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Discussion Starter · #1 ·
My 08 g8 3.6 shut off on the highway, and won’t run. I checked all fuel pump fuses and relays. They all checked out good. I can spray starting fluid and it will run til I stop spraying. Any idea on what my problem may be? Thanks in advance.
 

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Since the car only runs while spraying starter fluid, then it's not getting sufficient fuel. Current mileage? Fuse F12 in the rear compartment (trunk) as well as relay R12 in the instrument panel compartment power the fuel pump. Do you have a circuit tester? If not, try swapping the R12 relay with another and see if anything changes. When the ignition is turn to on (not run) without attempting to start the vehicle, can you hear the fuel pump "prime" the injectors? It should run for a few seconds before shutting off.
 

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Discussion Starter · #3 ·
Since the car only runs while spraying starter fluid, then it's not getting sufficient fuel. Current mileage? Fuse F12 in the rear compartment (trunk) as well as relay R12 in the instrument panel compartment power the fuel pump. Do you have a circuit tester? If not, try swapping the R12 relay with another and see if anything changes. When the ignition is turn to on (not run) without attempting to start the vehicle, can you hear the fuel pump "prime" the injectors? It should run for a few seconds before shutting off.
Already checked and swapped out the relay as well. Going to check power at the fuel pump next.
 

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If you can get an ear near, or a device that would help transmit sound to your ear, you should/would hear that pump run for 2 seconds at ignition turn on. That's the way the system works "if" engine cranking does not happen. Once the engine detects rotation, the fuel pump would be commanded to run all the time until engine shutdown takes place. If "no" pump running sound is detected, an your sure the pump relay an pump power fuse is not the problem, the hard work starts. Gaining access to the pump electrical connector gets very labor intensive (unless the car has been modified with the installation of the fuel tank pump/sensor access plate under the rear seat cushion.
 

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He sure could, if he has a hose an gauge setup that will depress the valve core an thread up correctly Or remove the valve core an attach a gauge an hose section that will thread onto the (now open) fuel rail correctly
 

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Checking fuel pressure would be easier versus power at the pump. If the fuel pump is found to be inoperative, might be worthwhile to install an access cover.
 

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Discussion Starter · #9 ·
If you can get an ear near, or a device that would help transmit sound to your ear, you should/would hear that pump run for 2 seconds at ignition turn on. That's the way the system works "if" engine cranking does not happen. Once the engine detects rotation, the fuel pump would be commanded to run all the time until engine shutdown takes place. If "no" pump running sound is detected, an your sure the pump relay an pump power fuse is not the problem, the hard work starts. Gaining access to the pump electrical connector gets very labor intensive (unless the car has been modified with the installation of the fuel tank pump/sensor access plate under the rear seat cushion.
All fuses and relays checked out ok, I’m going to cut out the fuel pump access hole under the rear seat. Thank you for your help.
 

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I haven’t done that yet, going to look for access to the fuel rail to check for fuel pressure.
Sure but you have to CAREFULLY cut a big hole first. Although a great idea, seems like a lot of effort just to confirm fuel pressure. If there's no pressure in the rail, then yeah.
 

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Discussion Starter · #13 ·
Sure but you have to CAREFULLY cut a big hole first. Although a great idea, seems like a lot of effort just to confirm fuel pressure. If there's no pressure in the rail, then yeah.
Thanks for the advise, guess better to variety through the fuel rail before butting out the hole.
 

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Aren't there two fuel pumps, due to the "saddle" style tank? One to feed the engine and one to move fuel from one side of the tank to the other side?
 
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