Injectors are NOT firing

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Aug 20, 2019 | 11:25 AM
  #1  
I just installed a set of injectors from South Bay as one of the stock ones were leaking fuel. Now the Injectors are NOT firing.. the mechanic thinks it maybe electrical... thoughts?
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Aug 20, 2019 | 11:39 AM
  #2  
Re: Injectors are NOT firing
He "thinks"?!? Get a new mechanic. This should be easy to track down. Check for power to the injectors. Check for injector pulse from the ECM. If you get nothing there check that the ECM is getting a distributor reference pulse. If it is then check for power supply and ground to the ECM. If you have all that the ECM is bad.

GD
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Aug 20, 2019 | 12:05 PM
  #3  
Re: Injectors are NOT firing
icm or could be vats
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Aug 20, 2019 | 12:33 PM
  #4  
Re: Injectors are NOT firing
Quote: icm or could be vats
icm is pretty inexpensive.. I will pick one up to be on the safe side.. better then the ecm for sure.. what was cause the Vats system to act up?
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Aug 20, 2019 | 12:48 PM
  #5  
Re: Injectors are NOT firing
A bad key reader would cause vats to act up.
to test I’m assuming this is a 1227730 ecm. There is a blue wire in cavity f10.
you can turn the key to the accessory position. If it’s working correctly you will have 2.5v on this blue wire.

https://tpiparts.net/1227730_pinout_diagram

if you have loss of spark as well it’s more than likely the icm or pickup coil. Could be a wiring issue heat can cause damage to the four wires that connect to the icm that run to the ecm.
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Aug 20, 2019 | 12:48 PM
  #6  
Re: Injectors are NOT firing
Quote: icm is pretty inexpensive.. I will pick one up to be on the safe side.. better then the ecm for sure.. what was cause the Vats system to act up?
DO NOT troubleshoot with Visa. Test, Verify, Replace. Don't be a parts changer.

GD
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Aug 20, 2019 | 02:23 PM
  #7  
Re: Injectors are NOT firing
What they said, its possible the mechanic blew the fuse to the injectors during the install?
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Aug 27, 2019 | 11:59 AM
  #8  
Re: Injectors are NOT firing
fuses are good... there IS power goin to the injectors.. but the pulse that tells the injectors to fire is NOT working...
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Aug 27, 2019 | 12:08 PM
  #9  
Re: Injectors are NOT firing
Did you verify no pulse with noid lights? Do you have spark? If they were firing before replacing I would suspect a connection was missed or one or more injector could be bad (even with quality parts it can happen). I would ohm each in injector.

The wiring is pretty simple I would ohm each wire back to the ECU connection as my first step of the injectors ohm out correctly. Then test the icm and also make sure the rotor is turning in the distributor if no spark.
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Aug 27, 2019 | 12:43 PM
  #10  
Re: Injectors are NOT firing
yeah the mechanic has a the light to check so I'm assuming he will do that this week. I think hes gonna concentrate on the ECM first as its a simpler process.
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Aug 28, 2019 | 10:18 AM
  #11  
Re: Injectors are NOT firing
Quote: yeah the mechanic has a the light to check so I'm assuming he will do that this week. I think hes gonna concentrate on the ECM first as its a simpler process.
I think you need a new mechanic. Chances are that swapping the ECM is not going to solve the issue. He needs to check reference pulse and power/ground to the ECM before he determines it's bad.

Calling out an ECM is NOT a simple process. It requires a lot of testing and verification.

GD
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Aug 28, 2019 | 10:34 AM
  #12  
Re: Injectors are NOT firing
yea... I hate to say it but I would be finding a new mechanic, the ECU was working before the new injectors so unless he hooked the battery up backwards or did something else that he thinks fried the ECU there is no real reason to suspect it.
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Aug 28, 2019 | 12:10 PM
  #13  
Re: Injectors are NOT firing
Was post 5 verified ?
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Aug 28, 2019 | 12:21 PM
  #14  
Re: Injectors are NOT firing
Do verify VATS.

Someyear cars have an inline ECU fuse beside the battery, and a wiring block behind it. If the mechanic fully removed the battery this could be effected.

My gut says he missed a connection or one went bad after unplugging.

Have you verified fuel pressure?
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Nov 19, 2019 | 10:40 PM
  #15  
Re: Injectors are NOT firing


Car has been repaired.. thanks for all the help guys.. the ECM was the issue.. bought a reman acdelco from rockauto.com and the injectors now fire correctly... i seem to have lost a vacuum hose and im not sure where it went, wat hose it was or where it goes but i assume its the reason for the rough idle and SES light.

pics of what im talking about

Quote: I think you need a new mechanic. Chances are that swapping the ECM is not going to solve the issue. He needs to check reference pulse and power/ground to the ECM before he determines it's bad.

Calling out an ECM is NOT a simple process. It requires a lot of testing and verification.

GD

it was indeed the ECM..thanks to all that helped.
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Nov 19, 2019 | 10:53 PM
  #16  
Re: Injectors are NOT firing
Quote: I think you need a new mechanic. Chances are that swapping the ECM is not going to solve the issue. He needs to check reference pulse and power/ground to the ECM before he determines it's bad.

Calling out an ECM is NOT a simple process. It requires a lot of testing and verification.

GD

it was indeed the ECM..thanks to all that helped.
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Nov 19, 2019 | 11:07 PM
  #17  
Re: Injectors are NOT firing
You have 3 vacuum connections
1 for the hvac, 1 for map and one for fuel pressure regulator.
looks kind the regulator one might be missing.
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Nov 20, 2019 | 12:51 AM
  #18  
Re: Injectors are NOT firing
Quote: You have 3 vacuum connections
1 for the hvac, 1 for map and one for fuel pressure regulator.
looks kind the regulator one might be missing.

ok.. where can i find a hose.. and where does it got from the runners lol.
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Nov 20, 2019 | 11:23 AM
  #19  
Re: Injectors are NOT firing
Iirc 5/32 vacuum hose. Goes from the vacuum nipple to the pressure regulator.
if that one is already hooked up it’s for hvac and comes from the wiring loom passengers side.
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Dec 15, 2019 | 09:47 PM
  #20  
Re: Injectors are NOT firing
Quote: Iirc 5/32 vacuum hose. Goes from the vacuum nipple to the pressure regulator.
if that one is already hooked up it’s for hvac and comes from the wiring loom passengers side.
would that cause the car to run bad? ses light?
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