Injectors
Above is an injector pattern, what you can see from left to right is first the supply voltage then the voltage drops to almost 0V as the ECU grounds the circuit actuating the injector, the length of time the voltage is at 0V is how long fuel is being injected. You then have a voltage spike of about 35V because as the injector is turned off the collapsing magnetic field causes a "back EMF". If there was a short or break in the power supply the voltage would stay at 0V and if there was a break in the ground circuit or if the ECU is not earthing the voltage will stay at the supply voltage. If the injector has an internal short there will be a volt drop of the supply voltage across it.
An eaiser way to tell if an injector is actuating is to simply listen to it by either using a stethoscope a vacuum tube or put a screwdriver against it and put your ear to the other end of the screwdriver. You should be able to hear a clear and regular click.
When I waas testing the injectors on the 4AFE engine I got a 14.14 supply voltage for all four of the injectors, this is because they all share the same supply. By back probing the injectors I hocked up a multimeter so I could see if they were operating correctly, at idle all four injectors had a duty cycle of 96.5% duty cycle means how long they are operated for as a percentage of the time, but because the injectors are ground triggered the 96.5% actually represents how long they are inactive. Also at idle I measured the HZ rating and it was 11 for all four. HZ means how many times per second it's being fired i.e. each injector is being fired 11 times per second. I then revved the engine to find out what these went up to under acceleration the duty cycle maxed out at 85% and the HZ was 41. with these readings I can work out the width of each injector pulse with the calculation mS=(Duty cycle/100)/frequency so for at idle (3.5/100)/11=0.00318mS each time it fires and under acceleration (15/100)/41=0.0015mS
I believe this is a good way to test injectors because you don't need to remove them from the engine, unfortunately it cannot tell you if the injector is blocked.
An eaiser way to tell if an injector is actuating is to simply listen to it by either using a stethoscope a vacuum tube or put a screwdriver against it and put your ear to the other end of the screwdriver. You should be able to hear a clear and regular click.
When I waas testing the injectors on the 4AFE engine I got a 14.14 supply voltage for all four of the injectors, this is because they all share the same supply. By back probing the injectors I hocked up a multimeter so I could see if they were operating correctly, at idle all four injectors had a duty cycle of 96.5% duty cycle means how long they are operated for as a percentage of the time, but because the injectors are ground triggered the 96.5% actually represents how long they are inactive. Also at idle I measured the HZ rating and it was 11 for all four. HZ means how many times per second it's being fired i.e. each injector is being fired 11 times per second. I then revved the engine to find out what these went up to under acceleration the duty cycle maxed out at 85% and the HZ was 41. with these readings I can work out the width of each injector pulse with the calculation mS=(Duty cycle/100)/frequency so for at idle (3.5/100)/11=0.00318mS each time it fires and under acceleration (15/100)/41=0.0015mS
I believe this is a good way to test injectors because you don't need to remove them from the engine, unfortunately it cannot tell you if the injector is blocked.
Ignition Coils
Coil# 1 No ...............0209..................... Coil #2 No ..............Lucas...........................
Coil# 1 Voltage ...............12V..................... Coil# 2 Voltage ..................................
Coil #1 Primary ................3................... Coil #2 Primary ..................................
Coil# 1 Secondary .............9.1K........... Coil #2 Secondary .............................
R3=0.9= (12/3)-3.1 (3.1 is the resistance of the coil primary windings and 3 is the rating of the transistor)
this is a very simple circuit so there were no issues with constructing it and working out the values other than the internet being a bit of a punk and it took me a little while to find the data sheet.
