EFI fuse keeps blowing

Tiny
ANN MARIE KELLY
  • MEMBER
  • 2005 SCION TC
  • 2.4L
  • 4 CYL
  • FWD
  • MANUAL
  • 113,000 MILES
The other night driving home on the highway it shutoff and would not start. Once I got the car home I found that EFI fuse was blown. When I go to replace the fuse it blows before I can even get it plugged in and there is no key in the ignition. I then proceeded to check wiring for possible short and could not find anything. I then pulled the EFI relay and tried plugging in fuse and it did not blow. I also unplugged all the injectors plugged relay back in then tried to put fuse in and it blew. So is it a bad relay that is causing this?
Thursday, April 6th, 2017 AT 4:12 PM

6 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
It might be try switching relay with a known good relay then see if it blows. If it does then just replace the relay, but if it continues then the wiring may be shorting against block or body if that harness lies against it.
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Thursday, April 6th, 2017 AT 4:36 PM
Tiny
ANN MARIE KELLY
  • MEMBER
  • 3 POSTS
Thank you I will give that a try.
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Friday, April 7th, 2017 AT 7:59 AM
Tiny
CARADIODOC
  • MECHANIC
  • 34,206 POSTS
Here's a trick to go with HMAC300's suggestion. Replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a 12 volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it's not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out
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+2
Saturday, April 8th, 2017 AT 11:05 PM
Tiny
ANN MARIE KELLY
  • MEMBER
  • 3 POSTS
Thanks for the info that seems a nifty trick. Car is at garage now. Once I find out what it was ill be sure to post it.
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Monday, April 10th, 2017 AT 10:58 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,235 POSTS
Yep yep Caradiodoc is one of our best mechanics!

Please use 2CarPros anytime, we are here to help and tell a friend.

Best, Ken
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Wednesday, April 12th, 2017 AT 6:49 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,206 POSTS
Thanks, Ken. I DO have a lot of people fooled!
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Wednesday, April 12th, 2017 AT 7:40 PM

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