rolling idle

[jfclubby]

Hi everyone, Yesterday i installed a new comp cam into my clubsport. I got the car idling good and have done a quick RAFIG/RAFPN (will be doing a proper RAFIG/RAFPN in the morning when it is dead cold) and done about 1 hours worth of auto ve, The thing that has me stumped is that when you cruise at about 60km/hr and get off the throttle it seems to hang around the 1500-1800RPM mark with no throttle at all. untill you get on the brakes and slow down then it comes down to normal. I'm wondering if this could be related to desired airflow being set to high so when you get of the throttle it's got too much air flow, Or could it be that the throttle cracker and follower tables need looking at. I have posted a copy of my current tune.
The details of the engine can be seen in my sig.

Any help would be great as this is my first cam tune, please look over what i have done so far, all sugestions would be much appreciated.:cheers:

Regards James

[jfclubby]

I do think it is cracker/folower related after reding through some info on this forum but am unsure of how i go about setting these up properly, Could someone please explain the best way to nut these out.:cheers:

Regards James.

[Tordne]

The desire airflow will make the cars revs hang high or dip and almost stall. Once you have doe the RAFIG etc this should be resolved and pretty stable. The Throttle Cracker adds airflow based on speed, where as the Throttle Follower ass airflow based on change in throttle position.

What you describe sounds most likely to be desired airflow and throttle cracker. If you were to rev your car when stationary and the throttle hangs and comes back to idle too fast or slow that is throttle follower.

Hope that helps.

[jfclubby]

Hi, thankyou for your reply Andrew, when you give the car a rev when stationary it comes back to normal fairly quick. The other thing that i've noticed is that when you take it out of gear and into park the idle goes up to 1200rpm for a second then goes to normal is there a table that controls airflow on the comand of a gear selection.:cheers:

Will do a proper RAFIG in the morning from dead cold to get the whole table right.

Regards James.

[Sid447]

James,

Why not try the 2003 HSVGTS-A4 tune that is available on holdencrazy.com?
Flash it in as is, with no changes and see.

The desired airflow in your tune is pretty radical. I don't think you need such high values.
Try the following tables pasted from the '03 GTS-A4:-
B4301, B4302 & B4307

This kind of thing frustrated me too, and it took about two years to finally get it sorted out the way I like it (i.e. no assistance from the PCM with the revs floating around 1100rpm for a few seconds when I came to a stop and also "floating" between gear changes etc). Also the Throttle Follower wasn't allowing the IAC to return to the normal idle range fast enough.
Thankfully I'm there though now, or around 95% anyway!

The only thing I'd like is for it to react (we're talking M6 here) like the BMW's do when you let the clutch out without touching the throttle. If anyone has driven and noticed how the Beemers do this they will understand.

[vxchev8]

Why is your {B4311} "Throttle Cracker Activate Speed" set at 113 :secret:

[TAQuickness]

If the stationary idle is good, and the transitions back to idle are good, with the exception of the idle hanging at certain RPM ranges I would suspect the TC to be the culprit.

[jfclubby]

Hi vxchev8, I looked at that after my initial post thats why I thought its cracker related, After noticing that it was set to 113 it made me see that even before the cam was changed it would not have been working like it should have. I have set it to 5kmh activate and 2kmh deactivate and also droped the grams/sec down from what was a very high. I'm about to do the desired airflow in gear now and i will see what happens then log throttle cracker, throttle folower, Maf, rpm, vss, to see just what is going on with the cracker and follower and how it's applying the additional air flow. :cheers:

Not 100% sure how the cracker/folower features need to be set up but i supose one way to learn is to make some changes and see what happens, Can only get better or worse:hihi:

Regards James.

[jfclubby]

Done my RAFIG and during that the pcm threw a code
P0121 " throttle position sensor 1 performance "

What could that be from?:shock:

[jfclubby]

It's ok I found the p0121 code problem, ajusted the c3907 tps v's rpm table to zero in the 800-1200rpm cells:)

Thought my desired air flow in gear was too high so i lowered it to see what happens...... no good it wont idle so i changed it back to how it was after the RAFIG.

Just wondering if these numbers are kind of normal with this size camshaft.

Regards James.