Sunday, 17 April 2011

fuel injectors

on car


used a multimeter to measure the resistance for the injectors against the given resistance spec. of the injectors
and pulsing/voltage at idle and when gently reved
also used a multi meter to measure the duty cycle of the injectors which was 100%
also used a logic probe  to measure injectors' pulsing,off the connection
from/to the ECU.


Resistance: 16.5




 Injector #1 …16.2…………….. Ω

Injector #2 …16.5…………….. Ω

Injector #3 …16.5…………….. Ω

Injector #4 …16.2…………….. Ω

I used the logic probe, connected to the ECU's connection to the injectors. I started the engine and the light was pulsing. When the engine was rev'd up the flickering was faster.this is because when the engines reving there alternator charges the battery with a bigger charge so the flickering is in response to the increased voltage.

I did the same test this time with a voltmeter. the red lead was on the injectors and the black lead was grounded. When engine was started the voltage was 14.2 V
When reving the voltage was 13.35 V. The increase is also attributed to battery charge increase as the injectors put out more fuel. As this a test of the fuel injectors an increase in voltage would then indicate that the injectors are working well.

Measuring Duty cycle: set the multi meter to dutycycle. When engine was started, the duty cycle was 100.5%.  Reving the engine the duty cycle was 100.3%

above,checking resistance of the fuel injectors.remove injectors caps and measure on the pins

average resistance of 16.5 ohms


injectors voltage 14.33 V at idle and 13.45 V at gentle rev

checking the duty cycle of the injectors:100%

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