72 Stang to EFI conversion

[Scott Shotton]

Tim Raymond wrote:
> 
> >Oh Yeah!!  You'll need the oxygen sensor in the exhaust.  Very important
> >to closed loop operation and saving your pocket book from melting down
> >catalytic converters.
> >
> >The power steering pressure switch could be eliminated, but you might
> >want this with power steering.
> >
> >E-mail me if you have any specific questions
> >
> >Scott
> I have a couple of questions. Do I need the cats or can I ditch those. I
> have no emmisions tests to pass and as far as I know NY has no emmissions
> requirements for earlier cars. I'm planning on removing thermactor air. I
> think I'll keep the EGR. It wont hurt, but I don't think I have the vacumn
> regulator or solenoid or whatever it is. I can't find very clear info on the
> manuals I have. Where is the BAP mounted, I may or may not have that. I am
> also missing O2 sensors. I assume any junkyard O2 sensors will work. I'm not
> quite sure what to do about exhaust. Currently the car is stock '72 single
> exhaust. The '90 has headers. Third and final big problem is fuel delivery.
> Probably an inline pump, but I'll have to add a return line. I presently
> have the engine mostly disassembled so any mods here are easy. As soon as it
> warms up around here I can get to the car and find out more. Well, thanks
> for any help. It is going to be badly needed


The O2 sensor:  don't get a used one.  New ones should be less than
$100.  You can buy aftermarket adapters to weld onto the headers to
mount the sensor.

The fuel pump on the 90 is a high pressure in tank.  That swap would not
be practical.  See if you can find an in-line pump in the aftermarket. 
The fuel system operates at aprox. 40 psi.  The fuel pump should
probably be able to deliver 60-80psi or more.  I had one Ford with a bad
pressure regulator peg my gage at 100psi.  Yes, you will need a return
line.  The setup at the fuel rail should already be there.  Depending on
the fuel line already in the car, you may need to use high pressure fuel
line for the feed side.  Normal rubber fuel hose doesn't hold up to
40psi+ very well.

OK...  Now I have a diagram in front of me.

The components you definately need:
O2 sensors (my diagram for a 90 shows 2, one in each manifold/header)
ECT, TPS, ACT
MAP/BARO & MAF (my diagram shows both)
Idle air bypass solenoid
EEC power relay
Fuel pump relay

The components you may need:
EGR valve
EGR Vacuum regulator
Clutch/Neutral switch

Optional components:
Canister Purge components.
AC wide open throttle relay
Power steering pressure switch

NOTE!!!!  There is a 22K ohm resistor in line on the IDM circuit. 
Between the TFI IV ignition module and pin 4 of the PCM.

If you want a copy of the wiring diagrams, or If you want to know what
year engine managmeny system will be easier (and work) with a 72/90...
Let me know.

I might even be able to get you a deal on quality aftermarket parts (ie.
sensors) if you needed a handful of new ones.

Let me know.

Scott