This is a crude test to see if they are being actuated and are opening. Tested result is OK
Can you get to all the injectors? Yes
Comments: injecters sound like they are working fine, no thumping sound, fast tapping sound is produced
- when i checked the voltage to the injectors at Key On. making sure i have the battery voltage to the injectors so they can work. I Recorded the battery voltage witch was 14.23v
Record voltage at each injector you can get to by back probing. Be careful to not puncture or damage wiring.
- Below is the primery waveforms of the injectors 1, 2, 3, 4, i the first one it shows what the reading means.
With engine idling, watch injector firing by using a multi-meter set to read % (duty cycle). Record the readings for each cylinder at idle in the boxes below.
With the multi-meter still set to read % (duty cycle), accelerate the engine with short, fast throttle openings (don’t over-rev or damage the engine please), and note in the boxes below the maximum % reading
you can get on the multi-meter: note the RPM.
Set the multi-meter to read Hz, and with the engine idling, record the readings for each cylinder in the boxes below:
With the multi-meter still set to read Hz, increase the engine RPM (don’t damage the engine), and watch how the Hz changes. Record your highest reading in the boxes below: Take the readings at the same RPM
as you used in question 5.
Using this formula calculate the pulse width of each injector both at idle and when the engine is revved up
“Pulse width ms= (% Duty cycle x100)/Frequency”
Show your calculations
CALCULATED TIME AT IDLE>
Cyl:#1: (97.8/100) /7.00= 0.13ms
Cly#2: (97.9/100) /6.93=0.155ms
Cly#3: (97.8/100)/6.83=0.14ms
Cly#4: (97.8/100)/6.81=0.14ms
CLCULATED TIME WHEN REvVED>
Cly#1: (89.7/100)/24.75=0.03ms
Cly#2: (89.6/100)/30.90=0.02ms
Cly#3: (87.9/100)24.30=0.03ms
Cly#4: (81.6/100)29.08=0.02ms
After back probing to test every injector i got the readings above wich are ecceptable.
When at idle the voltage suits the 0.13ms fuel injection speed.
When the RPM is high the speed becomes higher for the fuel injection.
This happens becouse the throttle opens letting the TPS sensor tell the ECU it needs more fule to pull ahevier load , this makes the injecters fire faster.
