If this is dissabled in the ecm does it effect any other functions the ecm does other than limiting top speed of the car? Does it effect tc lock up or anything else?

Steve

 

Thats how the TC locks up. I dont know offhand what else it affects.

 

I guess I should have told you that the car in question is a 91RS and it won't go over 100 to 110 mph as the ecm shuts the fuel off.

Steve

 

The VSS limits at 115 and affects tc lock-up. It probably will cause permenant damage if you disable it completely. If you make it with an on/off switch and just turn the VSS off when you want to go 115+, and turn it back on afterwards you should have no trouble.

 

Thanks for the info I'll have to find the correct wires and splice away. I have a switch bank that I installed where the ash try used to be and have two extra switches out of four that are not being used. One for the tc lock-up and the other for the fan. Looks like the vss is next.

Steve

 

I'm thinking you're gonna have problems of some sort... not just sure what kind though but the electronic speedo plugs into the VSS and you might have some problems with the speedo! Maybe not! *Shrug*

 

Is there any way to change the speed limiter in the ecm to a higher speed setting. I will be swapping the 305 for a350 in the near future and don't want to be limited on top end runs. I know I'll have to burn a new prom for the 350 so I just want to be clear on what to do when the time comes.

Steve

 

VSS is also used in conjuction with the EGR, purge valve, air fuel mixture, and I think it also works with the IAC in some way for the idle speed. You can find all that info in a Helms manual.

 

I find all that very interesting... I've heard that before about how it works with all that other stuff!! However, my VSS does NOT work right now and my car runs just as did before.... the only thing that happened was my speedo quit working and if I accelerate quickly and then slow down, the check engine light comes on.... probably something to do with the ECM checking the VSS so that it may limit my speed!!

As far as changing the limiter in the ECM... I know you can completely turn OFF the limiter so that it doesn't limit EVER! You should post that question in the Prom Burning message board though... you'll get much more help there I'm sure!

Also, a little FYI! You can rig up a switch to the VSS and when you flip the switch (obviously only at high speeds) the VSS quits working and keeps the ECM from limiting the speed! However, I have heard that the speedo will quit working when you do this! I don't know for sure because I've never tried it!



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1986 Trans AM
305 TPI
Well over 200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Current Project: upgrade to a 355 TPI, 6" rods, 9.5:1 Compression, Stock TPI ported, 24#/hr LTI injectors, Hedman Shorty Headers, SBC Stock Casting heads pocket ported, Comp Cams XE262-14 TPI Cam, Ed Wright Fast Chip, Holley AFPR, TPIS airfoil, MSD wires, MSD 6-AL Box, Hypertech hot coil!!

 

A switch would not be a problem but you need to know exactly which wire you need to put a switch in. Obviously you can put a switch in the wire going to the ECM from the cable driven speedo, but on some other models I think mostly the 90-92 Camaros, the VSS goes either directly into the ECM first then out to the speedo and cruise control OR the VSS will go through a buffer first then to the speedo and ECM and cruise control depending on what enigine you have (TBI or TPI).