99whitews6

iTrader: (2)

When I slow down to a stop I get some decent surging. The surging stops as soon as I get below a certain MPH(assuming It changes over to idle characteristics). Any ideas? Is it still the RAF?

Bink

Idle routines start at zero MPH and after a time delay.
If surge occurs below Throttle cracker Disable MPH and zero mph then maybe RAF (LTIT could be contributing factor also...as Base Idle airflow). Scan it.

99whitews6

iTrader: (2)

I looked at a couple of logs and when slowing down, once the TPS hits 0, it surges when coasting to a stop from approx 18 all the way down to 3 MPH. As soon as it hits below 3 MPH the rpms get dead steady at 900 rpms.

Haans249

iTrader: (24)

Try checking all of your throttle cracker and follower airflow and decay tables...those will square you away =D You should set all the multipliers to 1.0, so then you can fine tune the airflow tables easier without having to worry about the stupid multiplier.

Best Regards,
Adrian

99whitews6

iTrader: (2)

THanks, what size increments would you suggest going with? Should I assume that I need to add to it to begin with?

Haans249

iTrader: (24)

Log your cracker and follower PID's and see where you need to go =D Log, Log, Log!

Best Regards,
Adrian

silverTA2002

iTrader: (1)

Throttle cracker crap makes my car do it. I tried tuning the throttle cracker, to no avail.

Finally, I just disabled it under 10mph, and decreased it by 10% above 10mph.

It hunts a little now, until I get below 10mph, then it's perfect.

One time, I even disabled it completely under 30mph. Most of the time, it'd find idle perfectly, but some times, the rpms would drop too fast, and it would dip to 400rpm, so that didn't work either.

Honestly, I just gave up after I got it close.

GuitsBoy

iTrader: (4)

is it surging? Or is it the dreaded low-rpm/low-load cambucking?

99whitews6

iTrader: (2)

Its surging. RPMS show about a 500 rpm wave then go dead flat.

Doc

iTrader: (9)

If your tps is below 1 then you are in the idle in gear spark table. I had a surge after the h/c/i . Like around 45, 35 coasting- I would get a bucking, surging. Logged the spark, tried cracker, follower to no avail. Looking at the idle in gear spark revealed it switching back and forth between cells (.12, .13g) that would not be used with the stock h/c. I just smoothed out the cells in the surging areas.

Haans249

iTrader: (24)

That is a good suggestion, check your base idle spark tables, and adjust your base spark timing (under 2000 rpm range) and see if it needs to go up or down. My particular setup was extremely sensitive to idle spark changes, going from 21-23 made my car stall on start up. So, I would suggest starting with 5 degree increments at first to see if you need to go up or down, then start from where you were before and go +/- by 1 to .5 degree until it settles down.

best Regards,
Adrian

99whitews6

iTrader: (2)

Ok, if a 2 degree increment made it stall, why would I want to start with a 5 degree increment? Just looking for some reasoning!

Thanks

Doc

iTrader: (9)

Log Cylinder air and spark adv. During the deacceleration periods I could see a squiggle spark adv. as the cyl air was "strattling" some rpm vs. cyl air cells. For example at say 12-1300 rpm btw .10-.12 air there are no specific cells for the pcm to go to so it just goes back and forth btwn 12 and 1400 rpm in which the table went from 28* to 35* thus the bucking on deaccle. As soon as you go above 1%tps you go back to the H.O. spark table. Look at those "hard transition" areas and smooth them out. The pcm will only do what it is told.

99whitews6

iTrader: (2)

Sounds good. I am still using same timing values for both high and low octane tables. Will this screw anything up if I leave it this way?

Thanks

GuitsBoy

iTrader: (4)

You wont hurt anything, but you really should be running more timing unless you have a tiny cam in that motor. A bigger cam with more overlap will have a sloppy charge that wont burn as rapidly, so you run a little more timing down low to compensate. I dont know about big cubes, but for my cam and most others in the mid 23x range, they like around 28* timing at idle, and up from there. Your compression also plays a role in this.

99whitews6

iTrader: (2)

I copied the high octane over to the low octane. Other than that I really have not messed with the values. I plan to start tuning timing as soon as I get this surging figured out. If throttle cracker/follower airflow doesnt fix it then I will go to the base idle spark and then start messing with the regular timing table.

SSpdDmon

iTrader: (10)

Any chance you can post your high octane, base spark (park/neutral) and base spark (in gear) timing tables? I've got 2 friends that just went with TSP torquers ('99 and '00 f-bodies - so thier spark tables are a little different than what I'm used to seeing) and would like to see where you've got your numbers.

jimmyblue

iTrader: (11)

https://ls1tech.com/forums/pcm-diagnostics-tuning/456413-weirdness-throttle-cracker-stalling-fix.html

GuitsBoy

iTrader: (4)

Ill upload my current tables, Both base spark tables are identicle, and theyre merely resamples from the high octane anyway.

I have to warn you that these tables are very conservative since im tracking down some low rpm KR that might be false. Im also running 10.9:1 compression (8.25 DCR) on 93 octane. Im currently running in open loop - MAF mode. Still not completely away from the low rpm bucking though.

SSpdDmon

iTrader: (10)

Thanks! Now I just have to convert it for EFILive.