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2.3L ('83-'97) Efi spark timing way off


Active Member
Aug 5, 2017
Reaction score
new york
Vehicle Year
Make / Model
ford ranger
Engine Type
2.3 (4 Cylinder)
Engine Size
soon-to-fire up 2.3 turbo lima
2WD / 4WD
Total Lift
Some wiring diagrams here: https://www.therangerstation.com/tech_library/turbo_swap_wiring.shtml

You can't get higher that battery voltage, engine off, so not sure why you would get those higher voltage readings

VREF(reference voltage) should be 5volts
SIG RTN(signal return) should read as Ground
But these can be reverse on some years

Those are 2 of the 4 wires on VAF unit
One of the other wires is for VAT(air temp)
And one for VAF(air flow)
These 2 should read less than 5volts, thats the sensor voltage the computer uses to determine air temp and air flow respectively
found some broken connection to the vane on the harness, rewired the entire signal return ground to make sure it didn’t have hidden shorts. I have 5v in all the right places, continuity between ecm and all connections to all sensors, yet I still get error codes for every single sensor connected to the signal return 46 pins (ect, act, vaf etc) and although I get 5v and continuity to ECM at the vane, the voltages at VAF and VAT are off (4.70v and like, 19v?), so there must be a bad ground.

I notice the following:

key off: the ecm grounds and signal return pin 46 all beep for continuity to battery ground and ground in general.
Key on: none of those beep for continuity. Does that mean the ecm isn’t properly grounded?

happy Halloween! Guess I went as a diy mechanic this year..

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