We then connected the sensors, then disconnected the battery for 30 seconds to clear the faults in memory. We then checked the Water Temperature Sensor and MAP sensor and noticed they were both unplugged. We noticed the distributor was fine, so asked our lecturer why we were getting a fault, and he explained that because we had previously disconnected the distributor the ECU had stored the fault in the system. We also got codes 22 and 31 which was the Water Temperature Circuit, and the Vacuum Sensor Circuit.Īfter we noted all the faults we checked under the hood to do a visual inspection of the parts.

We got code 12 which was a G,NE Signal circuit, which we got from disconnecting the distributor. We found out how to check for flash codes by reading the Toyota Service Manual.Īfter we connected the jumper wire properly, we checked for the flash code on the dash board. In order to test the vehicle flash codes, we used a jumper wire that connected from TE1 to E1 on the diagnosis box under the hood. Set Multimeter to Hz with car idling and measure frequency Voltage to injectors with the car idling.Ĭylinder1 Cylinder 2 Cylinder 3 Cylinder4Ĭhecking with LED test light on each cylinder (did the LED flash?)Ĭylinder 1 Cylinder 2 Cylinder 3 Cylinder 4Īccelerate the engine with short fast bursts and measure the % (duty cycle)Ĭylinder 1 Cylinder 2 Cylinder 3 Cylinder 4 At WOT (wide open throttle) the vacuum drops to 0 Hg, the fuel pressure then increases to 38 psi. With the engine at idle, the vacuum is around 20 Hg, the fuel pressure is approx 32. The fuel pressure regulator maintains the fuel pressure at around 32-38 psi. Any fuel left over gets recycled, and goes down the return line and back into the fuel tank. The fuel then travels to the injectors where it gets sprayed into the combustion chamber.

These filters should be replaced every 30,000km. It is the vapour of the fuel that is inflammable, not the actual fuel itself. This is why we should never run the car on a empty tank, or bench test the fuel pump. The fuel is then transfered to a fuel filter, which collects all the dirt and grime out of the fuel. The fuel in the fuel tank, gets pumped up by a fuel pump. As the fuel pump operates, it creates a spark, but as it is always emerged in fuel, it cannot ignite. The above diagram illistrates how the fuel is pumped to the injectors.

Fuel injector oscilloscope pattern