I am trying to get rid of an idle dip when coming to a stop. Attached are:
Tune
.CFG
Log
Unfortunately I did not have speed loaded in my .CFG nor did I have the wide band turned on, I will add these on my next log.
Watch throttle % as I am not providing any throttle input during the idle dip, that is just me letting off coming to a stop (log is mostly parking lot going over speed bumps). You will see every time TPS goes to 0% RPM dips to +/- 500rpm. It holds idle fine once it recovers from the dip.
IAC is fairly constant at +/- 65 counts
I think the only reason it is not stalling is due to the high commanded timing at 400 and 600 RPM's.
AFR is basically stoich at idle (verified when WB is plugged in).
If I up base idle timing much from here I can't keep idle RPM where my buddy wants it.
Stock LS6 bottom end
Fast 102
AI LS6 heads
226/232
1 7/8 headers
3" X-pipe
6 speed car
i had very similar problems, i used the throttle follower with greater multipliers at 1200 rpm down to 0, and slowed follower decay,
numbers to high in follower will cause idle to hang just above desired a little before returning to complete idle, so some trial and error may be required
also your ign timing has huge steps in it that will dramatically bother idle condition, set idle timing timing to 28 degrees from o g/cyl down to .32 g/cyl as well as 0-1200 rpm
to from a big flat square as such in the top left of the table, match your hi-octance and idle advance tables in this area,
bear in mind that file has a whole handful of idle parameters that differ from factory so other then idle timing and throttle follower use caution,
use compare in scanner and look at these two areas, change timing first then move to follower multiplier and decay
these are two things i have determined work best following having a whole bunch of cars with idle problems similar
Thanks for the info.. I had commanded timing set to 28* for 400-1200 at .08 - .44 previously. It had a real hard time staying lit when coming to a stop and could not get the desired Idle RPM.
I can get the desired idle RPM with the lower commanded timing but the stalling was even worse. By bumping the 400/600 fields up, it really helped to catch itself more often.
I did screw with throttle cracker and rolling idle some before reading your reply and got it much much better. Then I stumbled on another issue that was not helping.
When the car got wired (I did not do it) it got a 2 relay set up for the fans and I did not catch that both low/high speed was commanded on at the same temp. This large current draw when fans came on were not helping the situation. Car was just rewired to a 3 relay set up and fan on/off for low/high were adjusted. Did not get to drive yet (raining) but just idling cycling the fans low/high/off, it is way better.
The only thing I am fighting now is getting proper fan operation (low speed) when AC is turned on. The car has a:
Vintage air unit
12v from the compressor to PCM Red 17
Resistor jumping Blue 45 to Red 14 to simulate the factory pressure switch (but only reporting 1.7v)
Idle is commanded higher when AC is armed (like it should)
I get no low speed fan turning on unless I alter fan AC pressure settings. But when I do hit the "ok" threshold, low fans are always on even when AC is turned off....
Thinking my work around here is to wire in 1 more relay:
85 from AC compressor 12v
86 to ground
30 from Blue 45 (5v reference)
87 to Red 14 but with a resistor stackup to simulate the 1.9v that should be seen when AC high switch would normally be present.
my fans (2 rad and one condensor) all come on at the same time using hi-temp trigger,
when the a/c kicks in it engages the fans as well, i have done a handful of different engines with various cam shafts and intakes etc with out fan contributing to engine stalling as such,
where is you fan air g/sec set?
using the scanner, without ac on and engine running near operating temp. command the fans on and take notice of what your stit does
do you have a wb?
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