February 2022

BY Kevin Toms M y subject for this piece is a 2006 Hyundai Matrix. It was recovered by one of the breakdown services as a non-runner, and accompanied by the customer request to replace the fuel pump. This was what had been diagnosed by the breakdown service technician. What is real? While talking with the customer, it was explained that we could do that if he stipulated it, but our preferred course of action was that we do our own diagnosis to confirm or find the cause of the failure. We felt this was preferable to just firing the parts cannon at the car and hoping for the best. With a timeframe agreed for us to do our own diagnostic evaluation, the vehicle was manoeuvred into the workshop. First things first, verify no fuel pump activation. So, from being seated in the vehicle, I turned the key on and heard no sound from the fuel pump. I then tried spinning the engine over to start the engine, but there was still no sound from the fuel pump. The next step was to check that the crash switch was closed, as it is so simple to access and then check the 10-amp fuse for the pump. All was ok. Next step; Access the tank unit wiring. This was easy as the rear seats had been taken out. I then looked at the wiring diagram (see Fig.1). With the wires for the fuel pump picked out and circuits highlighted, next I tested my trusty bulb test light was working on the battery (always test your equipment is working before using it) and then 34 AFTERMARKET FEBRUARY 2022 TECHNICAL www.aftermarketonline.net ENTER THE MATRIX Yet another new contributor; This time it is 2021’s Top Technician Kevin Toms, who in his first article seeks to answer the eternal question; “When is a pump not a pump?” proceeded to back-probe in to the pump connector. With this done and the light now hanging from the headrest so it could easily be seen from both inside and outside of the vehicle, the ignition was cycled to on. There was no reaction; The test light failed to illuminate, so no supply. This was the reason for no fuel pump operation. Fig 1.