1MeanZ

iTrader: (9)

Guys, this is a very simple problem to explain. $6E, stick shift car, mild cam. When i'm decelerating in gear my IAC steps slowly go down to 0. Then when I push the clutch in before I come to a stop, the IAC steps are still at 0 and the car tries to stall and many times does before it catches itself. This is the only other drivability issue i have left and I can not make it go away! Any help from you guys would be greatly appreciated.

gta324

What are your IAC steps at idle in (D) and (P)?

You could also try raising your SA in the area where it stalls, but I havens seen your bn or scan so its hard to tell. Also DFCO settings maybe needs to be adjusted.

/N.

1MeanZ

iTrader: (9)

it is a manual trans car. In neutral it idles at about 24 steps at 875rpm.

pandin

If the IAC is removing steps, it is trying to lower the Idle speed.

When the engine gets below a set rpm the stall saver kicks in.This is set at Location 24-27 "Stall Saver Spark Enable RPM Threshold 1-3" Each threshold changes the timing (adds more I think).

The last is "Stall Saver Spark Disable RPM Threshold", this one removes the stall saver spark change.

An observation, something adds more fuel during a stall, so if you are "rich stalling". the engine just gets drowned even more.

I have mine set at 1-550 2- 450 and 3-350 disable at 300

Also check the 0 values in Maf settings raising these to the normal idle Grs/sec will keep the ECM from trying to make a big fuel change when the rpms drop.

1MeanZ

iTrader: (9)

Thanks for the info. I'm going to look at my tune tonight and try a few things. I have slightly modified some of those values, I'll see what I can come up with. Thanks for the suggestions.

1MeanZ

iTrader: (9)

I changed the stall saver rpms and the stall saver enable rpms to various settings. I even had the stall saver set at 700-600-550 with no luck. by watching my wideband it does not look like the car is drowning or rich stalling. The only thing I can do to get the car to stop stalling is to change the value of "enable IAC PID if MPH is GT" I can set that to various settings. if I max it out at 78 the car stalls like it has been. If I have it at 35, the car stalls on slow speed turns around town. I set it at 15 and the car acted the best it has since I started. I actually couldn't get it to stall.

Previously when I've had the "enable IAC PID of MPH is GT" above 1.88 the car would hang on a high idle when I pushed the clutch in. It would hang at 1500-2200rpm until I come to a stop. It didnt do it on my test drives, we'll see how it does over the next day or two on my commutes to work.

If you guys have any other suggestions I'm all ears. Even though the car didn't act up, I'm still not sure if this is the "right" way to fix it or not. At this point, this is the only thing the car does that is not satisfactory. It gets 22mph with mixed driving, and idles, runs and drives near stock. I'm very happy with my progress so far, I just need to put this last issue to bed.

RBob

iTrader: (1)

I would tend toward something in the calibration is not set up correctly. There is no reason for the IAC to step to 0 while decel'ing if the engine idles at 24 steps.

Maybe throttle follower or minimum idle steps is incorrect. IAC is sticky and undershooting?

RBob.

1MeanZ

iTrader: (9)

my IAC steps added to T/F in drive is set at 5. Not sure which parameter you're referring to about minimum idle steps, the keep engine alive steps is 40. I thought for a time I had a bad IAC, so I put a new one in and set the minimum idle screw the right way by doing a search on here. It didnt help my problem, if anything it made it a bit worse.

pandin

Here is a $6E stall on a stock 350 at Idle.

"An observation, something adds more fuel during a stall, so if you are "rich stalling". the engine just gets drowned even more.

I have mine set at 1-550 2- 450 and 3-350 disable at 300"

Notice as rpms drop lv8 rises and this causes a rise in the fuel (IBPW), but the big jump in fuel (9.6 ms) is right after. (#234 sec is completely missing)

IAC and LV8 run up together, but Spark (47*) and O2 lag way behind.

O2 mv are low due to O2 swings set low (my tune).

RBob

iTrader: (1)

To be honest the conditions and the stall are puzzling. Is the park/neutal input to the ECM open? This tells the ECM that it is in drive, which is standard for a stick tranny.

There is also the TCC bit (flag) along with an IAC parameter flag for stick. Note the TF steps.

RBob.

tequilaboy

Check your warm park IAC vs coolant temp table and be sure that the manual flag at LC579 is set. You may also want to increase the offset at LC57A to get more counts when rolling above the PID maximum speed.

