is there any way to disable the vats system at the pcm wiring.

 

The fuel enable signal requirement from the VATS to the PCM can only be circumvented by programming or by buying a bypass module that imitates the signal.

 

thanks

 

There's always the resistor trick.

 

Maybe we need some more input by sw89lt1, but I was assuming by his sig that he has a transplanted LT1 into an earlier car and has no VATS module at all. If so, he may have nothing to do the resistor trick on.

 

i have the module but i want to get rid of any wires i don't need. does anyone know were i can get new plugins for the pcm wires.

 

i built a new wiring harness for the motor and i already disconected all the wires that it doesn't need. i had the vats tuned out but i got an exchange pcm from brian and i don't think this one has it tuned out. i got the car to start but it just ran for about 5 seconds.

 

I think you have another problem. VATs from what I understand, will only prevent it from starting. Once it does, I believe it's out of the picture.

Sounds like what you and Shoe have said here, you don't even need the TDM connected. If you don't have the proper resistance across pins 88 and 87 of the module and it still started, that proves the PCM doesn't need the fuel enable signal since the module couldn't put the fuel enable signal out. That also leads us to believe you aren't using the TD Relay either which is ok. But be sure you are using either the clutch or tranny position switch otherwise you could be in for trouble if you've had one too many and try to crank it in gear.

 

No, the VATS has 2 functions. It will keep the car from cranking (by virtue of the TDR) and it will keep the engine from running (fuel enable). If the TDR is bypassed, the engine will start, run for just a few seconds, then die. This gives another layer of protection like if a thief were to bypass the TDR.
I believe it must be that the PCM takes a second or two to ascertain the presence of the fuel enable signal. Whether this is true or not, I don't know, but it will act this way every time.

If he has no VATS module wired in and is able to crank the engine ok, then the PCM only needs the VATS programmed out or a bypass module to simulate the fuel enable signal. The bypass module is what a lot of people buy that put LT1s into hot rods or other conversions (unless they go the programming route).

 

the nut wasn't tight on the pcm ground wires
had to hot wire the starter to get it to turn over. i guess it the vats thats keeping it from turning over with the key. but it runs so i'll fix the rest this weekend.


thanks for the help anyway.

 

Do you (or anyone else) know how to do this with LT1 Edit?

 

do you have LT1 edit? if I remember, it is pretty easy, I had Dreamer1Q do a 94 PCM for me

 

yea, that's why I asked

 

You kind of left something out when you quoted me as saying "the PCM can only be circumvented by programming". That doesn't make much sense.