Crank, no start I have replaced the BCM in the trunk?

Tiny
DREWCIFER419
  • MEMBER
  • 2011 CHEVROLET MALIBU
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
Crank, no start. I've replaced the BCM in the trunk, replaced the fuel pump relay, replaced one of the camshaft position sensors. Not getting any power to fuel pump relay so fuel pump isn't priming. No clicking of fuel pump relay when ignition is on. Unsure if it's a typical GM/Chevy wiring issue, the ECM, or the crankshaft position sensor. The only testers I have is a basic test light and a multimeter that I have no idea how to test anything with. I can turn a wrench and that's about it. Any help would be greatly appreciated.
Wednesday, September 25th, 2024 AT 4:10 PM

8 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,149 POSTS
So, the PCM will not turn the fuel pump on if the computer does not see air flow through the MAF sensor, please go over this video to see what I am talking about, and it shows you the easy stuff to guide us in the right direction.

https://youtu.be/lXLJbuAZ4CE?si=JgUdpt9OEs6lh4na

Please go over this guide and get back to us.
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Thursday, September 26th, 2024 AT 2:09 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

Hang in there. We'll figure it out. Here is what I need you to try as a test: You will need a short jumper wire.

If you look at the attached pic below, it shows the fuel pump relay schematic. What I need you to do is remove the relay and identify the connector pin numbers on the relay itself. Locate pins 30 and 87 on the relay. Then determine which connectors they plug into in the relay box.

Take the jumper wire and jump the two pins. When you do this, the fuel pump should turn on.

Let me know what happens.

Joe

See pics below.
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Thursday, September 26th, 2024 AT 2:47 PM
Tiny
DREWCIFER419
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Now just got to find where to get a jumper wire from.
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Thursday, September 26th, 2024 AT 5:56 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

You could even use a paper clip. However, it could get hot so make sure to protect your hands. Also, make sure not to run it too long like that.

Let me know.

Joe
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Thursday, September 26th, 2024 AT 6:08 PM
Tiny
DREWCIFER419
  • MEMBER
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Okay, so I used a paperclip to try to jump the connection between 30 and 87 and still got nothing. The fuel pump still didn't turn on. Does that signify that I'm not getting ground to the relay? Or at least a broken connection somewhere?
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Friday, September 27th, 2024 AT 8:34 AM
Tiny
KEN L
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  • 54,149 POSTS
Yes, that is correct, or the fuel pump is bad which is common, when you jump the paper clip see if you have power to the gray wire at the fuel tank which goes to the fuel pump.

This guide can help:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here is how to change the fuel pump out in case you need it. Check out the images (below). Please let us know what happens.

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Friday, September 27th, 2024 AT 11:05 AM
Tiny
DREWCIFER419
  • MEMBER
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Just a quick update. I haven't been able to go out and work on it much. It's been raining the past few days, and the car is sitting outside. I want to check to see if there's a broken connection in any of the wires but have no idea how to find out where they go. Based on the research I've done, I looks like pin 86 is the ground but have no idea where that runs to but know it's labeled G302. Pin 85 is the I/O high-side drive switch, which I'm assuming is the one that runs for two seconds to prime when cranked. Pin 30 is connected to the fuel pump fuse, which I know the fuse is working from testing it with a test light. Pin 87 goes to the fuel pump and sender assembly which has a ground (G301) and have no idea where that would run to. Is there a chance that it could be the ignition switch, CKS, or ECM and not a wiring issue? I certainly don't want to just throw money into it with hopes of it temporarily fixing the issue for it to come back. Any help would be greatly appreciated. Thank you all for your help so far.
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Wednesday, October 2nd, 2024 AT 1:28 AM
Tiny
KEN L
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Did you swap out the fuel pump relay and check the fuses, here is a guide to ehlp and I have included the engine, fuel pump, and fuel pump relay wiring diagrams so you can do some testing of the connections and see how the system works.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know what happens.
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Wednesday, October 2nd, 2024 AT 10:57 AM

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