Crossfire to single tbi
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
Should I be upgrading to a 7747 ECM even if I keep the stock CFI system?
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
I did this on Sunday and my idle went to 1500 rpm warm I ended up turning the rear TBI screww down to reduce the idle to 1000 rpm.
What I did not understand is I set the idle speed so that the manometere read 6 inches. Then did the front TBI unit and ultimately end up using the rear TBI unit to reduce the idle speed. Doesn't that mess everything up?
I used the WinAldl software. Interestingly enough it actually smoothed out the car, when connected. Does that mean anything?
What I did not understand is I set the idle speed so that the manometere read 6 inches. Then did the front TBI unit and ultimately end up using the rear TBI unit to reduce the idle speed. Doesn't that mess everything up?
I used the WinAldl software. Interestingly enough it actually smoothed out the car, when connected. Does that mean anything?
IDK why the car ran better with WinALDL hooked up.
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
It SOUNDS like you had the two TB's synched (at your 6"), but the min. air was too high (both TB's open too far). If you changed the relationship between the two TB's after that, then the TB's are not synched...although I don't think perfect synch is as important as some claim. Once the TB's are synched, you want to use the main throttle stop screw to set min air adjustment.
IDK why the car ran better with WinALDL hooked up.
IDK why the car ran better with WinALDL hooked up.
And do I adjust the IAC and then readjust the TBIs witht the manometer to 6" of water?
Thank you
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
Joe
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Block the IAC passages so no air passes
Adjust the main "throttle stop" screw until you achieve 400 RPM idle speed.
Readjust TPS to ~.5v. Your minimum air is set.
Remove IAC blocks and go drive car above 30 mph to reset IAC motors (if necessary).
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
Balance the TB's using what ever method you prefer.
Block the IAC passages so no air passes
Adjust the main "throttle stop" screw until you achieve 400 RPM idle speed.
Readjust TPS to ~.5v. Your minimum air is set.
Remove IAC blocks and go drive car above 30 mph to reset IAC motors (if necessary).
Block the IAC passages so no air passes
Adjust the main "throttle stop" screw until you achieve 400 RPM idle speed.
Readjust TPS to ~.5v. Your minimum air is set.
Remove IAC blocks and go drive car above 30 mph to reset IAC motors (if necessary).
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
http://www.crossfireinjection.net/how_to.htm has a write up on "balance"
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
Someone sent me a procedure
turn on car and paper clip between A & B on the OBD1
disconnect the IACS.
Start the car
set idle 400 RPM
Shut car connect IACs
I did this, set the idle at 600, and after I drive the car I was 1500 RPM at idle.
I have changed the CTS, set the TPS to 0.5 volts. Use the Winalsl software. Does anyone have a way of interperting the data?
turn on car and paper clip between A & B on the OBD1
disconnect the IACS.
Start the car
set idle 400 RPM
Shut car connect IACs
I did this, set the idle at 600, and after I drive the car I was 1500 RPM at idle.
I have changed the CTS, set the TPS to 0.5 volts. Use the Winalsl software. Does anyone have a way of interperting the data?
1st Gear
Joined: Jul 2017
Posts: 1
Likes: 0
I'm not seeing how the IAC would be a problem? I mean yeah, crossfire has two, but they run on the same wires. Plus, you have a base idle already.
Thought I'd go ahead and share what's been done. So I picked up a 1990 K1500 TBI intake from a local junkyard. Removed the old intake and sat the new one in to find that in 87, center intake bolts on the heads were changed to a more straight angle. So I took it back off, and with a drill bit, bore the hole to the correct angle. Then I put the intake back on and tightened it down. Afterwards I hooked everything up to find out that i broke the in-fuel line on the injector pod. So I'm waiting on a new throttle body as we speak. As for the air pump problem, I had already remove it and ran a shorter belt, so no worries there. And for the air filter, I have about an extra 3-4" of clearance because there is a hole in my hood underneath my hoodscoop for fresh air. Anyone want a crossfire intake?
Thought I'd go ahead and share what's been done. So I picked up a 1990 K1500 TBI intake from a local junkyard. Removed the old intake and sat the new one in to find that in 87, center intake bolts on the heads were changed to a more straight angle. So I took it back off, and with a drill bit, bore the hole to the correct angle. Then I put the intake back on and tightened it down. Afterwards I hooked everything up to find out that i broke the in-fuel line on the injector pod. So I'm waiting on a new throttle body as we speak. As for the air pump problem, I had already remove it and ran a shorter belt, so no worries there. And for the air filter, I have about an extra 3-4" of clearance because there is a hole in my hood underneath my hoodscoop for fresh air. Anyone want a crossfire intake?
