davidb5303

I have a 5.3 with a 4L60E trans and the motor runs super but it doesnt have the "pep" it should when your going down the road and get in the gas. I think its in the trans tuning cause it doesnt really downshift even at 100% throttle. So just curious if there are certain percentage of throttle there telling trans to downshift or shift at? Hoping someone can fill me in so i can tall intelligently to the tuning guy. Or are there any good places in Northern Illinois that do this? Thanks

mrvedit

Yes, depending upon speed and throttle position the stock tune will obviously downshift.
For example, in the stock 2002 Camaro SS tune:
At 50% throttle it will downshift 3=>2 below 33 mph.
At 100% throttle it will downshift 3=>2 below 86 mph.

If your trans is not downshifting, you should start by using a scanner to confirm that the PCM is ready the throttle position correctly via the TPS.

davidb5303

OK thanks...I will have the engine tune guy check that...its a 5.3 and 4L60E that i put in a 76 Trans Am. I was just hoping for info so I could ask him smart questions or tell him "these are the parameters i want it set to" kind of thing.

davidb5303

is there an inexpensive scan tool that i can use to reap the TPS?

mrvedit

I would expect that the scan tools you can rent for free from auto stores will display the TPS %. While I use HP Tuners, my cheap Harbor Freight scanner also displays TPS %.

davidb5303

I am sure this is a loaded question but... is there a generic set of parameters that I can say"this is what I want"? For my trans to do in my 5.3 swap in my 76 TA?

davidb5303

And which "inexpensive" harbor freight diagnostic tool do you use!