$8D/manual trans -- oscillating idle only during deceleration when out of gear

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Jun 2, 2011 | 11:01 AM

MonteCarSlow

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Joined: Jun 2001

Posts: 391

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From: Eh?

Car: 1988 Monte Carlo SS

Engine: 5.7L TPI

Transmission: T5

Axle/Gears: 3.73

$8D/manual trans -- oscillating idle only during deceleration when out of gear

Hi.

I just want to throw a hint out there if anyone else runs into a problem I had...

After several years of chasing my tail with a really annoying 'bug' in the TPI conversion of my Monte Carlo, I finally found the culprit of an oscillating idle that I used to get when I shifted my T-5 into neutral while slowing down. Once I was stopped, the idle would instantly stop oscillating.

The fix was hiding at address 0x81E8 where you'll find either 0xC0 or 0xFF depending on your calibration. Mine was set to 0xFF, changing it to 0xC0 cured the problem.

Code:

;------------------------------------------
; IDLE SA PARAMS
;
;------------------------------------------
L81E5: FCB 15 ; 15 SEC, IDLE SA INHIB DISABLE RICH TMR THRESH
;
L81E6: FCB 64 ; 800 RPM, LO GAIN DESIRED RPM THRESH
L81E7: FCB 96 ; 1.2 SEC, LO GAIN XISITION DELAY
L81E8: FCB 192 ; 0.75, LO GAIN UNDER SPD MULT
L81E9: FCB 128 ; 0.5, LO GAIN OVER SPD MULT
;
L81EA: FCB 8 ; 100 RPM REQUIRED RPM OFFSET

Good luck and happy tuning.