General Troubleshooting - Holley MPI PRO-JECTION Installation Tuning And Troubleshooting Manual

5 - Be sure all electrical connections are secure and wires are away from moving parts. Apply a fresh coat of silicone
dielectric grease to all electrical terminals to help conductivity and reduce corrosion.
6 - If a drop in performance is noticed, a dirty fuel filter may be the problem. Change as required.
7 - During extended periods of storage (60 days or more) gasoline my deteriorate due to oxidation. This can damage rubber
and other polymers in the fuel system. It may also clog fuel injectors. A commercially available fuel stabilizer should be
added to the fuel tank whenever actual or expected storage period exceeds 60 days. Follow the product instructions for
the amount of additive to use. The engine should be operated at idle for a minimum of ten minutes after the addition of
the stabilizer to assure that it reaches the throttle body.

17.0 GENERAL TROUBLESHOOTING

Double check ALL wiring connections and system voltages BEFORE replacing components. If you suspect an ECU or
component failure, check all other possible problems before replacing a component.
CONDITION
Fuel Pump fails to operate
No fuel from injectors
Engine runs rich
Engine runs lean
Hard starting (cold)
Hard starting (warm)
Poor performance
28
POSSIBLE CAUSE
- Open or blown fuse
- Poor ground connection
- Faulty fuel pump relay
- Faulty fuel pump
- Faulty ECU
- Open or blown fuse
- Poor ground connection
- Injector connection loose
- No fuel in tank
- Low fuel pressure
- High return fuel pressure
- No fuel pump
- No tach signal
- Faulty ECU
- High supply fuel pressure
- High return fuel pressure
- Incorrect calibration module settings
- MAP sensor hooked up improperly
- Faulty MAP sensor
- TPS setting incorrect
- Faulty TPS sensor
- Oxygen sensor mounted incorrectly
- Faulty oxygen sensor
- Low supply fuel pressure
- Incorrect calibration module settings
- Faulty MAP sensor
- TPS setting incorrect
- Faulty TPS sensor
- Faulty oxygen sensor
- Incorrect system sizing
- Faulty coolant temperature sensor -
- Faulty air charge temperature
sensor
- Faulty IAC motor
- Fuel pump not flowing fuel
- Engine flooding
- Faulty coolant temperature sensor
- Faulty air charge temperature
sensor
- Fuel pump not flowing fuel
- Calibration module not adjusted
properly
REMEDY
- Replace fuse
- Clean ground and tighten securely
- See Testing Relay section
- Check for voltage and ground at pump. If voltage
and ground are present, replace pump.
- Replace ECU
- Replace fuse
- Clean ground and tighten securely
- Inspect and clean connections, reconnect
- Add fuel to tank
- Install pressure gauges and adjust pressure.
- Kinked or restricted fuel line. Repair kinks and
remove obstructions from lines
- See Item 1 above
- See Tachometer section of Electrical Connections
- Replace ECU
- Install pressure gauges and adjust pressure.
- Kinked or restricted fuel line. Repair kinks and
remove obstructions from lines
- See Tuning section
- Using vacuum gauge, ensure MAP sensor is hooked
up to full manifold vacuum
- See Testing MAP Sensor section
- Adjust TPS. See TPS Adjustment section
- Replace TPS
- See Oxygen Sensor installation section of
instructions
- Replace oxygen sensor
- Install pressure gauges and adjust pressure.
- See Tuning section
- See Testing MAP Sensor section
- Adjust TPS. See TPS Adjustment section
- Replace TPS
- Replace oxygen sensor
- See Choosing the Right System
- See Testing Coolant Temperature Sensor section
- See Testing Air Charge Temperature Sensor
section
- See Testing IAC section
- See Item 1 of Troubleshooting
- Use "Clear Flood" mode. See Section 15.1.
Inspect injectors after shutting off engine for injector
leakage. Replace leaking injectors.
- See Testing Coolant Temperature Sensor section
- See Testing Air Charge Temperature Sensor
section
- See Item 1 of Troubleshooting
- See Tuning section