JasonC SBB

AEM reworked the boxes to short Inj1 to Inj9, and Inj2 to Inj10, in order to make them work with non-CA 91-93 cars which have paired injectors. "RevB modD" stickers have this but "RevB ModA" do not. I don't know about ModB and ModC.

VVT uses Inj9 and Inj10 outputs. If you try to use VVT you need to use Inj9 (VVC#1) or Inj10 (VVC#2). If you use say, Inj9 and also use Inj1, because they are shorted, the VVT algorithm will lock your Inj1 open and the cylinder will flood.

One solution is to use Inj5 in place of Inj1 and reconfig the software.

Another solution is to undo the shorts. If you open the box and examine the circuit board, you will see 4 insulated wire jumpers. 2 shortish (~ 2") ones and 2 longer ones. The 2 short ones jump the following connector pins:

1) 2V (Inj 2) to 3P (Inj10)
2) 2U (Inj 1) to 3O (Inj9)

Just remove them.


BTW RevB ModD 9and not ModA) also jumps the anodes D1 and D2 together. I don't know what it's for, but the anode of D2 routes to 12V_switched (pin 1B)


The other revA mods (which is also in revD ) appear to fix the tach output, cutting one trace and connecting to LS9. There is also a 1K pulldown resistor with one end connected to the tach output.

The other revD mods remove Q1 - Q5 which are for inverting the 5 IG outputs. (unused in the miata which is high to dwell).