JC

I had my motor out and I swapped the sensors to my new motor. I lined up the crank and cam sprockets dot to dot and then slid the sensors in. Was that the correct way? I think it is but, I want to be sure.

Is there anything else I should do related to the sensors before I fire it up?

JC

Okay, i just need a quick yes or no.

jmX

Last time I installed a fresh motor, we just bolted the sensors on and fired it up. Nothing special had to be done at all.

JC

Thanks jmX I didn't know if they had to be lined up with a certain area on the reluctor wheel or something.

jmX

I'll double check the manuals tonight to make sure if nobody else chimes in. I honestly didn't even check them when we put the motor in...just bolted it on and installed the motor. Coulda just lucked out when it fired right up

Jason99T/A

iTrader: (21)

Just bolt in and go. If you are using a new crank, PCM, or crank position sensor, you will have to perform a Crank Position relearn with a Tech2.

JC

I swapped my old crank and my old cam position sensors into another used shortblock. So I need to do the relearn?

SilverGhost

iTrader: (53)

I've always wondered about that relearn myself. I put a new motor in my car recently and have new sensors in it and never did that relearn...in what ways would/could/should that negatively effect the car??

jmX

Why would a new crank require the relearn? Why would a new sensor require that too? I've never fully understood when the tech2 proceedure is actually needed, and when it isnt.

BTW, Doesn't EFILive Pro let you do that relearn now?

Jason99T/A

iTrader: (21)

I have only had to do the Crank Position relearn one time on a car. This was when a new motor and PCM were installed in a customer's car.

According to GM, a relearn is needed whenever the following conditions are met:

- engine replacement
- PCM replacement
- anytime the crank pos. sensor to reluctor wheel gap is changed (new crankshaft, sensor,etc)
- if the battery is disconnected when the ignition is still on the ON position

The PCM uses the crank pos. sensor to keep the injector and ignition systems in syncronization, and to detect misfires. As the crankshaft is rotated, the reluctor wheel teeth interupt a magnetic field coming from the sensor. The PCM times the interval between these "pulses" and compares each new interval with the previous one. This is how the PCM finds out if an excessive change in crankshaft speed has occured. When the change is large enough, a misfire is considered detected.

And yes, EFI Live Pro can do the relearn as far as I know.

Jason

SilverGhost

iTrader: (53)

HMMM..so I'm still wondering what could happen if I don't do it. The car is running great, never throws a light or anything..did something happen that made you do the relearn with that car? Or did you just do it for sake of proper procedure?