Holley 02121NOS - Manual (Page 19)

Mismatched N
2
O/fuel
jetting.
Compare jetting to recommended values. Install correct jets.
Excessive fuel
pressure. Install fuel pressure gauge, such as NOS
P/N 15906NOS, in the fuel line. Measure
the pressure during acceleration with the
system activated. Regulate pressure down,
or install smaller fuel
jetting.
Loose nitrous solenoid
wiring. Inspect the solenoid wiring. Repair wiring.
Malfunctioning nitrous
solenoid. WARNING: Solenoid discharges nitrous
at a high rate. Don’t inhale nitrous; death
may occur. Skin contact may cause
frostbite. Close bottle valve. Disconnect
the nitrous solenoid outlet port.
Disconnect the solenoid (+) lead. Open
the nitrous bottle valve. Connect the
+12V to the solenoid. Solenoid should
discharge N
2
O at a high rate.
Rebuild solenoid.
System wired
incorrectly. Compare nitrous wiring to schematic
(Figure 12). Wire system per
instructions.
Loose ground wire(s). Connect 12V test light to battery (+)
terminal. Check for continuity at grounds
noted in Fig. 12. Tighten/repair loose
grounds.
Malfunctioning arming
switch. Turn arming switch on. Connect 12V test
light to battery (-) terminal. Check for
power at pole #2. Replace pushbutton
No power to arming
switch. Connect 12V test light to battery (-)
terminal. Check for power at pole #1 on
arming switch. Repair wiring.
Malfunctioning throttle
microswitch. Temporarily disconnect power relay red
wire from microswitch. Connect 12V test
light to battery (-) terminal. Manually set
microswitch ON. Check for continuity at
microswitch positive terminal (Fig. 12). Replace throttle
microswitch.
No change in performance
when system is activated.
Overly rich fuel
condition. Check for black smoke or backfiring
through exhaust with system activated. Install smaller fuel jet or
decrease fuel pressure.
Excessive ignition
timing. Check ignition timing. Reduce timing in 2°
increments.
Inadequate octane fuel. Use higher octane fuel.
Spark plug heat range
too high. Reduce spark plug heat
range (maximum 2 steps).
Engine detonates mildly
when system is activated.
Too much nitrous flow. Reduce nitrous jetting.
Inadequate fuel delivery
due to:
Plugged fuel filter.
Inspect fuel filter.
Clean or replace filter.
Crimped fuel line. Inspect fuel line. Replace crimped line.
Engine detonates heavily
when system is activated.
Weak fuel pump. Install fuel pressure gauge, such as NOS
P/N 15906NOS, in the fuel line. Run
engine under load at wide-open throttle,
with system activated. Fuel pressure
should be within 5 PSI of fuel pressure at
idle. Repair/replace fuel pump.
Excessive spark plug
gap. Inspect spark plugs. Set spark plug gap at
0.030” to 0.035”. High-rpm misfire when
system is activated.
Weak ignition/ignition
component failure. Inspect components (plug wires,
distributor cap, etc.) Replace worn
components.
Inadequate supply of
nitrous. Check bottle weight. Replace with full bottle. Surges under acceleration
when system is activated.
Bottle mounted
incorrectly. Compare bottle position and orientation to
instructions (Figures 2 & 3). Mount or orient bottle
correctly.
19