1-2 shift way off.

this is a 99 gtp L67 swapped into an 86 fiero gt.
tires are 245/40/18s
I have done the conversion from 225/60/16 in the speedometer tab.


anyway heres the strange issue.
in first, once the car gets up to about 37-38mph and 4600-4800rpms or so (i think my speedo is out)

its like the tranny disengages and the rpms take off under no load.
it will then bounce the limiter a few times, and then quite snappily grab second.

I have tried everything i can think of with torque management, changing mph shift points up and down, rpm shift points up and down, nothing seems to change this issue. always the same thing, at the same rpm.

Tranny fluid has been checked.

today I confirmed without doubt that its not clutches slipping, as i tested for a few hours straight, the shift to second is always fairly crisp, but
it seems to start to early, and take a long time to happen.
also never smells like burning clutch.



Any help would be greatly appreciated!

heres a little scan of it if it helps.

Im having trouble uploading my tune....but it wouldnt matter anyway, as it still does this with completely stock transmission tuning.
(which makes me think its something to do with the speedo settings)

bump.... anyone?

nobody has any clues? :(

Post your stock & latest tune files. Also list all the mods to the engine & trans. Is the stock reluctor wheel still in the trans? Is the trans from a 1999 GTP as well?

Why is your IAT at -38*F all the time?

Russ Kemp

I havent hooked up the ambient air sensor yet.

Engine mods are: XP hot cam, 105 springs, new timing chain and tensioner, MSD plug wires, ZZP S2 intercooler, zzp fuel rails, 42lb injectors, autolite plugs, 3.0" pulley, K&N air filter, ported header/Plog, custom 3 inch exhaust.
trans is exactly how it came out of the 99 gtp.

i was having issues getting a tune to upload but i will try to do it again.



Ok. heres stock file pulled from the 99 gtp engine,
and a file with my basic engine tuning set up, and before i started playing around with the speedo tab to try and fix this issue.

My tires are 245/40/18
stock gtp tires are 225/60/16

Try this trans tune. Note that a 245/40/18 tire is 1" shorter than stock.

Are you getting any codes other than the IAT sensor codes?

Russ Kemp

no codes.
thank you for helpin russ.
unfortunately my 25 year old fiero axle on the drivers side wasnt up to the abuse and self destructed today. so ill have to wait till i can get a nice performance axle sent my way before i can test it out :(

sorry to hear about your luck, these kind of problems suck. Keep us updated.