Jake88maro

hey guys heres some more info on my car, im doing a 6.0 lsx swap with a t56 and using the painless harness part number 10201 to wire the chassis and then another painless lsx swap harness for the motor. my question is how can i get my stock guages to work like speedo, temp, oil pressure, and fuel. the tach is easy lol one wire signal. but im completely lost on how to get the speedo and stuff to work with this aftermarket harness?? any input is appreciated!!!

Jake88maro

anyone lol??

BigBadLou

iTrader: (3)

Fuel gauge - leave intact if you are keeping the stock fuel sender.
Temp gauge - keep the old sender and just plumb it into the cooling passages (you can use a "tee" to connect multiple temperature senders to the same port).
Oil pressure - again, keep the old sender and plumb it into the oil pressure rail somewhere on the new engine.
Tachometer - not as easy as you think. You have two basic options:
A) tune the new LSx ECM to provide the right tach signal and wire that into your tach.
B) get an aftermarket tach adapter (coincidentally, I have one that I don't need) for distributor-less engines.
Speedometer - this one is the worst because you have a mechanical gauge but now will have an electronic VSS in the transmission. You can either buy an expensive mechanical pickup and adapter for the T56 or you can install an electronic speedometer (or the whole LSx dash, for that matter, which would solve a lot of your problems - and it fits in our third-gens, btw).

Hope this helps.
Lou

madonna

iTrader: (5)

An 87 Trans Am GTA already have a 140 mph electronic speedometer with a VSS, so only need to give it the correct signal from the new ecu or transmission

BigBadLou

iTrader: (3)

D'oh, you are right, I missed the "87 GTA" in the title, I went by the username.
Thanks for straightening me out.

Ok, if the car already has an electronic speedometer, you need to either reprogram the ECM to provide fewer pulses for your speedometer (I am NOT sure whether that is possible or not, check with whoever will be flashing your ECM) or you will need to install a pulse divider to drop the frequency from the T56 down to what your speedometer can handle.

Jake88maro

wow thanks i appreciate all of this information! i will get back with you on the tach signal adapter!
my last question is you cant just hook the vss to a dakota digital box and fix the pulse signal for the stock speedo??

BigBadLou

iTrader: (3)

If the Dakota digital box has that kind of range of frequency adaptation then you could do that. I myself am not familiar with the box much so I cannot tell you whether it will work for you or not. You would need to find documentation somewhere.