Quote:
Originally Posted by Graham
Mach4,
But for life of me, I can't understand how the tach would be controlled by an EGR controller on an EGRless engine  |
While there are no EGR components on the engine to control, the controller (and I would guess, the wiring and engine bay components) were left intact. Here's the diagram of the vacuum system showing the EGR stuff (the controller is circled)
Here's the wiring diagram
And the detail showing how pin 25 goes to the tach
My guess is that when they swapped the engine they left the transmission alone, so you've still got the tach pickup off the flywheel. If they swapped in the earlier transmission then the pickup would be off the harmonic balancer and there will be a tach amp on the fender well. They would also have had to swap in either a tach element or an entire cluster as the tach gauge itself is different.
I spent a lot of time sorting this stuff out when I did the 617 engine swap in the 107.