Bill Bowling

iTrader: (6)

Still getting the bucking around 1500 at 0% TP. I am running SD mode. Bucking has been there since the cam was installed (before and after SD). VE Table is within 2%. I am also running EFILive OS 3. I have tried: Increasing Spark; decreasing spark; increasing the AFR. My idle cells are right on. Below is the last log in the bucking are. MAP is around 50kpa.

Car runs great except for this bucking which is getting to be a pain .

Can anyone help?
Bucking Area 11-03-05
..Frame ..Time GM.KR SAE.ECT SAE.IAT SAE.MAP SAE.RPM SAE.SPARKADV SAE.VSS GM.TP GM.AFR GM.DYNAIR CALC.AFR_LC12

754 13:00.1 0 172 73 53 1621 26 53 0.4 14.63 23.24 14.55
755 13:00.3 0 172 73 49 1596 26 53 0.4 14.63 21.36 14.56
756 13:00.5 0 172 73 48 1575 26 53 0.4 14.63 21.15 14.58
757 13:00.7 0 172 73 48 1615 25.5 53 0.4 14.63 21.51 14.46
758 13:00.8 0 172 73 48 1573 26 53 0.4 14.63 19.78 14.34
759 13:01.0 0 172 73 48 1622 26 53 0.4 14.63 21.2 14.51
760 13:01.2 0 172 73 47 1555 26 52 0.4 14.63 20.09 14.48
761 13:01.4 0 172 73 48 1595 26 53 0.4 14.63 20.41 14.77
762 13:01.5 0 172 73 46 1592 26 52 0.4 14.63 20.29 15.15
763 13:01.7 0 172 73 47 1575 26 52 0.4 14.63 19.77 14.77
764 13:01.9 0 172 73 47 1544 26 52 0.4 14.63 19.11 14.74
765 13:02.1 0 172 73 47 1543 26.5 52 0.4 14.63 18.98 14.34
766 13:02.2 0 172 73 47 1498 26.5 51 0.4 14.63 18.95 14.86
767 13:02.4 0 172 73 48 1526 26 50 0.4 14.63 19.44 15.18
768 13:02.6 0 172 73 48 1496 26.5 50 0.4 14.63 18.98 14.84
769 13:02.8 0 172 73 48 1471 26.5 49 0.4 14.63 18.78 14.87
770 13:02.9 0 172 73 49 1461 26.5 48 0.4 14.63 18.78 14.64
771 13:03.1 0 172 73 49 1441 26.5 47 0.4 14.63 19.09 14.17
772 13:03.3 0 172 73 49 1421 26.5 47 0.4 14.63 18.53 14.01
773 13:03.5 0 172 73 49 1412 26.5 45 0.4 14.63 18.65 14.11

WS6FirebirdTA00

iTrader: (33)

same thing for me man, the thing that has helped me the most is proportional fuel. the o2s were switching so slow it was making the fueling odd. since then a lot of bucking has gone away. still have some though. main things i found with mine were idle airflows but mostly fueling. how is it if you throw the car in open loop when its hot?

Bill Bowling

iTrader: (6)

I am running SD all the time and use my LC-1 WB for any changes.

Bill

ninobrn99

iTrader: (8)

ttt...hopefully you guys get it figured out so i dont run across the same issues.

WS6FirebirdTA00

iTrader: (33)

i just seem to notice it most when the o2s switch bad or i get in that part of the ve that wont lean out on me. doesnt seem to do it when the car is cold either. i did notice that my idle airflow values are way off depending on the oil temp. maybe that has something to do with it for me, but i dont know. but it has gotten a lot better since i lowered the proportional fuel. bill, what injectors are you running?

Bill Bowling

iTrader: (6)

I have the stock injectors.

Bill

5.3litre

iTrader: (6)

i started a thread about bucking issues a few days back and it seems that no one has a cure for this issue..i know what you guys are going through..it sucks when the car starts shaking like ****..just pisses you off..

technical

I noticed that your min TPS voltage is 0.4 just like mine. I changed a parameter called "min tps voltage for idle" to use 0.5 instead of 0.0 to help fix some erratic stalling behavior at lower speeds. You can give that a shot...

WS6FirebirdTA00

iTrader: (33)

is there any way to graph o2 oscillation in efi? with headers and stock injectors i had to change some settings still. some cars can go without having it messed with but mine needed it.

WS6FirebirdTA00

iTrader: (33)

what issues did you experience with the tps voltage issues?

Bill Bowling

iTrader: (6)

I changed that one months ago. Thanks.

Bill

ninobrn99

iTrader: (8)

Bill, what does your injector duty cycles look like?? stock injectors should be maxed or close to shouldnt they??

Patrick G

iTrader: (14)

A lot of the bucking can be a result of the IAC motor fighting with the PCM. Try unplugging the IAC motor (after the car's warmed up), then see if the bucking gets better (or worse). If it changes, then you have a pretty good indicator that additional work needs to be done with the IAC effective area table.

technical

After the heads/cam swap and the initial dyno tune, the car would like to stall while coasting at low speeds (M6) especially while I was turning into my driveway. Actually the rpms would get very erratic and sometimes stall. I had bumped the minimum tps voltage setting and I also modified the over and under spark correction tables so they didn't swing the timing so far. I figured the PCM didn't realize the car was basically idling considering the TPS voltage was at .4 and not 0. Other than that the car idled just fine and I had no bucking while cruising. Just the intermittent stalling/surging issue while coming to a stop and/or turning.

GuitsBoy

iTrader: (4)

WS6FirebirdTA00 - when you say your lowered proportional fueling, what exactly did you lower?

Bill Bowling

iTrader: (6)

I am not sure. I have not logged them lately. I will have to look at them again.

Bill

WS6FirebirdTA00

iTrader: (33)

the closed loop prop fuel, it has values in the 100's. i droped them down becuase my oscillation was very slow and hanging. my values are extremely low now, but bucking has gone away a lot. between that and fixing the throttle cracker table. if you need a hand with seeing how yours is let me know. just get a driving scan at constant throttle and scan o2s to see how the oscillate.

Checkmate

iTrader: (2)

What did you 'fix' with the throttle cracker table?

I've been tuning my ve table the last few days in OL/sd mode, I have very minimal surging at 1500 rpm and some very random surging while slowing down between 1000-1900rpm. Very little left but I'd like to get it better if possible.
thanks for any advice

Silverhawk_02TA

I definitely found that IAC operations were a big part of my cam surge. Through tuning spark and VE and all that good stuff, I was able to keep the surge to under 1200 rpm. Once I nailed the IAC vs Effective Area and RAF tables, it now only starts to surge at 900 rpm, and then only in 1st or 2nd gear. I can cruise all day in 6th at 800 rpm with no surging. I have the same cam you do, so you should be able to get similar results.

Definitely make sure your idle stuff is dead on, and also the idle proportional fueling like WS6FirebirdTA00 mentioned.

WS6FirebirdTA00

iTrader: (33)

i lowered some of the values, some of the stock values in my table were damn high, over 2 g/sec around the bucking range. now the majority of the table, all my values that were 1.1 and higher, are set to 0.9 now. im not sure how much this helped out the bucking but i think it may have helped slightly. im still trying to work on it. im also trying to fix warm start idle, im about ready to ditch the damn o2s though and go open loop. these o2s are little bitches sometimes