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Engine will not start:
1. Check FUELCUT/MANPRESS parameter. Should read NO LIMIT.
2. Try turning mixture knob richer while cranking. START values might have to be increased.
3. Check all connections on EM-5 main harness, ignition.
4. Check both ground wires from EM-5, one from main harness and one from injector drive harness.
5. Check MP reading in Gauge1 mode. If between 0 to 10 inches, check MAP sensor connector for broken
wires, or bad contact in the terminals. Try new MAP sensor
6. Check for +12V to injectors while engine is cranking.
7. Check if the programmer goes blank during cranking. Check battery voltage. Should be at least 9 volts while
cranking, and 12.0 volts when not cranking.
8. Check for spark.
9. Check ignition timing while engine is cranking.
10. Check if the fuel pump is running.
11. If fuel pump relay is used, check connections.
12. Check for fuel flow out of regulator drain to return of fuel tank.
13. Check for injectors clicking.
14. Check FUELCUT/RPM parameter. Should read NO LIMIT, or a high RPM.
15. Check compression and camshaft timing.
16. Check Hall sensor gap and alignment with magnets.
17. If using a noid light, make sure all of the injector plugs are unplugged from every injector. Check +12v
supply to injectors and check grounds on ECU. Use noid lights as a last resort. LED noid lights are much
better than incandescent.
It is highly unlikely that there is a problem with the EM-5, since many ECU’s in the past have been returned with
“no fuel” symptoms, but they work just fine so check all of the above carefully.
Will not rev up or has Miss:
1. Check ACCPUMP values. May be too high.
2. Check AP number in gauge 2 mode. Should be zero when throttle is stable. Check this with engine running.
May only show up at certain RPM’s.
3. Check for leaking fuel pressure regulator diaphragm. If fuel in vacuum reference hose then replace the
regulator.
4. Check for bad values in RPM or MAP parameters. Could be crossing a bad value anywhere.
5. Hall sensor mount is vibrating. Stronger bracket required. Watch RPM reading in gauge 1 for ERR
message.
6. Check FUELCUT/MANPRESS and FUELCUT/RPM parameters.
7. Check resistance of all spark plug wires. Possible poor crimp at the end of a wire causing arcing.
8. Try a different brand of spark plug wires.
9. If Knock sensor is being used, Knock Sense value may be too high. If there is no knock sensor on the SDS,
system set Knock Sense to 1, and Knock Retard to zero.
Unstable RPM reading in Gauge 1 mode.
Check hall sensor alignments and magnets. Bracket must not vibrate or flex.
Idle speed too high:
1. Throttle stop may be set to hold open throttle plate. Make adjustment.
2. Vacuum leak.
Idle speed too slow:
1. Mixture could be too rich or too lean. Adjust fuel values for fastest idle speed, then if idle speed is still too
slow, adjust throttle stop or air bypass screw for faster idle speed.
Rough idle:
1. Bad ignition wire arcing to ground.
2. Mixture needs to be rich for best idle. Try adjusting fuel values until too rich then lower the values until
engine is smooth.
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