Cam Surging... please H E L P
12-26-2003, 10:23 AM
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Cam Surging... please H E L P Just built finished with the motor in the Vette and the cam (228/232) will idle but only after surging up and down between 400-1200rpms four or five times.... only reason it isn't stalling now is probably because I raised my idle to 900rpms with LS1 Edit. Are there any settings on LS1 edit I can change to help this problem?? It also smells very rich at idle...?
Thanks for any help! - Dan
Thanks for any help! - Dan
12-26-2003, 11:05 AM
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you need to play with the IAC(not sure on vettes), the RAF (airflow in gear and neutral) as well as add some timing to idle, reduce VE at 400-1200rpm.
QUOTE
originally posted by NoGo on ls1tech.com
Here are some things you can try.
Idle Limiters --> Idle Speed: 950
Idle Limiters --> IAC Park Position: Raise all points from 40C and up to 21
Idle Limiters --> Idle Air In Gear: All points 60C and up to 8.6
Fuel --> Main VE Table: Multiply column 400 rpm by 60. Multiply column 800 by 80. Multiply column 1200 by 90.
Ignition --> High Octane Table: Add 2 deg to all points 400 to 1000 RPM, .08 to .32 g/sec
Once done with this program, start the car and check for surging. If the car surges, unplug the IAC and see if the surging stops. If the surging stops follow below.
Idle Limiters --> Idle Air in Gear --> All points above 60C to 9.2
Take the car for a drive and check your idle. If the car goes on cruise control reduce the Idle Air in Gear Table .2 (further if necessary). If the idle holds at 2000 RPM for extended periods of time reduce the P/N Airflow Decay table for all points above 10 MPH by 5% (multiply by 95) until this stops. Be vary careful on this table.
If car keeps surging with the IAC unplugged two more things to try.
Multiply Main VE table by another 95% (total reduction of 85%). Repeat until the surging goes away, or until the car begins to hesitate when you take off.
High Octane Ignition Table. Reduce timing for all points 400 to 1000 RPM, .08 to .32 g/sec by 2. Repeat, but don't reduce it any more than 6 degrees.
If your car still doesn't idle after this, then you have other problems, and should start looking elsewhere.
Nice site for tuning.
Charlie.
QUOTE
originally posted by NoGo on ls1tech.com
Here are some things you can try.
Idle Limiters --> Idle Speed: 950
Idle Limiters --> IAC Park Position: Raise all points from 40C and up to 21
Idle Limiters --> Idle Air In Gear: All points 60C and up to 8.6
Fuel --> Main VE Table: Multiply column 400 rpm by 60. Multiply column 800 by 80. Multiply column 1200 by 90.
Ignition --> High Octane Table: Add 2 deg to all points 400 to 1000 RPM, .08 to .32 g/sec
Once done with this program, start the car and check for surging. If the car surges, unplug the IAC and see if the surging stops. If the surging stops follow below.
Idle Limiters --> Idle Air in Gear --> All points above 60C to 9.2
Take the car for a drive and check your idle. If the car goes on cruise control reduce the Idle Air in Gear Table .2 (further if necessary). If the idle holds at 2000 RPM for extended periods of time reduce the P/N Airflow Decay table for all points above 10 MPH by 5% (multiply by 95) until this stops. Be vary careful on this table.
If car keeps surging with the IAC unplugged two more things to try.
Multiply Main VE table by another 95% (total reduction of 85%). Repeat until the surging goes away, or until the car begins to hesitate when you take off.
High Octane Ignition Table. Reduce timing for all points 400 to 1000 RPM, .08 to .32 g/sec by 2. Repeat, but don't reduce it any more than 6 degrees.
If your car still doesn't idle after this, then you have other problems, and should start looking elsewhere.
Nice site for tuning.
Charlie.
