Zombie

iTrader: (2)

I'm lacking some understanding when it comes to getting the corvette electronic throttle control to do what I need it to.

My current issue is a 2002 Z06. I can get the car to idle exactly how I want as long as the car is not moving. As soon as it moves the idle goes to hell, surges, stalls, idles low 400 rpms etc. The car has an alum fly wheel, 232/238/114 cam, ported heads, etc. Makes great power (466rwhp) but drivability is the problem.

I've tried all the basic stuff, eliminate the throttle cracker, change the decay time, lower ve, change base running a/f, etc. I have a temp work around for the guy right now which was to take the decay and set it to 0, this made the car at least drivable, but it's still nowhere near as good as I feel it should be.

I've been tuning LS1's for quite a while now and this one really is baffling me. I can get a F-body to idle great by simply making the IAC counts match desired and setting the Base running airflow correctly. This vette is kicking my butt though.

Someone want to walk me through the basics of making a cammed vette idle correctly, what i've done on previos vettes hasn't worked so far.

Gman2002Z06

Are you using HP Tuners...If so, I can shoot you a copy of my .bin file...Otherwise, I will send you an Excel file with the parameters...

Don't have the ported heads, but other than that, mods are very similiar...My car idles extremely well at all times...

Send me an e-mail address to send the file too and we'll see if any of my numbers help you...

Peace...Gman

Ikestaa

Gman,
Would you mine sharing your .bin file with me? (sorry to hijack)

Zombie

iTrader: (2)

i'm looking for some more insite as to why this car is doing this. The tune that was sent did the same thing.

I've never had trouble getting a car to idle before. I'm wondering if it's something besides the tune.

Billiumss

iTrader: (11)

Your idle tables are out of wack.

IF your RAF is correct then your Throttle Cracker table is too low. Think about it for a sec, when you start to move 1-2 MPH, your Throttle Cracker table kicks in and "Cracks" the throttle blade open a tad and bumps your RPMs up 100-200 rpms.

Put your stock Throttle Cracker table back in and just add 5% to the whole table, see how that does for a few hot/cold starts. If it helps some then you have to fine tune it and it's kinda trial and error. Just add to the MPH that you are having problems with.

Hope this makes sense...

Bill

Zombie

iTrader: (2)

I've tride disabling the throttle cracker and also reducing it, but I haven't tried addint to it yet. Wouldn't zeroing the TC table or changing the enable speeds change everything? When I did that the car still had the same issue, great idle when not moving, hunting/surging/stalling when coasting with the clutch in. It finds idle once mph = 0 though.

Checkmate

iTrader: (2)

Disabling the throttle cracker table will only make it worse, don't do that.

z06ufgrad2002

I've got his exact same problem. Idle hunts while coasting and then is steady as soon as the car stops moving. I would LOVE to know what the fix is for this.

Zombie

iTrader: (2)

Yup, figured that one out fast.

LTIT seems to be off by -.20lbs/min. STIT is 0 when driving or parked. Base running a/f is 1.20lbs/min desired is around 1.0-1.05lbs/min so I have to lower the BRAF a little it looks like.

Hopefully i'll be able to tweak on the car a little later on tonight or tomorrow. It's not my car so I don't always have access to it.

z06ufgrad2002

Please let us know if you find the cure. As I have been dealing with this intermitant issue for almost two years and would really like to get it fixed.

Zombie

iTrader: (2)

I increased the throttle cracker table by about 30% and that solved most of the issues. It still has some parking lot speed issues, but the car is drivable for now. I'll have to work on the less than 5 mph issues.