problems with a 90 to 91 motor swap

[macstsi]

Im swaping the motor out of a 90 tsi in to a 91 tsi, and ive run into a few differnces. On the front of the motor theres a little box that says- power tr unit, on it. and the 90 has 5 wires and the 91 has 7. What is this and why is it different? and the harness that goes on top of the intake there are a few more plug ins then here are on the 90 harness what are they for? I think thats it for now, thanks

 

[fivestardsm]

You need the swap out the throttle bodies so that all the plug-ins are the same because the TPS's are diff. Also you need to change the coils and transistor, and the CAS on the intake cam, these too have diff. plug-in connectors.

Steve.

 

[laserblue]

You write "why is it different?"......... It's a different year!! Cars change... updates happen... circuits improve. For example, a '90 uses that little box to send pulses to the dash tach, but a '91 uses a pin on the power transistor. Several other wires and parts are different and may not be adaptable to a different year.
If nothing ever changed, we'd all still be driving around in Stanley Steamers.:laugh: :laugh: