Accel/dfi – Mallory Ignition ACCEL CHEVROLET APPLICATIONS (including LT-1) 74022 User Manual

Page 9

ACCEL/DFI

The ACCEL/DFI system comes with an oxygen sensor and a
M18 X 1.5 hex nut. This nut is to be welded to the collector
(preferably away from the passenger side) of the exhaust
header, if you are not using headers, please refer to figure I.
You will want to mount this closest to the header flange (or
exhaust manifold) without interfering with exhaust
connecting flange.

Prior to mounting the nut, drill a perpendicular 5/8”
diameter hole in the exhaust pipe or header collector.

If using a stock TPI or 58mm throttle body, use ACCEL
Powerfilter part number 74550. If you are using a 750 CFM or
1200 CFM throttle body, these throttle bodies have a 5-1/8”
filter surface, therefore any carburetor style air cleaner
will work.

At this point all the electrical connections should be made
between the sensors, computer, and optional equipment.
Keep in mind that you will have at least one extra connector
that will not be used on the main wiring harness. Now
connect the positive terminal to the positive side of the
battery, and the ground wires (see figure B or figure C
depending on application) to the negative battery terminal.

Prior to adjusting the TPS the throttle blades need to be
initially set. This can be done by backing the throttle stop
screw out so the throttle blades bottom out in the bore.
ACCEL/DFI has found a good starting position on a stock
throttle body to be four (4) turns in, once the screw makes
contact with the throttle blade tang. Again, this is just a
starting point and every application will vary. Next loosen
the screws that secure the TPS.

With the motor running, measure the voltage across pins
A & B of the TPS with a volt meter. Rotate the sensor until
+0.5 volts is shown. This can also be done using CALMAP,
consult your CALMAP users guide.

VIII – MOUNTING THE OXYGEN SENSOR

IX – AIR CLEANER ASSEMBLY

X – TPS ADJUSTMENT