FI Question
 

I finally started going thru my 74 2.0, I started checking all the FI stuff per Brad Anders wonderful site, the ECU is a 75 ECU, will this effect the way the car runs, I noticed the waveform count is different. Should I replace it?

Thanks,

The '75-'76 ECU has a couple of differences from the '74 2.0 ECU. It has a different speed correction waveform, and it has a different circuit for overrun shutoff. My guess (nothing more) is that it will operate essentially the same as the earlier ECU.

I've switched both ways, early to late, late to early. No problems. I've run 1.7 brains with 2.0's and vice-versa, no problems.

I could just be lucky, but then again, if I was lucky I woulda had a 6...

As Jason says, there isn't much difference between the various D-Jet ECU's used on the 914. The major item that varies in D-Jet ECU's is the engine speed mixture correction curve, derived from the volumetric efficiency (VE) curve (pumping efficiency) of the motor. This correction is realized as a OR'ed set of waveform generators in the ECU and is custom to the particular motor. I would wager that the VE curve of the 1.7 and 2.0 motors is very similar, hence the interchangability. Other differences in the ECU's are in the overrun shut-off control, and in the hot starting circuits, both of which don't have much effect on general performance.