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08-25-2020, 05:39 PM
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#1 |
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Senior Member
 
Join Date: Jun 2015
Location: Atlanta, GA.
Posts: 737
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Fuel pump cut off
I just saw a post in the general section that got me thinking. Does the LS PCM (specifically 2003 5.3 in my case) have an internal cut off to the fuel pump should the engine stop running? (like in a crash or roll over?)
I did not put one in but just wondering if I should?
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Jay Gesner Atlanta, GA 1985 C10 Long Bed 4X2 LS 5.3, 4L60E Father/Daughter Project |
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08-25-2020, 06:50 PM
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#2 |
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Registered User
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,119
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Re: Fuel pump cut off
The fuel pump will shut off as soon as the PCM no longer sees any engine RPM, so if the engine dies, the pump won't stay running.
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My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
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08-25-2020, 08:41 PM
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#3 |
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Registered User
Join Date: Jun 2015
Location: Carlos MN
Posts: 2,132
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Re: Fuel pump cut off
I believe the Fox body Mustangs had some type of roll over device in the trunk area of the car.
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08-26-2020, 11:20 PM
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#4 | |
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Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: Fuel pump cut off
Quote:
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08-27-2020, 02:42 AM
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#5 |
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Registered User
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,119
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Re: Fuel pump cut off
And when someone bumps your car in a parking lot and trips it, it will be the last thing you think to check, been there!! LOL
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
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08-27-2020, 10:54 AM
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#6 |
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Senior Member
Join Date: Jun 2015
Location: Atlanta, GA.
Posts: 737
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Re: Fuel pump cut off
Cool! Thank you very much!
I was hoping that was the case as I didn't want to rewire my set up. Y'all rock! 
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Jay Gesner Atlanta, GA 1985 C10 Long Bed 4X2 LS 5.3, 4L60E Father/Daughter Project |
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08-30-2020, 10:13 AM
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#7 |
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Registered User
Join Date: Feb 2012
Location: Ruskin Florida
Posts: 4,566
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Re: Fuel pump cut off
There is a fellow on here that got a great deal on an engine because it was in a rollover and kept running long enough to wipe out some lower end bearings. While we never "plan" on getting in an accident, we should plan for them. I have a rollover switch on my 4x4 going to the oil pressure which shuts off the fuel pump when no oil pressure is present. I totaled that truck once and did not roll but I am glad it was there.
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70 swb 4x4 406sbc 700r4 203/205 d60/14blt locker yadda yadda http://67-72chevytrucks.com/vboard/s...88#post6935688 Yeller 72 Blazer 2wd conversion project "No Daggum Money" http://67-72chevytrucks.com/vboard/s...d.php?t=550804 LS1-T56 3.73 LSD super budget build Blanco-2014 Sierra SWB https://67-72chevytrucks.com/vboard/...d.php?t=810350 |
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08-30-2020, 07:45 PM
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#8 |
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Senior Member
Join Date: Jun 2015
Location: Atlanta, GA.
Posts: 737
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Re: Fuel pump cut off
Is there any way to test the pcm to see if it will cut off if engine quits running?
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Jay Gesner Atlanta, GA 1985 C10 Long Bed 4X2 LS 5.3, 4L60E Father/Daughter Project |
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08-30-2020, 09:27 PM
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#9 |
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Registered User
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,119
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Re: Fuel pump cut off
When you turn the key on and don't start the engine, and the fuel pump runs for 3 seconds or so, the PCM is shutting off the fuel pump. I have never seen one fail ad just keep the pump on all the time. Other than that, you would have to kill the engine somehow to prove it to yourself, so blocking off all the air to the throttle body should do it if you're so inclined....
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
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