;------------------------------------------
; WARM PARK POSIT. vs COOLANT
;
;
; ARG = STEPS
;------------------------------------------
LC587: FCB 8 ; 8 + 1 LINES IN TABLE
;
; STEPS Deg c COOL
;------------------------------
LC588 FCB 125 ; 125 -40
LC589 FCB 100 ; 100 -16
LC58A FCB 75 ; 75 8
LC58B FCB 50 ; 50 32
LC58C FCB 25 ; 25 56
LC58D FCB 10 ; 10 80
LC58E FCB 5 ; 5 104
LC58F FCB 5 ; 5 128
LC590 FCB 5 ; 5 152
;------------------------------------------

Closed loop idle PID control can also be extended for use at speeds as high as about 15 mph or so by increasing LC545 to maintain the target rpm while rolling in gear. I use this as sort of a low speed cruise control for rolling at idle in 2nd at 8 mph, or 3rd at 12 mph @ 800 rpm with my 3.73 and 4+3 gearing.



;------------------------------
; PID ENABLE CONDITIONS
;------------------------------
LC543 FCB 3 ; 1%, ENAB T/F IF TPS GT THRESH%
LC544 FCB 0 ; 0, DONT STORE NEW TPS IF ID DIFF VAL < THRESH
LC545 FCB 6 ; 1.8 MPH/3.2, ENAB IAC PID IF Vss > THRESH
LC546 FCB 4 ; 50 RPM/12.5. MIN RPM UNDERSPEED ERR TO ENABLE
; PID DURING TRANSISION DELAY
;----------------------------------------------


;------------------------------
; MANUAL PARAMS
;------------------------------
LC579 FCB 0 ; FLAG = 1 IF MANUAL, else = 0 <----<<<<<
LC57A FCB 5 ; 5 STEPS ADDTED TO T/F IN DRIVE & x MPH
; MPH = LC545, 1.8 MPH.

1MeanZ

iTrader: (9)

I'm going to have to go slow here and take this one post at a time to make sure I understand, and communicate clearly.

I have the park neutral switch from the old automatic shifter wired up to the clutch switch. The clutch has to be depressed to start the car or to even open the hatch.

I have the manual transmission flag checked. (Hex 0014 Bit 0 if I right click and look at the xdf info) I'm using the 6Exdf from Moates' website. I have tried a few times and unsuccessfully been able to add items to my xdf. You guys post the location in the code and I have not yet been able to get those to come up by modifying my xdf to read them. I'm using tunerpro, and when I try to make a new xdf, it doesn't seem to come out correctly. I'm going to keep trying to find the items in code you guys are talking about....

RBob

iTrader: (1)

With an auto car there is another prk/neut switch. It tells the ECM whether the shifter is in park/neutral, which is ground. Then opens the switch when in any drive position. Seeing the TKO I figured it may have had an auto and you may have tied that wire to ground. That would tell the ECM that the trans is in park/neutral all of the time.

Which is the opposite of what is required with a stick tranny. Wire color is typcially orange with a black stripe. And would be found in the shifter area. For a stick tranny just leave the wire open.

RBob.

pandin

Make your changes in TunerPro (make sure to "apply" all changes) then do a "save as" and rename (I use a date "year month day" type name, so you don't over write the old one.

When using TunerPro, it is a good idea to do a "save as" first, bin or XDF. That way all the edits are made to the new file not the old.

1MeanZ

iTrader: (9)

Rbob, whats your address so I can send you flowers? LOL I looked in the tech articles section at the auto trans shifter wiring and it is the orange and black stripe. I had it grounded to the factory ground wire just like the car was in park neutral all the time. I unhooked the wire and taped it up and drove the car. It really did make a difference. My stalling has went away. When I let off the throttle to coast, I can feel the IAC closing, and the car really engine brakes quite a bit once the IAC is closed. Then I quickly depress the clutch and before the engine would just stall, it now idles down and catches itself very nicely. Just as the engine drops below my target idle speed, it jumps back up a few hundred rpm, which is probably the stall saver kicking in? I may make a few tweaks to try to smooth this out a bit but I'm very happy that it does not stall anymore. The car has 17x9.5 rims up front, and when you lose your power steering mid turn, it takes a strong arm to continue to make the car turn!

The car also feels like it pulls out a little better. The car has very light weight forged Mahle pistons, forged rods and a knife edged and polished Callies crank along with a 15lb LB9 flywheel. My point is that the rotating assembly is extremely light as far as street combinations go. Combine this with my RAM powergrip clutch that is very grabby, and it makes it difficult to pull out. As I let the clutch out and the LV8 increases, the AFR would go way rich and the engine would try to stall before. Now it seems much less sensitive to that, I dont understand why that is yet. I understand that I'm being very picky, but I feel that it is important to get the car to drive as perfect as I can, especially when the tools are at my fingertips and all it takes is me to put forth the effort.

Pandin, your suggestions are next on my list. I'm continuing to review your posts and continue to try to successfully modify my xdf. Thanks for the PM, I'll be responding with my results shortly.