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Discussion Starter · #1 ·
Hey guys 3rd day of the most stressful problem ever ,my longtube headers and street tuned 2009 cts V left me stranded wouldn’t hear fuel pump turn on , checked fuses turned out to be FSCM fuse blown , reading code u0109 ( lost connection to fuel pump) on the snap on scanner . After swapping the fuse went on a 5 min drive and boom stranded again , got a hold of 30a fuses at gas station took me 6 of them to get home . Checked all wires from FSCM to fuse box and no noticable problems in the wires , has anybody had this problem ? Next step would be taking it to a shop but I’m hoping the CTSV community can come together and help me out on this one . Any tips or suggestions would be much appreciated thanks !!!
 

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2011 CTSV Coupe M BLK LSX376-B15
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Hey guys 3rd day of the most stressful problem ever ,my longtube headers and street tuned 2009 cts V left me stranded wouldn’t hear fuel pump turn on , checked fuses turned out to be FSCM fuse blown , reading code u0109 ( lost connection to fuel pump) on the snap on scanner . After swapping the fuse went on a 5 min drive and boom stranded again , got a hold of 30a fuses at gas station took me 6 of them to get home . Checked all wires from FSCM to fuse box and no noticable problems in the wires , has anybody had this problem ? Next step would be taking it to a shop but I’m hoping the CTSV community can come together and help me out on this one . Any tips or suggestions would be much appreciated thanks !!!
If you have had a fuel pump upgrade or BAP, may consider checking the wiring in those areas for damage.
 

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Also, while rare, pump motors do fail, and some of those failure mechanisms can result in higher current draw. So no issue with the wiring, you probably need a new pump.

Did you ever run the tank really low or completely dry? The pump is electric, but it runs submerged in fuel which acts as a coolant for the motor. I dimly remember that operating the car with very low fuel levels could leave the pump motor exposed allowing it to overheat, leading to failure. But note, this might have been some other GM product that I've owned. "Dimly remember"...
 

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Discussion Starter · #4 ·
Also, while rare, pump motors do fail, and some of those failure mechanisms can result in higher current draw. So no issue with the wiring, you probably need a new pump.

Did you ever run the tank really low or completely dry? The pump is electric, but it runs submerged in fuel which acts as a coolant for the motor. I dimly remember that operating the car with very low fuel levels could leave the pump motor exposed allowing it to overheat, leading to failure. But note, this might have been some other GM product that I've owned. "Dimly remember"...
Man it’s a 50% chance I tested the fuel pump with a buddy and it switched on fine but Mabye there is a chance it just isn’t working right anymore , just right now I checked all wiring again and no
Problems only thing is that positive battery wire kind of touches the negative battery post but it’s completely layered in electric tape , can it be that it’s creating a short thru it ? , next thing I was going to do was swap to FSMC itself , either that after studying gm vehicles from this year (Vs, Silverado’s , Tahoe, ) common problem thru those years a lot of people had to resort to swapping their fuse box as well 🤦🏽‍♂️ I’m going crazy lol

If you have had a fuel pump upgrade or BAP, may consider checking the wiring in those areas for damage.
I don’t see any BAP , I just purchased the vehicle also but I’m guessing it would be around the battery and it’s not , also stock fuel pumps

Also, while rare, pump motors do fail, and some of those failure mechanisms can result in higher current draw. So no issue with the wiring, you probably need a new pump.

Did you ever run the tank really low or completely dry? The pump is electric, but it runs submerged in fuel which acts as a coolant for the motor. I dimly remember that operating the car with very low fuel levels could leave the pump motor exposed allowing it to overheat, leading to failure. But note, this might have been some other GM product that I've owned. "Dimly remember"...
And I also did run the tank empty beofre this problem started , I ran it to the gas station after trying to switch it on , got there shut off that pumped gas then wouldn’t switch on and here we are now
 

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2011 CTSV Coupe M BLK LSX376-B15
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I don’t see any BAP , I just purchased the vehicle also but I’m guessing it would be around the battery and it’s not , also stock fuel pumps
Electrical is always a challenge, even for full time professionals. If you have some electrical experience and understanding then you could try your best to figure it out. Otherwise, these days there are mobile services, techs will come to your home with equipment for an hourly or job fee. Most of the time they are reasonable with pricing, I had a situation I called on one with positive results.

