L31 TBI 746 ECM
#1
Member
Thread Starter
iTrader: (6)
Join Date: Aug 2012
Location: TN
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Camaro RS
Engine: L31
Transmission: 700R4
L31 TBI 746 ECM
If you want to read about my swap so far here is the thread:
https://www.thirdgen.org/forums/tbi/...-vortec-4.html
My set up is a DCtrumpet 46 mm throttle body base with New AC Delco 2172286 injectors for a 350. I have a LT4 hot cam, Alex's parts spring kit and a RPM Airgap intake with adapter. I am trying to build my initial start up bin. Fast355 recommended using the LT1 timing table so I have adapted that to my L03 bin here:
I noticed the table only goes to 3600 rpm, does the timing stay the same above that?
Any suggestions what to start with for my fuel table? DCtrumpet told me to set the fuel pressure to 18-20 psi, anything I have to change in the bin to compensate for this?
I have been reading the stickies and using search, there is a lot of good info out there.
https://www.thirdgen.org/forums/tbi/...-vortec-4.html
My set up is a DCtrumpet 46 mm throttle body base with New AC Delco 2172286 injectors for a 350. I have a LT4 hot cam, Alex's parts spring kit and a RPM Airgap intake with adapter. I am trying to build my initial start up bin. Fast355 recommended using the LT1 timing table so I have adapted that to my L03 bin here:
I noticed the table only goes to 3600 rpm, does the timing stay the same above that?
Any suggestions what to start with for my fuel table? DCtrumpet told me to set the fuel pressure to 18-20 psi, anything I have to change in the bin to compensate for this?
I have been reading the stickies and using search, there is a lot of good info out there.
Last edited by Spaceboy1980; 07-24-2014 at 01:34 AM.
#2
Moderator
iTrader: (1)
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 18,400
Likes: 0
Received 215 Likes
on
201 Posts
Car: check
Engine: check
Transmission: check
Re: L31 TBI 746 ECM
Once over 3600 RPM the 3600 RPM row will be used.
With increased fuel pressure the injector offset and multiplier values typically need to be increased.
RBob.
With increased fuel pressure the injector offset and multiplier values typically need to be increased.
RBob.
#3
Member
Thread Starter
iTrader: (6)
Join Date: Aug 2012
Location: TN
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Camaro RS
Engine: L31
Transmission: 700R4
Re: L31 TBI 746 ECM
That is what I figured about the timing table. There isn't very much accuracy there, I guess it is a primitive ECM. Thanks for that info.
As for the offset, I understand what it is but I cannot locate where to adjust it in TunerPro. This is all above my head at the moment but I am digging in. Thanks again.
As for the offset, I understand what it is but I cannot locate where to adjust it in TunerPro. This is all above my head at the moment but I am digging in. Thanks again.
#4
Moderator
iTrader: (1)
Join Date: Mar 2002
Location: Chasing Electrons
Posts: 18,400
Likes: 0
Received 215 Likes
on
201 Posts
Car: check
Engine: check
Transmission: check
Re: L31 TBI 746 ECM
The injector PW multiplier table is at $3E9
The injector offset (bias) is at $2DA
Can search the ECU/XDF in Tuner Pro via the address.
As for the table using the 3600 RPM row when over that, it is that way in all four table directions. Below 400 RPM uses the 400 row.
Same for the columns. The final value retrieved from the table is also interpolated between the row & columns.
RBob.
The injector offset (bias) is at $2DA
Can search the ECU/XDF in Tuner Pro via the address.
As for the table using the 3600 RPM row when over that, it is that way in all four table directions. Below 400 RPM uses the 400 row.
Same for the columns. The final value retrieved from the table is also interpolated between the row & columns.
RBob.
#6
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 9,969
Received 379 Likes
on
323 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: L31 TBI 746 ECM
Trending Topics
#8
Member
Thread Starter
iTrader: (6)
Join Date: Aug 2012
Location: TN
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Camaro RS
Engine: L31
Transmission: 700R4
Re: L31 TBI 746 ECM
I used the timing table from this post of RBob's:
https://www.thirdgen.org/forums/post...606-post3.html
And the ANLU cop car bin injector PW table and offset and came up with this bin. I have hopefully deleted the EGR inside of it as well as functionally deleted the speed limiter.
https://www.thirdgen.org/forums/post...606-post3.html
And the ANLU cop car bin injector PW table and offset and came up with this bin. I have hopefully deleted the EGR inside of it as well as functionally deleted the speed limiter.
#9
Member
Thread Starter
iTrader: (6)
Join Date: Aug 2012
Location: TN
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Camaro RS
Engine: L31
Transmission: 700R4
Re: L31 TBI 746 ECM
Fast, what did you mean by bathtub?
With this ecm, is there anyway to datalog knock counts? I was able to make a history table for blm but when I try to make one for knock it isn't available in the drop down.
I have moved to the vortec timing table due to the car not liking part throttle tip in. Without being able to monitor knock I just feel like the lt1 table is too aggressive.
With this ecm, is there anyway to datalog knock counts? I was able to make a history table for blm but when I try to make one for knock it isn't available in the drop down.
I have moved to the vortec timing table due to the car not liking part throttle tip in. Without being able to monitor knock I just feel like the lt1 table is too aggressive.
#13
Member
Thread Starter
iTrader: (6)
Join Date: Aug 2012
Location: TN
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Camaro RS
Engine: L31
Transmission: 700R4
Re: L31 TBI 746 ECM
I think I found it, I believe OLDPA3 to be knock. I made a table using it and it is filling. Thanks for taking time to help me out.
Thread
Thread Starter
Forum
Replies
Last Post
Glowsock
Tech / General Engine
2
09-11-2015 11:09 PM
Billy Decker
Engine/Drivetrain/Suspension Wanted
0
09-04-2015 03:46 PM