Injectors will not fire!
04-16-2011, 07:38 PM
#1
Injectors will not fire! I tested EVERY possible thing that could be wrong:
The injectors have 12V,
the fuel rail has 60 psi,
car runs on starter fluid,
injectors are NOT firing when cranking the car,
the injectors work with a constant 12V power source,
the crank position sensor wires work and are not shorted out,
everything is working except the injectors.
Does anyone have ANY Idea why the injectors not firing?
The injectors have 12V,
the fuel rail has 60 psi,
car runs on starter fluid,
injectors are NOT firing when cranking the car,
the injectors work with a constant 12V power source,
the crank position sensor wires work and are not shorted out,
everything is working except the injectors.
Does anyone have ANY Idea why the injectors not firing?
04-16-2011, 09:10 PM
#2
was the wiring altered?
sounds like one of two things
you do not have 12v at the injectors with the key in the start position. I assume you are seeing 12V at the injectors with the key in the on position
or the ECM is not providing a ground to activate each injector
sounds like one of two things
you do not have 12v at the injectors with the key in the start position. I assume you are seeing 12V at the injectors with the key in the on position
or the ECM is not providing a ground to activate each injector
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hm562 (06-04-2023)
04-16-2011, 10:26 PM
#4
Do you have 12V when cranking or when the key is held in the start position?
It is possible to have 12V at the injectors with the key on and not have 12V with the key in the start/cranking position. Those key positions are 2 different voltage sources.
The injectors have 12V supplied to them and the ECU provides the ground to turn on each injector. A cause for this (no ground) could be a bad ECU.
It is possible to have 12V at the injectors with the key on and not have 12V with the key in the start/cranking position. Those key positions are 2 different voltage sources.
The injectors have 12V supplied to them and the ECU provides the ground to turn on each injector. A cause for this (no ground) could be a bad ECU.
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hm562 (06-04-2023)
04-17-2011, 10:35 PM
#6
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Give us some history on the vehicle... Which PCM and are you running? You are using a L92 engine, correct? Had the engine ran before up until you swapped the intake manifold?
You say that your crank position sensor is working well, the injectors drivers receive their signal from the camshaft sensor. Confirm that the CAMSHAFT position sensor had 12v and a ground, as well as continuity from the sensor to the PCM itself.
Also how are you checking the ground from the injector driver (pulsewidth)? Are you using noid lights? If you are using a multimeter or test light, the signal is too fast to be caught on a multimeter though a test light will pick it up and will be faint flicker.
You say that your crank position sensor is working well, the injectors drivers receive their signal from the camshaft sensor. Confirm that the CAMSHAFT position sensor had 12v and a ground, as well as continuity from the sensor to the PCM itself.
Also how are you checking the ground from the injector driver (pulsewidth)? Are you using noid lights? If you are using a multimeter or test light, the signal is too fast to be caught on a multimeter though a test light will pick it up and will be faint flicker.
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04-18-2011, 07:10 PM
#8
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Did the engine run before you swap the intake?
How are you checking the ground signal? With a test light? You can buy noids lights at the parts store though they are expensive. See if you can borrow a set from someone.
How are you checking the ground signal? With a test light? You can buy noids lights at the parts store though they are expensive. See if you can borrow a set from someone.
04-18-2011, 07:35 PM
#9
I was gonna say...the ECU probably supplies battery voltage until it switches to ground to fire the injector(i.e. battery voltage to both pins)....someone correct me if I'm wrong. So the 12V your measuring may be FROM the ECU not from the power supply. Disconnect the injector connector and check boths pins with key on.
05-16-2011, 06:46 AM
#12
Anyone that cares....it ended up being the VATS wasn't completely turned off. HP Tuners (2 different versions) said it was off but when I sent it to Speartech (props to John) they found that it wasn't completely turned off. Do they use Tech II (2)? Anyway, he turned off VATS and the car started right up. A month of trouble shooting and it was just a click of the mouse.
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Frank Guerra (10-02-2021)
10-07-2012, 04:02 PM
#13
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fastcayman Anyone that cares....it ended up being the VATS wasn't completely turned off. HP Tuners (2 different versions) said it was off but when I sent it to Speartech (props to John) they found that it wasn't completely turned off. Do they use Tech II (2)? Anyway, he turned off VATS and the car started right up. A month of trouble shooting and it was just a click of the mouse.
Hi Guys,
Further to your findings, I also had a similar problem. the fuel pump was changed, all grounds checked, swapped the computer, but injectors would not fire. so I lifted the intake, replaced the camsensor and also changed out the injectors and bingo.
My theory, these cars are 12 to fourteen yrs old. and yet a lot of them are still running the original fuel pump and injectors. if the sit unsued for a while chances are somthing will likely quit. I'm pretty sure the injectors were stuck so just my farthen worth.
hope it helps,
Hansen
08-28-2016, 12:26 PM
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Need help Engine is 1999 5.3 with 4L60e Been done for 6 years Has spark, good fuel pressure and fuel pump is working It just started this issue It runs and they it won't start it's like it's getting heat soaked. Now the injectors aren't pulsing. Just check all the grounds and power in the harness all ok
on the injector with the key on we have 12v on one side but not the other
We just drove and and started it and it set for 10 min and won't start again
on the injector with the key on we have 12v on one side but not the other
We just drove and and started it and it set for 10 min and won't start again
08-28-2016, 12:34 PM
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Need help Engine is 1999 5.3 with 4L60e Been done for 6 years Has spark, good fuel pressure and fuel pump is working It just started this issue It runs and they it won't start it's like it's getting heat soaked. Now the injectors aren't pulsing. Just check all the grounds and power in the harness all ok
on the injector with the key on we have 12v on one side but not the other
We just drove and and started it and it set for 10 min and won't start again
on the injector with the key on we have 12v on one side but not the other
We just drove and and started it and it set for 10 min and won't start again
