Stop Sign Stall - SOLVED

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Stop Sign Stall - SOLVED

Unread postby 89FiveOh » Tue Mar 20, 2018 11:55 am

Hello,
After fighting and fighting and fighting with the HATED stop sign stall. I kept increasing and increasing DASMIN. This would raise my idle and hold it to a higher rpm until I fell below my MPH in order for idle to settle into NUBASE. My thinking which to increase the available rpm before DASHPOT expired would allow some xtra air to catch the rpms on the long approach to a stopsign.

Nothing worked! However today, I noticed that the increased air I was getting from raising DASMIN was not fully exhausted before my idle fell below my NUBASE. With a little finesse, I was able to LOWER Dasmin to the point that at the time at which DASHPOT decayed to 0, the rpms were in the range for the ISC to catch and control idle.

So in my case, LOWERING actually helped me here as with most writeups and suggestions INCREASE is a most common reply to a problem.

Maybe someone can verify my thinking, the OL process of the idle control, (ie the decay of the daspot/dasmin) was draining the rpms too low that when CL takes idle back over, the ISC just couldnt catch it.

thanks
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Re: Stop Sign Stall - SOLVED

Unread postby SlowBox » Tue Mar 20, 2018 2:58 pm

Dashpot decaying too slowly can cause just as many headaches as it decaying too quickly. I think there is a scalar specifying at what rpm the computer is allowed back into idle mode, but I can't say exactly which one. Maybe turning it up a little would help get stalls and surges better under control? I'm certain Decipha will school us when he gets a chance.
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Re: Stop Sign Stall - SOLVED

Unread postby 89FiveOh » Tue Mar 20, 2018 3:35 pm

I happened to notice that there was still a small balance of air still bleeding off while my rpm continued to fall past NUBASE. As long as there was any decay happening while my RPMs were at or near idle, Id stall every time. Once I got it to decay all my dashpot within 50 -75 RPM before hitting NUBASE, it never missed!

Its almost as if until the daspot decayed to 0, CL was not allowed to be entered. An by the time daspot had decayed, the isc could not bring the rpms back into correction.
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Vehicle Information: 1989 Mustang GT
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MOATES QuarterHorse
308
Custom Cam (HR)
AFR 165, 58cc
BBK 75mm (24lb/hr calibration) MAF
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3.73 gears
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Full length BBK headers with H-pipe thru Flowmaster mufflers

Re: Stop Sign Stall - SOLVED

Unread postby SlowBox » Tue Mar 20, 2018 3:59 pm

I've experienced the same thing and came to the same conclusion about idle control. Maybe we'll both get answers.
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Re: Stop Sign Stall - SOLVED

Unread postby 89FiveOh » Tue Mar 20, 2018 4:11 pm

It very well could play a roll in surging. When I was dialing in the dasmin scalar, I got surge like clockwork when the complete decay of daspot happened around 200 - 150 BELOW idle. At that point I suppose the ISC multiplier vs RPM was able to kick in and buzzed the rpm back up and to the other multiplier point in the table, therefore creating this oscillating mess.
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308
Custom Cam (HR)
AFR 165, 58cc
BBK 75mm (24lb/hr calibration) MAF
5 speed
3.73 gears
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Full length BBK headers with H-pipe thru Flowmaster mufflers

Re: Stop Sign Stall - SOLVED

Unread postby decipha » Tue Mar 20, 2018 9:41 pm

i posted this in the bracket racing thread the other day, it applies here

also another good thing, it makes for a much nicer transition for the dashpot min clip if u set dasmph to 0.5 mph and set dasmphhys to 12 mph, that way when u let off the brake and idle in gear dasmin doesnt take over and drag u forward til u get over 12.5 mph which u shudnt at closed throttle, then dasmin will kik n and let it coast down to 0.5 mph before decaying dasmin out making for a very nice and smooth transition

set minmph and mphctl to 25 mph, as well as setting dasctl to 0.35 and make sure you dont dasmin clip above .35

I've been setting idle like that for the last couple years now and its always perfect!!

the issue your having is that you have dasctl set too low so its not entering closed loop idle control with dashpot still in it

viewtopic.php?f=18&t=2699
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Re: Stop Sign Stall - SOLVED

Unread postby 89FiveOh » Wed Mar 21, 2018 7:45 am

Thanks. I cant seem to find the scalar DASCTL. Perhaps you may know another name? This scalar allows CL control to take over even tho DASPOT hasn’t expired?
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Custom Cam (HR)
AFR 165, 58cc
BBK 75mm (24lb/hr calibration) MAF
5 speed
3.73 gears
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Full length BBK headers with H-pipe thru Flowmaster mufflers

Re: Stop Sign Stall - SOLVED

Unread postby decipha » Wed Mar 21, 2018 9:24 am

i have the description in the dashpot write up
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91 4r70w - Skarlett
92 (2x) 5spd & auto - Bianqa, Andrea
93 auto - Danika
94 5spd Rionda
95 auto Aisha
Vehicle 2 Information: Others:
00 Lincoln LS - Luanda
98 Camaro SS - Bounquisha
02 Harley F-150 - Sasasha
03 Marauder - DyShyKy
00 Explorer 5L - Bernyce

Re: Stop Sign Stall - SOLVED

Unread postby ozcob » Fri Mar 23, 2018 1:00 am

'set minmph and mphctl to 25 mph'

Decipha - is 'MPHCTL' correct - and is it available in all strategies?

If not is there an equivalent in CBAZA?
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