silverTA2002

iTrader: (1)

The idle tuning is getting pretty old. Nothing else was this hard to do.

So far I've....

Set idle to 850
Increased spark at idle to 26 in gear and park
Changed my RAF multiple times based on logs
Leaned out my VE to 75% 400, 80% 800, 95% 1200 rpm
Cranking VE at 90%
Throttle cracker to 75% under 2200 rpms, then back to stock
Changed throttle body set screw to 3% then reset to get 45 IAC count when warm
Moved IAC vs. Effective area table right two places to get desired idle airflow and dynamic airflow to match/cross.

And now the idle is great. Moving IAC table got rid of hanging rpms.

BUT, now it stalls or trys to the first couple times I get going forward or reverse (in a parking lot or driveway, slow mph).

After that, it's completely fine. Startup fine, idle perfect etc.

I've set the cracker to enable at 10mph, and it doesn't seem to want to stall as badly those first couple times, but the "hanging rpm" at 1200 rpm comes back when I'm slowing down out of gear (clutch in), till I stop.

The worst part of it all is that it started up fine and didn't have hanging rpm BEFORE I started "fixing" my idle. It did have the stalling problem though.

RAF, STIT, LTIT, IAC, desired vs. dynamic airflow, all fine. What else is there?

silverTA2002

iTrader: (1)

After changing parameters, am I not giving the computer enough time to relearn idle?

silverTA2002

iTrader: (1)

Someone on another forum suggested this to a guy with a similar problem.

"Assuming you have a Manual transmission go to the throttle follower page: from 10mph and less make change the number to 1.0.

Do this for all 3 tables. First and Second gear only where applicable."

But, this doesn't make sense. There are 4 tables, and the values for Decay and Delay are much different.

APD*98SS

Can you explain what you mean about you Moved IAC vs. Effective area table two places to the right to get desired idle airflow???

silverTA2002

iTrader: (1)

When you open the TB blade a little to let more air in at idle, you have to adjust the IAC vs. Effective area to let the computer know that it's getting enough air.

This lets desired airflow and dynamic airflow values match, rather than being a bit off.

If the values are too far off, the idle will "search" a bit more, and it can cause the cruise control effect (a side effect of opening up the TB blade more).

I got the idea from this thread:
https://ls1tech.com/forums/showthrea...cruise+control

And it worked.


My most recent change has been to make my throttle cracker engage at 10mph and disengage at 9mph.

The car doesn't stall, or drop to 400 rpm when backing up in parking lots any more.

If I go over 10mph in a parking lot, then stop right after starting up, it will dip a little (like 650 rpm), but doesn't come close to stalling like before.

Also, when coming to a stop, my rpms go back to 850 much nicer/ more quickly now. Before, I would have to completely stop to get back to idle, now if I slow below 10mph, it drops perfectly. And above that, it's only sticking at like 1100 for shorter amounts of time.

All in all, much better, but not perfect yet.

After about 40% throttle, then coming to a stop, the rpms did hang at 2000 rpm once for about 5 seconds.

It's getting there. I just think that adjusting the throttle cracker is masking another airflow problem.

RedHardSupra

iTrader: (1)

i actually found a typo in my RAF spreadsheet, i'll post a fixed copy soon.

silverTA2002

iTrader: (1)

Good to know.

Please PM me when you've got an update.

Thanks in advance.

WS6FirebirdTA00

iTrader: (33)

it could be your effective area is off. the stock table is worthless IMO and building your own will help solve a lot of those issues. just take a look at the airflow values for the idle trims and see what is happening.

leave all the throttel cracker and follower tables stock, really no need to mess with them to fix problems like that IMO, although it could be necessary. when does the car do this? hot? cold? all the time?

silverTA2002

iTrader: (1)

It does it at random times. Nothing that seems to be related to temperature of the car.

After driving for a few days, it hasn't tried to stall, and the rpms aren't really hanging, but it seems to be searching for idle a little bit when slowing down with the clutch in.

Maybe it's my RAF table. We'll see when RedHardSupra gets back with me.

Just as a note, before tuning my RAF, at idle with A/C off, my LTIT was about + .50 g/sec, now it's about -0.8 g/sec. I dont' totally understand the RAF part of tuning, since I was just using RedHardSupras spreadsheet.

NAVY

1. In Idle Limiters IAC Park Position: Raise all points for 40C and up to 19
2. Idle Air in Gear: 60C and up to 8.6
3. under Fuel ( or airflow for HPtuners) Main VE Table: Multiply column 400 rpm by 60%. Multiply column 800 by 80%. Multiply column 1200 by 90%.
4. Ignition High Octane Table: Add 2 deg to all points 400 to 1000 RPM, .08 to .32 g/sec

SmokingWS6

iTrader: (1)

Email me your file and i'll take a look at it. stlvortac@aol.com

Josh

silverTA2002

iTrader: (1)

Well.... I've adjusted my RAF multiple times now. My STIT and LTIT are all small numbers now.

