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Common electrical problems/cures: (troubleshooting)

FORWARD: CLOSE BOTTLE VALVE WHILE PERFORMING DIAGNOSTICS ON SYSTEM. MOST DIAGNOSTICS WILL BE DONE WITH KEY “ON” BUT ENGINE NOT RUNNING. IT’S ALSO ADVISABLE TO RELIEVE (PURGE) ANY N2O IN THE LINE AFTER YOU CLOSE THE BOTTLE VALVE. FUEL PRESSURE STAYS IN THE LINE FOR QUITE A WHILE AFTER THE KEY IS OFF. IT ALSO STARTS PRESSURE WHEN THE KEY IS ON. IF YOU HAVE A WET SYSTEM, DISCONNECT THE WIRES TO THE FUEL SOLENOID SO IT CANNOT ACTIVATE DURING DIAGNOSTICS.

Problem: Switches light up, but solenoid(s) won’t open
1. Bypass the FPSS switch by placing a jumper a wire across the two terminals. Do the same with the WOT micro switch (if you have a mechanical switch). If you’ve used a Window Switch, you’ll have to jumper that one too. Now the solenoid should activate directly with your on/off switch.
a. If not, check the 12v to the relay. Once again, it should show 12v with your on/off switch.
b. If no 12v to relay, go back over your wiring and check fuses. Make sure you’re bypassing the WOT, FPSS, and Window Switches.
2. If you’re getting the relay to engage, but not the solenoid, check the power / ground to the solenoid.
COMMON MISTAKE HERE: Most non electrical people don’t think about wire gauge and current carrying capacity. Solenoids can draw upward of 20 amps instantaneously. Most starters draw twice that. Look at your starter wire and think of ½ that. DO NOT gang the two solenoid wires together and then run ONE wire to ground. (unless you’re using 10 awg wire or thicker). It’s best just to run TWO 12 awg. wires with lugs to a common (well cleaned) ground point. GROUND IS THE MOST IMPORTANT AND LEAST TENDED TO CONNECTION. Also, long wire lengths loose capacity. If you’re running long lengths, get bigger wire. Figure one size bigger on the wire for every 5-7 feet.

Problem: System Activates, but then shuts off:
1. This can be caused by any one of the “cut off” switches. Easiest thing to do is bypass them (wot, fpss, ws) and then put them back in-line one at a time. Check:
a. Fuel Pressure, and activation pressure on your fpss. Maybe it’s set too low. You can check it with an air compressor and a DVM.
b. WOT switch position (and make sure you’re using the correct TWO terminals. Usually “COM” and “NO”.
c. Window switch rpm settings. Even for testing, set it above 1500 (on) and have 200-300 rpm difference (off).
2. Go back and read #2 above and make sure you’ve used sufficient wire gauge for solenoids. Insufficient wire capability = no worky.

Problem: System "pulses" on/off like surging.
1. If the jetting is correct, and you suspect the problem being electrical, it could be the same as above, it's just turning on, then off, then on etc.

Problem: Blows fuses every time it’s activated:
1. This one is usually easy to find. Open your switch panel and do a continuity check between power and ground. You’ll probably find a direct short. What seems to happen a lot is that people get confused with the WOT switch and the FPSS switch. These switches are NOT power and ground switches. They are a “connect / disconnect” switch. There should never be power on one side and ground on the other. Most of the schematics shown in the stickies show these switches breaking the ground side of the circuit. Like taking a wire, cutting into two pieces (disconnect) and then connecting the two together again (connect).
2. Another possibility is that you have too many devices (heater, solenoids) running off one fuse. Heaters are 8 or more AMPS by themselves. If you have a 200 watt heater, it’s drawing 17 amps. (p=e*i).
3. Lastly, you may have the switch wired incorrectly. Check to see that COM (usually middle but not always) is NOT connected to power OR ground. The COM terminal should go to the device you’re controlling, ie: relay, heater (or heater relay if used) etc.

Problem: My switches are getting HOT!!!
1. You’re drawing too much power through the switch. Put a relay on the line. See relay operation attachment below. Switches have a rating, usually 5-15 amps.
2. Get a switch with an LED in it instead of a light bulb. Cheap switches have light bulbs in them and they get hot.

When performing diagnostics on your system, a 12v light probe is extremely handy here because you can see the light from inside the car. This may show a 12v connection but it WILL NOT tell you that the wire is sufficient for the current you’re trying to put through it. Think of it like a river.. the “voltage” is like the river’s width/depth. It’s the “amount” of water. The current is the amount of “flow”. If you restrict the flow, you just won’t get all the water from one side to the other. (no worky)