RICEETER

iTrader: (49)

my car is shifting to second gear immediately upon launch (leaving it in drive) AND its shifting out of first gear early.

my shift tables are apparently screwed up. i've been told that the computer was commanding the "quick" shift because of something to do with the speed density tune but havent found an answer as to why.

will some of you guys ask around (ask your tuners) and get back with me with some things i might be able to try?
thanks,
brent

Gilbert@Ace Racing

I would be surprised that this began to happen with out some sort of a change... hardare or software.

Can you tell us what if anything has been changed recently...

Usually a change in the gear ratio will create a stack shift like you are describing here. If the gears were changed, sometimes even the tires, then adjustments will need to be made in the appropriate tables.

Can you provide us with more info?

g

RICEETER

iTrader: (49)

i really dont have anymore info. nothing has been changed. i got my SD tune a couple of months ago and this just popped up and started happening to me a couple weeks ago. the ONLY thing that comes to mind is the fact that my tires are worn slick, but they are MT dr's and shouldnt be but about 1/2" shorter than stock. i dont think that little bit would change anything. other than that, nothing has changed

RICEETER

iTrader: (49)

anyone else?

Gilbert@Ace Racing

Sorry for not following this more closely for you.... been busy here at the shop.

The 1st thing to do is verify that indeed the shift in question is indeed being commanded early. If so it is a tuning issue.

"my car is shifting to second gear immediately upon launch (leaving it in drive) AND its shifting out of first gear early." [B]I just re-read that comment, can you explain please. Shifting out of 1st early and shifting into second gear immediately are the same thing.

kruthes1

iTrader: (2)

This same thing happened to my car. We went back with the M/A tune and all is well again.

98Z28CobraKiller

iTrader: (17)

So after you put the SD tune in, it drove fine for a month and then all of the sudden this started? Nothing else happened around the same time. The tune would not work for a month and then suddenly stop working correctly. Perhaps you have a bad sensor maybe bad wire that is laying on your exhaust or something.

RICEETER

iTrader: (49)

im sorry for the confusion. i leave it in D (3rd) all the time when racing because i always have and its always worked fine. now, what i meant to say was: sometimes when in launch, it immediately goes to second gear (i mean within 5-10 feet). OTHER times when i launch, it stays in first but shifts early to second (like 6200 when my shift points are set at 6650). i dont know how to tell if the computer is "commanding" the early shift. when we data logged a few passes, we saw that it was shifting way early.

performabuilt

iTrader: (25)

The data log is showing you what was comanded so you allready have that information.

Gilbert@Ace Racing

we saw that it was shifting way early.

Based on what information?

performabuilt

iTrader: (25)

I think hes saying that the place he has it set to shift and what the data logger Is showing about The actual comanded shift is different,
for instance set to shift at 6200 but the PCM comanding it at for example 3000.

RICEETER

iTrader: (49)

correct. it is tuned to shift at 6650rpm but we data logged a pass at the track on efilive and then come back and watched the pass on the computer. its logs everything your car does, for example a/f, shift points, mph, knock retard, etc. we watched the car shift out at 6200rpm

Gilbert@Ace Racing

If you could send me the EFI Live .bin files and a very detailed explanation of what takes place I will get with the Tuners next door and see what we can find out for you. I think there is some conflicting information in some of your shift tables. Not sure, but it is extremely unlikely that this is a internal hardware issue.

Let's see what that does for us! Get me those tables and log files. Contact info in my sig.