P70 Data Cable Testing

We have experienced several unexplained shutdowns of Jetcat engines recently. In several instances the data cables were suspected of contributing to problems. As a result we decided to perform some tests to identify what symptoms are realized when the cables fail.

A cable assembly was fabricated that ran through a box with an array of momentary switches that are normally closed. This assembly allows a momentary interruption of signal to any one of the conductors in the cable.


For this test, the following are the locations and numbers of conductors.








6 5 4 3 2 1
Looking at the receptacle in the engine/ecu









1 2 3 4 5 6
Looking at the end of the cable

This cable assembly was tested in 3 different configurations on a P70 engine and the results recorded.


The first test was with the data cable assembly connected from the ECU to the engine. The engine was powered up but not started. Each of the conductors was interrupted (open connection) with the following results displayed on the GSU:

Conductor and Resulting display on the GSU

1 No change to the display
2 EGT went from ambient temperature to flashing alternately between "xxx" and "E", RPM went to Zero when spinning the engine with air.
3 EGT went from ambient temperature to flashing alternately between "xxx" and "E", RPM remained active when spinning the engine with air.
4 EGT went from ambient temperature to flashing alternately between "xxx" and "E", RPM remained active when spinning the engine with air.
5 EGT went from ambient temperature to flashing alternately between "xxx" and "E", RPM went to Zero when spinning the engine with air.
6 EGT flashed alternately between "E" and temperatures around 950


The second test was also with the cable assembly connected from the ECU to the engine, but was conducted with the engine running. Each of the conductors was interrupted (open connection) with the following results displayed on the GSU:

Conductor and Resulting display on the GSU

1 No change to the display
2 EGT went from normal operating temperature to flashing alternately between "xxx" and "E", Engine shutdown with off condition of "Low RPM". Upon repowering, off condition indicated "Powerfail".
3 EGT went from normal operating temperature to flashing alternately between "xxx" and "E", Engine remained at same RPM and throttle became non responsive.
4 EGT went from normal operating temperature to flashing alternately between "xxx" and "E", Engine remained running and throttle was still active.
5 Display went to Jibberish, engine shutdown. When powered back up, off condition indicated "Powerfail"
6 EGT flashed alternately between "E" and temperatures around 950. No effect on throttle. All else OK.

The third test was with the cable assembly connected to the ECU and LED board. The engine was running during this test. Each of the conductors was interrupted (open connection) with the following results displayed on the GSU:

Conductor and Resulting display on the GSU

1 No change to the display, All items appear active.
2 Display went blank, engine slowly went to idle, then slowly back up to set RPM.
3 Display froze and retained last numbers for everything.
4 Display froze and retained last numbers for everything.
5 Display went blank, engine ran fine and responded to throttle.
6 No change to the display, All items appear active.

Similar tests will be performed on a P120 engine and results compared.