Disconnect and plug the vacuum hose to the MAP (Manifold
Air Pressure) sensor. Mass air systems do not measure
intake pressure but rather ambient air pressure.
We layed out the new conversion harness and began making
the connections and routing the wiring. As seen in step
6, we began with the connection at the MAF.
Position the end of the harness with the exposed wiring
towards the driver side firewall, near the main engine
harness. We'll make the connections later.
We routed the harness through the existing factory clamps
as shown here.
The injector leads are laid out on either side of the
manifold. Note that each injector connector on the new
harness is marked with the corresponding cylinder number.
Lay out 1 thru 4 on the passenger side of the manifold,
5-8 on the driver side.
Disconnect the existing fuel injector connects. We do
not recommend cutting them off, simply let them sit unattached,
or zip-tie them back to the factory harness.
Connect up all eight injectors,
pay attention to the marked cylinder numbers. The wires
are also cut to length, so in fact it is pretty straight
forward and nearly impossible to mix up the connections.
The injectors on the right side are incredibly difficult
to access due to the big truck upper intake. If you're
patient you can squeeze a hand under the plenum and disconnect
them. Then route the new harness underneath and make the
connections.
The conversion harness comes with one O2 sensor connector
which needs to connect to the new O2 sensor we plumbed
into the left (driver side) exhaust.
The conversion harness needs a good ground for the mass
air meter. We attached the supplied ring terminal to one
of the rear intake manifold bolts.
Check your speedometer cable at the transmission end.
It is likely you have a Vehicle Speed Sensor (VSS) attached
to the cable. If so you are set. If not you should procure
one and install it and wire it to the EEC with the leads
provided.
The harness kit includes three spare wires in the event
your speed density truck is not equipped with a VSS (pins
3 & 6) or a fuel pump monitor (pin 8). Install a VSS
and connect up the wiring. The fuel pump monitor wire
simply splices into the fuel pump relay terminal which
is positive 12V when the pump is on.
Big Ugly
Donor Work Trucks
During a recent trip to our favorite Pick 'n Pull we were
amazed to see the abundance of 1986-1990 F150 and F250 rigs.
In fact we spotted in the same yard a 5.0L, 5.8L and 7.5L
versions. They are all good options for engine upgrades, and
could all be successfully operated via a mass-air EFI system.
Disconnect and plug the vacuum hose to the MAP (Manifold
Air Pressure) sensor. Mass air systems do not measure
intake pressure but rather ambient air pressure.
We layed out the new conversion harness and began making
the connections and routing the wiring. As seen in step
6, we began with the connection at the MAF.
Position the end of the harness with the exposed wiring
towards the driver side firewall, near the main engine
harness. We'll make the connections later.
We routed the harness through the existing factory clamps
as shown here.
The injector leads are laid out on either side of the
manifold. Note that each injector connector on the new
harness is marked with the corresponding cylinder number.
Lay out 1 thru 4 on the passenger side of the manifold,
5-8 on the driver side.
Disconnect the existing fuel injector connects. We do
not recommend cutting them off, simply let them sit unattached,
or zip-tie them back to the factory harness. 
The injectors on the right side are incredibly difficult
to access due to the big truck upper intake. If you're
patient you can squeeze a hand under the plenum and disconnect
them. Then route the new harness underneath and make the
connections. 
The conversion harness comes with one O2 sensor connector
which needs to connect to the new O2 sensor we plumbed
into the left (driver side) exhaust.
The conversion harness needs a good ground for the mass
air meter. We attached the supplied ring terminal to one
of the rear intake manifold bolts.
Check your speedometer cable at the transmission end.
It is likely you have a Vehicle Speed Sensor (VSS) attached
to the cable. If so you are set. If not you should procure
one and install it and wire it to the EEC with the leads
provided.
The harness kit includes three spare wires in the event
your speed density truck is not equipped with a VSS (pins
3 & 6) or a fuel pump monitor (pin 8). Install a VSS
and connect up the wiring. The fuel pump monitor wire
simply splices into the fuel pump relay terminal which
is positive 12V when the pump is on.
