slowing down surging

[oztracktuning]

I have made good progress tuning my car - in many areas its heaps better. This is just one bug that is annoying me.

Here is a screen shot of the log.

It happens when i slow down top go up my driveway. Initially surging that threatens to get worst until i put my foot on the brake. Then it threatens again when on and off the throttle in the garage. My driveway is a slight slope.

http://www.oztrack.com/clubsport/slowingdownsurging.JPG

Steve

[eboggs_jkvl]

Engine off
Use the set screw on TB and raise your TB air flow about 3/4 of a turn.
Unplug the TP sensor
Turn on the Ignition but don't start, wait 5 seconds.
Turn off ignition and reconnect TP sensor.
See if that helps.

Elmer

[oztracktuning]

I already have the TB screw adjusted quite a way out. It is showing quite a high voltage (from memory its 0.76V). I dont know if this matters with the EFI live Custom OS3.

I was considering moving the TB screw back to the stock position and drilling the buterfly. I dont like how the car seems to a rapid boost in throttle the moment i move the throttle a zillionth of a %. I had the theory that a more open butterfly initially may have created this??? Maybe closing it will give me less rapid near 0% response and the drilling may help me get the right amount of air. I am interested in thoughts people may have.

[GMPX]

I am sure the drilling T/B has been covered over at LS1Tech a miilion times. The company that fitted my cam and larger T/B drilled it for me before I picked it up for tuning so I don't know what it would be like without it. I know that alot of tuners out here still do it, I don't know if that's a Lemming factor or it's just something that must be done.

Also, B5935 & B5936, these are set way to high for a cammed motor, drop the numbers by at least 70% assuming they are still at the stock 10degrees mark.

Cheers,
Ross

[eboggs_jkvl]

The ignition thing will reset your TP back to .4 and it will start there as "closed" and in idle. Drilling it does the same thing as the set screw. I also had to replace my IAC valve to get it settled down.


E:)

[TAQuickness]

Had a hell of a time with my idle. if you can, set all your idle tables back to stock, get your set screw a bit closer to stock, then log the RAFIG to get desired air flow straight. Then tweak your throttle follower table a bit.

Not sure with your cam, but I would suspect you could get away with most of the idle tables stock. Mine is 23x/34x on 115. I had to also tweak my start up air, and idle spark tables a hair to nail it down.

[Black02SS]

Had a hell of a time with my idle. if you can, set all your idle tables back to stock, get your set screw a bit closer to stock, then log the RAGIG to get desired air flow straight. Then tweak your throttle follower table a bit.

Not sure with your cam, but I would suspect you could get away with most of the idle tables stock. Mine is 23x/34x on 115. I had to also tweak my start up air, and idle spark tables a hair to nail it down.
But ya finally go it!
:banana:

[oztracktuning]

So the opinion is that i need more air through the TB not anything to do with air settings in my tune??

I can try this - i just wanted to see if there was any informed solution for my problem, rather than just trying one thing at a time.

[eboggs_jkvl]

OK, bottom line, I went from an LS1 to an LS6 engine. THe LS6 dropped the CR to 9.0 and that may be playing with my "fine tuning" issues. I surged like crazy. I replaced the IAC valve and that helped a lot. Playing with throttle follower helped but it made the car go into "Cruise control" effect. I reset the idle to a higher number. I raised the IAC position from 40C & up to 8.6. The idle air in gear from 60C and up to 8.6. I hit the VE table. I hit the high octane table. I edited the airflow decay. It all helped a little but it STILL surged.

Finally, I looked around and found a tune for an LS6 vette on the internet. I edited every table I had and matched the LS6 tune. Idle went to rock solid. I tweaked a few things and I'm expecting to do an autotune this week to fine tune the whole thing.

So, surely there is someone somewhere that has gotten the tune correct and has a setup like yours. It is a matter of locating it and working with the information.

The guys on here are the tuners. I just read pretty good and try to follow instructions.

Have you tried to run the autotune? Might that be your solution too?

Elmer

[Tordne]

Ok, I see you are in Australia so we at least have the same sort of car (I assume).

The first thing I'll ask is: Is your current tune based on an 04 GTS by chance?

[oztracktuning]

yes lots of its settings are GTS maybe 03

[oztracktuning]

The hunting at no throttle coast seems to have improved a bit from a combination of changes. But i had it stall tonight as i entered my garage up the driveway and when i have looked at the log the IAC steps drop to zero a few seconds before it stalled and was in the 20 area as i coasted down the road before driving up my driveway. What does too low an IAC step count indicate in terms of my TB body drilling/butterfly position and also in terms of my idle air settings? Any suggestions or is the best suggestion still the same - let the car get more air??