If you do have stock pumps, then accessing them for testing will be a challenge for sure. You could do a search on the site to learn more about that subject. (see attached)

But whatever you do, never install higher amp fuses to try and solve an electrical problem!
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Man it’s a 50% chance I tested the fuel pump with a buddy and it switched on fine but Mabye there is a chance it just isn’t working right anymore , just right now I checked all wiring again and no
Problems only thing is that positive battery wire kind of touches the negative battery post but it’s completely layered in electric tape , can it be that it’s creating a short thru it ? , next thing I was going to do was swap to FSMC itself , either that after studying gm vehicles from this year (Vs, Silverado’s , Tahoe, ) common problem thru those years a lot of people had to resort to swapping their fuse box as well 🤦🏽‍♂️ I’m going crazy lol

And I also did run the tank empty beofre this problem started , I ran it to the gas station after trying to switch it on , got there shut off that pumped gas then wouldn’t switch on and here we are now
No, it's not shorting if it's taped. If it was shorting, you'd see clear signs of melting/burning. A dead-short across the battery would result in unambiguous evidence of same.

I'm making a screwed-up squinty-eye face on the "did run the tank empty" comment :cautious:.

I'm thinking your pump is bad. Just because it pumps doesn't mean it's good. You need to find yourself a clamp-on Ammeter and see how many Amps it's pulling while it's running. Given that you replace the fuse and get a few minutes of driving before it pops again, I'd suggest you leave the meter on with the engine running and see if the current changes over time. A common failure mode in an overheated electric motor is "shorted windings". The magnet wire coil is only insulated with a coating of enamel (or Kapton or something similar that's really thin so you can get more turns of wire around the armature, you're not losing space to insulation). If it gets hot enough, it carbonizes or melts in spots and those spots become susceptible to short circuits. The motor, even immersed in gas, will get hotter the longer it runs. As it does, things start to move mechanically due to thermal expansion. A motor that starts just fine when its cool can suddenly start to draw more current once it warms up, if the winding insulation is damaged. The short circuit that causes the current to go up doesn't happen until heat makes things move enough to bring the shorted sections of the windings together.

You won't need to cut any holes in the car to measure the current draw of the pump. So do that before you decide the pump is bad and go through all the effort to gain access to it. :)
 

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Discussion Starter · #8 ·
No, it's not shorting if it's taped. If it was shorting, you'd see clear signs of melting/burning. A dead-short across the battery would result in unambiguous evidence of same.

I'm making a screwed-up squinty-eye face on the "did run the tank empty" comment :cautious:.

I'm thinking your pump is bad. Just because it pumps doesn't mean it's good. You need to find yourself a clamp-on Ammeter and see how many Amps it's pulling while it's running. Given that you replace the fuse and get a few minutes of driving before it pops again, I'd suggest you leave the meter on with the engine running and see if the current changes over time. A common failure mode in an overheated electric motor is "shorted windings". The magnet wire coil is only insulated with a coating of enamel (or Kapton or something similar that's really thin so you can get more turns of wire around the armature, you're not losing space to insulation). If it gets hot enough, it carbonizes or melts in spots and those spots become susceptible to short circuits. The motor, even immersed in gas, will get hotter the longer it runs. As it does, things start to move mechanically due to thermal expansion. A motor that starts just fine when its cool can suddenly start to draw more current once it warms up, if the winding insulation is damaged. The short circuit that causes the current to go up doesn't happen until heat makes things move enough to bring the shorted sections of the windings together.

You won't need to cut any holes in the car to measure the current draw of the pump. So do that before you decide the pump is bad and go through all the effort to gain access to it. :)
Will do man thank you so much for the insight I really appreciate it, not many people out there willing to help as much as u did sir , will update later this week :)
 
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