But, the idle still freakin floats.

It'll hang at 1000 or 1100 rpm, and go up and down between those numbers and 850 (desired idle rpm) until I go below 10mph (where my throttle cracker disables), then it sets perfectly at 850 rpm.

The idle tuning is so freaking frustrating. This has to be the hardest part to tune right. And, the more I read, the more different opinions there are out there.

silverTA2002

iTrader: (1)

Does anyone know much about the throttle follower decay and delay? Those have been untouched by me.

I should note that the idle is hanging while decelerating, at all speeds (above 10mph), clutch in.

silverTA2002

iTrader: (1)

Oh, just for fun, I set the throttle cracker to enable at 30mph and disable at 29.

Now, under 30mph, it goes quickly and perfectly to 850 rpm. No floating, no searching for RPM.

But, it goes a little too quickly. It makes it a little harder to shift slowly and smoothly from 1st to 2nd.

And, I only drove around the block, but 1 out of 10 times when off the gas, the idle went down quickly, then dropped to about 600 rpm and quickly recovered and levelled off.

When I previously tried scaling down the Cracker table under 1600 rpm, it didn't fix the problem. This makes no sense to me.

On the plus side, it does let me know that it's not an intake leak.

WS6FirebirdTA00

iTrader: (33)

can you post screen shots of your throttle cracker table? as well as your other decay tables for throttle follower. budchevy358@yahoo.com if you want to send a bin file

silverTA2002

iTrader: (1)

I'm not sure how to post screen shots.

But, now, I just tried something a little different (for this trip around the block).

I zeroed out all the cracker values for all mph at 400 and 1000 rpm. Then multiplied the 1600 rpm values by 50%.

Now, the rpms don't drop as quickly, and they don't hang. But, while slowing down, it hunts up and down about 50-100rpm. This compared with 25rpm up and down while stopped, or about the same with cracker disabled.

I think I'm just going to have to mess with the cracker more.

The decay and delay tables are stock.

This is the stock cracker:
0 0 0 0.2 0.358 0.358 0.358 0.358 0.358 0.358 0.358 0.358
0.2 0.2 0.25 0.463 0.463 0.463 0.463 0.463 0.463 0.463 0.463 0.463
0.233 0.3 0.5 0.689 0.689 0.689 0.689 0.689 0.689 0.689 0.689 0.689
0.5 0.5 0.78 0.78 0.78 0.78 0.78 0.78 0.78 0.78 0.78 0.78
0.5 0.5 2.5 2.5 2.5 7 7 7 7 7 7 7
0.5 0.5 2.5 2.5 2.5 2.5 12 12 12 12 12 12
0.5 0.5 2.5 2.5 2.5 2.5 12 12 12 12 12 12
0.5 0.5 2.5 4 6 9 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 2.5 6 9 12 12 12 12 12 12 12
0.5 0.5 3 6 9 12 12 12 12 12 12 12

stock decay (neutral):
0.0049 0.0078 0.0098 0.04 0.0996 0.2998 0.7998 1 1 1 1 1 1 1 1 1 1 1


Stock delay (neutral):
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Delay (gear):
3 2.7 2.4 2.1 1.8 1.6 1.3 1 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8

Decay (gear)
0.0039 0.0039 0.0039 0.0049 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098
0.0039 0.0039 0.0039 0.0049 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098 0.0098
0.0039 0.0039 0.0039 0.0049 0.0098 0.0098 0.0098 0.0146 0.0146 0.0146 0.0146 0.0146 0.0146 0.0146 0.0146 0.0146 0.0146 0.0146
0.0039 0.0039 0.0039 0.0049 0.0098 0.0098 0.0127 0.0195 0.0195 0.0195 0.0195 0.0195 0.0195 0.0195 0.0195 0.0195 0.0195 0.0195

WS6FirebirdTA00

iTrader: (33)

got your email, shot you one back.. looks screwy to me try what i sent

Ragtop 99

iTrader: (7)

Would increasing the airflow on the throttle cracker tables in the 400 & 1000 rpm columns at 12 or 16 mph and below solve this?

WS6FirebirdTA00

iTrader: (33)

his throttle cracker values seem very high to me, mine are all under 1

Ragtop 99

iTrader: (7)

He says his table is stock. Just in the lower left corner the numbers are low so I was wondering if he added .1 or .2. Is that the right theory?