A4 tuning - surging on lockup with cam/boltons

[mrkrad]

Whats a good way to cure surging with a 112lsa 224 style cam.

Scenario: Flat or declined ground, lockup at 1000rpm (3.42 gears), car shudders when no or low throttle.

I need lockup for city driving mpg. The car shows no knock, no gear shifts (efilive 6.4.0), no nothing out of ordinary. Out of gear idle is 1000rpm (high?) and cold/warm starts are a bugger.

This behaviour is at all temps (trans/ect). I have a tci ssf 3500, ls1edit tuned (soon hptuners order placed!) and i need more gas mpg, unlocked i got 9mpg in 100% city driving.

I am not sure what idle in gear is, and im not sure if the IAC (stock TB) values are (what is nominal?).

My only guess is timing/air fuel in closed loop/low tps or idle rpm in gear is causing this shudder.

If i give it any gas to accelerate there is no problem. In third gear it is even more pronounced. I don't want to wreck the driveline with this shuddering. There are no codes being set, car drives great above 1600rpm absolutely no surging.

Please help me out, this is why i bought the software to nail driveability.

I'm posting another thread in the engine tuning section about why i need to have 1000idle rpm's with this cam.

any tips appreciated. or if its not possible then i guess i'll have to live with it or go unlocked driving around but that seems like it would punish the trans temps as it is.

[mrkrad]

bump i set commanded RPMS to 800rpm, in pn/in gear, yet when im letting the car cruise it seeks 1000-1200rpm, what do i need to change i did a .90% on throttle cracker didnt seem to make much difference. car still has the herkie-jerkies at 1000-1400rpm lockedup in 4th.

help a bro out. I do 90% city driving so its important.

[mrkrad]

im logging mass air flow of 1.67-1.75lb/min
idle air flow desired 1.087-1.106 lb/min
at 45mph 0% TPS (surging)
ignition 38-39 degrees
rpm ~1473
IAC steps /desired 88-92 (tracking well)
LTFT 1/2 (-0.8%/-0.8%)
map 5.7hg (note there is no such thing as PSI in our map sensors, its HG)

So my guess if the conversion of MAF lb/min and g/sec
was accurate is that the idle air flow desired is WAY OFF
what about the timing is that too much for 0%?

Problem: Surging at small grade,flat/downgrade from 900-1500rpm in 3rd or 4th locked up.

I'm gonna filter the data in excel in a bit but anyone know the formula to convert lb/min to g/sec ? i used an online calculator why does the mass air flow use a different measuring method?

[WS6snake-eater]

did you ever get these issues worked out?

[ladyredhawk]

Is it surging at around 1,500 rpms or so and maybe 40ish mph? If so go to the tcc tables and raise the lock up to 51 mph.

[Bill@HPTuners]

Is it surging at around 1,500 rpms or so and maybe 40ish mph? If so go to the tcc tables and raise the lock up to 51 mph.

im with you on this...thats what i did just made 3rd gear lock at like 255mph and 4th gear to not lock till after 50mph...then again i had 2.73 gears so yours will be slightly different...basically when it locks up see at what point when backing off of it it starts to buck and set your mph 2mph past that and your unlock points 1mph past it and you should feel no bucking look at it this way did you really think a 3500 stall and a cam was going to get you good gas mileage? Good luck :-X