Another_User

Yes, it helped on mine. Part of why I initally thought it was strictly fueling. I don't think the car liked the differences in fuel trims between the idle tables and the normal tables. Sometimes the STFTs take their sweet time adjusting. VE Tuning went a considerable amount easier after I disabled them. My low end bucking was not helped, just my cruise bucking.

Cal

iTrader: (1)

Is there any way to disable idle proportional fueling with LS1edit?

Another_User

Not that I have ever heard of. Didn't they just release a new version though?

ArKay99

iTrader: (1)

Not yet Cal. The car has been in hibernation since late December. Won't come out for 4 more weeks. Ground hog saw his shadow... . Anyway, when I do bring it out I'm pulling the heads, redegreeing the cam, and putting on an LSX manifold with a NW 90mm tb.
I have purchased the upgrade to EFILive and have been looking at some very interesting stuff on my buddies 2000 h/c FRC. We have made a map to get the averages of the IAC (Running Air Flow) table. We set the table up in 20C increments and MAF g/s and logged a bunch of closed throttle situations. We then plugged those averaged values into the RAF table and things got very smooth. No surging or bucking. I can't wait to do this on my car, but it probably will be a totally different beast by then.

P Mack

iTrader: (6)

Does idle proportional even matter if you're not in an idle ftc?

WS6snake-eater

I would be very interested to see how you did this, perhaps some screenshots, or a detailed explanation.

SideStep

I am really interested in this... I am installing a F13 (112 +4) this weekend...

ArKay99

iTrader: (1)

If you have EFILive then you can do this. Not sure how to do it on HPTuners.
1: Select the Maps tab and find an open slot for a new map.
2: hit Ctrl+Enter to open up the 'Create new map' dialog.
3: In the Data tab select Desired IAC Air Flow (Grams/s)
4: In the Column tab in the Column: drop-down select Engine Coolant Temperature (*C)
a) Set the Columns: to 10
b) set the Col labels to: ,-40,-20,-,20,40,60,80,100,120,140
5: In the Row tab in the Row: drop-down select Air Flow Rate from Mass Air Flow Sensor (Grams/s)
a) Set the Rows: to 1
b) set the Row labels: to ?,400
6: Save as GM.IACDES_B Grams_s.map

Make sure those 3 pids are selected to scan with and start your car cold and start logging immediately. Let it warm to operating temp and log for a couple of minutes longer.

You can see the map filling with values as you go along. Then copy the Average values into the Idle/Idle Airflow table. These values will be the average desired running airflow values for that table. Then you can start fooling around with the Idle Airflow Parked table. (the above procedure was described by Nick Williams and Bink-being careful to give credit) This is a great starting point to get the idle transitions in line. What seems to be the underlying problem all on this thread are concerned with is the bucking and surging. These are byproducts of idle transition not performing well due to inaccurate RAF values. This causes theTB blade to servo open and closed to try to find where it should be and what it wants to be. If these values are off by only a tiny bit this servoing will continue. I can say this worked well on BLACKTOP2000's car. I haven't tried it on any others so I can't say this is a cure-all, but it makes sense to me. I wish I had more experience on this to relate though.

gojo

iTrader: (12)

Arkay,
Here's the thread describing the procedure.
https://ls1tech.com/forums/pcm-diagnostics-tuning/267674-idle-transition-tuning.html

The solution to surging and cruising is often more simple than what I've been seeing done. Note in the writeup the importance of getting Idle Airflow Parked (IAC Park) correct. Often, changes in intake air temperature is the culprit. If you had Idle Aiflow Parked set perfectly (not likely) that would be actual airflow and is what is expected by the PCM. That is one cause of the TBlade hunting.

Bink

Sorry, not me.
gojo and Nick are the brains behind the Idle tables and the 90 mm TB.

gojo

iTrader: (12)

Since we are all being humble, Nick is the brains and I am a sort of consultant, test mule.
We all contribute Joel. These Forums are terrific.

P Mack

iTrader: (6)

I thought we determined that the IAC wasn't causing the bucking problems. Another User said with the IAC locked it didn't make any difference. If that's the case, the RAF table would have no effect.

WS6snake-eater

Many think that the MAF is the root of all evil...I think it is the RAF.

WS6snake-eater

I understand your method and it looks pretty solid. I guess I will have to come up with a way to do this in excel with my HPTuners. You mentioned that after the RAF is dialed in that you will need to move onto the IAC park; has anyone come up with a how to for the park postion?

ArKay99

iTrader: (1)

Thanks gojo. I saw a copy of that thread on another forum. I was trying to relate to Snake_Eater how to build a MAP. I am now on to the IAC PA\arked table and approaching it with intake air temp as opposed to ect as I 'assumed' it was. I was a victim of very little documentation as I suppose a lot of us are. As more of these 'undocumented' functions become defined I am sure there will be less confusion as to what parameters are significant for the table in question, not to mention what the table in question is used for.
Sorry for putting you in the spotlight joel, I was winging it from work here and thought you were involved. BTW, you HAVE helped me quite a bit in the past so why not take a bow.
BTW, All this undocumented and misdocumentation reminds me of Windows programming...

DVCrazyCamTAWs6

iTrader: (6)

I'm going to try messing with my timing.
I've tried playing with the airflow seems to help but then i no longer needing my accel. pedal. car moves along on it's own.
I got about 32+ degrees of overlap and i'm surging at like 50

gojo

iTrader: (12)

I would start with stock IAC values, if possible. By moving IAParked up you move the IACDES g/s up and vice versa, in order to match the IACDES values to MAF values. The IAPark table is setup by temps 0-20-40-60 etc. So, for ex., if it's cold out and your IAT stays between 0-20 you can tweak the idle airflow(RAF) values to fix any stumbles as the ECT goes up, in that IAT range. This is the tedious part because you will likely also have to make small adjustments to IAParked for different IAT days. If you find that at any particular IAT the car does well, all through warmup, when driving, then only IAParked is left to fix.

As for the logging to Excel: With HPT and also before EFI had Maps you set up logging IACDES, IAT, ECT, MAF and/or Dynair if you need. Then just scroll though the results on the logger page and jot down the values to match. It's not a bad way to do it, since the averages are just that.

Arkay, Edit refused to correct having nothing indicated. EFI and HPT both have it right.

Bink

Forums are terrific!
I wasn't trying to be humble...I was stating the facts!
Figuring out the IAC and RAF tables was very significant - I also remember when you persisted, on the Edit list, about IAC applying to ETC/ Vettes.

I'm just trying to give credit where credit is due. .................

Bink

Naaaaaaaaaaah......................RAF and IAC??

The MAF is your friend.

SideStep

tons of good info.....




F13, Sunday....