The following faults and the LED Diagnostics are all related to installation problems. If you don't have one of the issues below call us and we will help locate the problem or fine tune your system.

* No activity when turning the power switch ON.

Verify: Ground connection. Connect a jumper from the Controller base plate to a reliable ground.

Check: Harness pin #4 (white wire) for 12/24 volts. Fuse, supply CB closed and all connections from the power source to the harness (white wire).  

* Pump does not run when turning the power switch ON.

Apply 12/24 volts to the harness pins 11 and 12 (grey wires) momentarily. The pump should run.

* iStart primes normally and the engine fires but only runs for 2-5 seconds.

Check: That the pump runs when the starter is engaged. That the start signal (green wire) is connected to a terminal that is powered when the starter is engaged. That the P-Lead  (orange wire) is connected to the impulse mag operating during start.

* A cold engine that doesn't fire.

Disconnect the fuel line at the manifold (spider) and verify fuel flow when the power switch is turned on.

* Engine dies after the light begins flashing for mixture advance.

Moving the throttle or an RPM change in excess of 100 RPM  for any reason after the light begins flashing will cause iStart to shut down. (Safety feature)

* When turning the power switch ON, the light flashes once and the pump runs continuously.

The start signal (green wire) is incorrectly connected to an always powered source. (e.g. the B post on a key start switch)

*  When turning the power switch ON the light flashes slowly and pump does not run.

The thermistor is damaged, grounded or the wire is broken/disconnected.

* The engine surges after initial firing.

The throttle was opened excessively. Reduce and try again.

* On hot starts the engine fires but almost immediately quits.

There is often residual fuel/vapor at the cylinders due to vaporizing fuel in the lines after shutdown. This may result in a cylinder or two firing after just a few blades but will not sustain the start. Keep the starter engaged through this point and release it when you have a good start.


Remove the harness plug, remove the Controller cover and reinstall the harness plug.

Locate the LED group opposite the harness plug on the circuit board. The LED's are labeled: DIAG, START, PUMP, P-LEAD and INJ.

The following is the correct sequence of LED activities during the pre start and start activities.

Turning the iStart power switch ON

1. DIAG  ON then OFF






5. DIAG flashing

Engaging the starter

1. START and PUMP ON (INJ may or may not be ON)

When the engine fires and runs


2. DIAG, P-LEAD and INJ flashing

After mixture RICH, all lights OFF



!! ALWAYS treat troubleshooting with respect !!

Troubleshooting often involves HOT mags, engaging the starter, fuel in the cylinders, etc. With any piston engine, there is always the risk of unintended engine firing. Do not become complacent during the troubleshooting process. After making hundreds of starts during our testing we have seen that engaging the starter or simply moving the prop can become commonplace and not be treated with the respect it deserves.

ALWAYS: Chock the aircraft. Verify the prop area is clear of personnel and obstructions. Do not let anyone move the prop. If engaging the starter, VERIFY again the prop is clear. EVERY TIME!