Fuel pump relay

Tiny
DANIYALKZA
  • MEMBER
  • 2008 HYUNDAI COUPE
  • 2.7L
  • V6
  • 2WD
  • AUTOMATIC
  • 77,000 MILES
Hi, I have a weird problem with my fuel pump. When I pull out fuel pump relay the engine keeps running and does not shut off. Is it normal? Also, I can start and run engine without fuel pump relay in place. I have rewired the wire that goes from fuel pump relay to the fuel pump but that doesn't solved the problem.
Do you
have the same problem?
Yes
No
Saturday, January 2nd, 2021 AT 3:21 PM

3 Replies

Tiny
KASEKENNY
  • EXPERT
Is there any history to this? Meaning has anyone made any repairs other then you rewiring this? This is not normal. The only way the fuel pump can get voltage to turn on is if this has been jumped or there is a short to voltage. The way to test this is go to the pump and check for voltage with the key off and on. There should only be voltage when the key is on. Clearly if it starts and runs then it has power when the key is on but we need to make sure if someone ran a wire to it to bypass the relay that it is not on all the time. This is a safety issue because you clearly don't want your fuel system pressurized all the time.

https://www.2carpros.com/articles/how-to-check-wiring

What I suspect is someone has run a new wire to this and that is why you are getting voltage even when the relay is out. As long as there is only voltage there when the key is on, then it is okay. However, if this is the case, I bet there is an issue with the control side of the relay and the PCM is not energizing it and instead of replacing the PCM, they just hard wired it to a wire that is only on when the key is on. This is pretty common but eliminates the relay which can cause confusion for those that are not aware of it.

Let me know if this makes sense. Thanks
Was this
answer
helpful?
Yes
No
+1
Sunday, January 3rd, 2021 AT 6:12 PM
Tiny
DANIYALKZA
  • MEMBER
Thank you for your comment.I have checked fuel pump voltage and when key is off there is no voltage so I don't think it's jumped. This problem occured about 2 years ago and getting worst since. I have a acceleration problem too because of this and from all diagnostic checks that I have done I am sure the problem is just this. I think its short to something but how can I find where? I'm thinking about rewiring fuel pump with new wires and put fuel pump out of relay box because the wiring of relay box is old and complicated. Do you think it's good idea?If not how can I find the short?
Was this
answer
helpful?
Yes
No
Sunday, January 3rd, 2021 AT 11:42 PM
Tiny
KASEKENNY
  • EXPERT
I think that is exactly what you should do. I would just access the power wire from the relay at the bottom of the fuse box and run it directly to the fuel pump. This would eliminate any other possible wiring issue. Just cut the wire and connect the new wire to the connector side of each end. I attached a diagram below where I illustrated this.
Was this
answer
helpful?
Yes
No
+1
Monday, January 4th, 2021 AT 7:01 PM

Please login or register to post a reply.

Sponsored links