I have BS3 coming and I was curious about the install. What wiring goes and what stays in the car. I've heard it's possible to piggyback it and still run the stock gauges. I don't really want to buy the speed inc harness. I'll just do autometer gauges if it comes to that. Right now I have the heads off the car. Would it be easier to install now? Where is everyone mounting the box and routing the harness. Thanks for any insight.

 

I would like to know also since I have BS3 on the way too.

 

One of the easier places and kinda tucked away is hiding it right under the heater controls in the center consol. And then running the wire pack out 3" to the right of the throttle cable (facing the firewall from the inside).

To make the Tach and spedo work, you have to Y the crank sensor harness, and for the spedo do the same, BUT you have to reverse one of the legs of it. So the bs3 gets -+ and the gauges get +- , if not then neither will be happy as they both want to ground it.

 

so if the computer believes the car is running by the cranks signal will the fuelpump wire have power?

 

The fuel pump works as from the factory. All you do with the bs3 is tie it into the crank sensor to pick up the position.

 

So what wiring stays and what can go? To keep the stock gauges the stock pcm needs to stay correct?

 

The easiest way to wire the setup is just to T into the VSS and the crank sensor and keep the factory PCM in place with all wiring. If you wish to get rid of a bit of wiring, then you would have to layout the wiring harness and de-pin the necessary items.

The 98 cars are a bit diffrent then the 99+ , a sponsor on here does make a PNP harness for the 99+ cars.

 

So those 2 sensors are the only ones that need spliced? I have a 98 also.

 

When i installed bigstuff on my car we just got rid of the stock engine harness bigstuff will give you the complete engine harness so it's pretty much plug and play.I also used the fuel pump trigger wire from bigstuff to turn on my pump.I run aftermarket guages so the fatory stuff really doesn't matter to me.IMO the fatory gages are so off that if you have anykind of good race motor you need good gages.You will also have to get somekind of baseline tune because the box has no file.You can down load one file that is avalible but if your setup is not even close to there file it's real hard to get tuned if your new with the software.

 

just cut or unpin from the stock computer all and only the wires that bs3 makes redundant EXEPT
crank signal, water temperature, vss out (you would keep all of the m6 harness if standard shift)

just put the new bs3 water temp to a new sensor in the other head.

you want to head the harness through the firewall near passenger side.. to far to the passenger side and your coil pack harness will be tight, also the map wires are very short you may choose to lengthen them off the bat if you are going to run a big 'boost' map sensor somewhere else.

i use the fuel pump outputs from bs3 to run my first and second pump