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Blown EFI fuse - comon cause??? Help

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Old 08-14-11, 08:40 PM
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91ls400own
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Default Blown EFI fuse - comon cause??? Help

Please help me. What can cause the EFI fuse to blow as soon as the key is turned??? There must be some obvious common causes...what are they??
ie: Bad fuel pump??? (Could that be one??)
Thanks
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Old 08-14-11, 08:42 PM
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a short .
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Old 08-14-11, 10:13 PM
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Originally Posted by PureDrifter View Post
a short .
Really?? Gee whiz who would have thunk!!

Where most likely is what I need re: good chance fuel pump???
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Old 08-15-11, 12:30 AM
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if the fuel pump SHORTED OUT you'd likely be asking us about the price of a new LS...
you know, given that it's in gas tank and all...

as i've said forever, all electrical troubleshooting on the 1LS starts with http://www.lexls.com/tutorials/lighting/bulbout.html

then you start hunting through everything else. the EFI fuse controls a LOT more than the fuel pump (given you should if i recall correctly have a separate fuse for that...)
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Old 08-15-11, 12:49 PM
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The 20A EFI fuse supplies power to the starter relay, headlight relay and the EFI main relay, the EFI relay then routes the supply to the circuit opening relay which in turn supplies further circuits.
You need electrical diagnostic skills and a methodical approach to isolate all the individual circuits connected to this fuse until you find the one that is causing the fuse to blow.
The 1st thing you need is a wiring diagram and of cause the ability to read and understand it along with a digital multmeter, if you do not have these skills take it to some one who does and get them to fix it.
As a starter pull out the EFI relay,replace the fuse and see if it blows, don't be tempted to put a bigger fuse in there or you could end up with burnt wiring or even a fire!
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Old 04-14-16, 05:06 PM
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Originally Posted by steve2006 View Post
The 20A EFI fuse supplies power to the starter relay, headlight relay and the EFI main relay, the EFI relay then routes the supply to the circuit opening relay which in turn supplies further circuits.
You need electrical diagnostic skills and a methodical approach to isolate all the individual circuits connected to this fuse until you find the one that is causing the fuse to blow.
The 1st thing you need is a wiring diagram and of cause the ability to read and understand it along with a digital multmeter, if you do not have these skills take it to some one who does and get them to fix it.
As a starter pull out the EFI relay,replace the fuse and see if it blows, don't be tempted to put a bigger fuse in there or you could end up with burnt wiring or even a fire!
So I took out the efi relay and the fuse doesn't blow... Now what??
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Old 04-14-16, 08:52 PM
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Has anything electrical been added to the car lately? Is it all factory stock? Was the problem all of the sudden or where there symptoms days before? Anyone do any work on the car?
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Old 04-15-16, 03:24 AM
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locked due to 5 year old+ thread.
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