lt1badbird

iTrader: (-1)

How many people here have gotten rid of the stock pcm/ecm completely and replaced it totally with a FAST computer? and how many have used it to piggyback with the stock computer?

What are the pro's and con's of each?
what will and wont function if i ditch the factory computer all together.
im not worried about a/c, air pump, emissions, foglights, horns, airbag sensors.
I am only concerned with what i need to keep to make the car run and drive Will the factory guages not work with just the FAST?

I had planed on ditching the stock computer all together and only running the original FAST with msd digital 6, hvc II coil, conventional rear mounted dist., and a msd crank trigger setup.

Im all ears to any and everything i need to know on the subject of standalone vs piggybacking the FAST.

LT1 car btw

BizZzatch350

iTrader: (33)

This is the route I'm going, I had Brian Macey (Recomended by FAST) build an engine harness for the XFI, it lets you keep the stock gauges working via the factory ECM. The pro's of this set up are, ease of instaltion since you have a custom built harness for your specific application. It isn't plug and play but it's as close as your going to get and comes with instructions. The harness wasn't cheap, his prices have gone up but it's an easy way out when doing an after market computer.

Nostang

iTrader: (4)

Also, the piggy back setup is necessary (I think) if you need to pass OBD2 inspection. Otherwise, I would just go to the stand alone and throw some autometer gauges in the dash.

I wonder if there is a way you could get the stock computer to read obd2 readiness status but only be hooked up to a 12 volt soruce and to the obd2 connector under the dash?

lt1badbird

iTrader: (-1)

i dont need to pass any inspections like i said i only need the car to run and drive. just rying to find out exactly what im gonna have to deal with ditching the stock ecm.

Nostang

iTrader: (4)

Then you should go stand alone and replace the dash gauges. That is the route I would go. All your headlights and accessories will work as normal. The PCM only controls the engine, fuel pump relay, and the speedo and tach gauges.

Tony Shepherd

iTrader: (4)

The only reason I kept the stock PCM (which is NOT piggybacked to my XFI) is to keep the speedo. I have a factory gauge cluster. Your temp guage, fuel level, voltage, oil pressure....ect runs straight off the sending units so the stock PCM does not control that. You will have to run the wires for those minus the fuel which is already done. I just ran them through my XFI harness loom. All the stock PCM does for me is run the speedometer.

Hope that helps.

lt1badbird

iTrader: (-1)

thanks alot tony that helps a ton. I knew youd be one of the guys with the answer if you saw this