have offered to make minor PROM changes for free
in the past, provided you buy the parts. Changing the constant takes about 2
minutes, including the chip burn. Perhaps one of 'em will see your post.
of fuel metering was placed here a year or so ago:
http://forums.corvetteforum.com/showthread.php?t=689344
While that thread is concerned with fuel calcs in the $8D mask, I believe the
SD LT1 program is functionaly similar.
Considering that the ECM depends on a very precise fuel calc for every mode
of engine operation, the proper answer is to give the computer the RIGHT data
with which to operate.
Trying to kludge the ECM with an AFPR introduces volumetric flow changes
that will only need to be corrected somewhere else in the program, at much
greater effort.
For the Bosch 24# (SVO) injectors, use ~ 25.5 lb/hr for the constant with stock
rail pressure. While those injectors have a little different latency (coil inductance)
than stock, the effect is small.
Several people on the board have offered to make minor PROM changes for free
in the past, provided you buy the parts. Changing the constant takes about 2
minutes, including the chip burn. Perhaps one of 'em will see your post.
Pro
Joined: Sep 2001
Posts: 542
Likes: 1
From: Stuck in the 80's
Originally Posted by DOCTOR J
Several people on the board have offered to make minor PROM changes for free
in the past, provided you buy the parts. Changing the constant takes about 2
minutes, including the chip burn. Perhaps one of 'em will see your post.
in the past, provided you buy the parts. Changing the constant takes about 2
minutes, including the chip burn. Perhaps one of 'em will see your post.
