Fuel pump not working

GUITON

MEMBER
2003 KIA OPTIMA
2.4L
4 CYL
FWD
AUTOMATIC
153,000 MILES

The car stopped running, I could here the fuel pump running on and off. I changed the fuel pump. Now it wont come on at all. I put a wire I ran from the battery terminal to the pump and it turned on. So I replaced the pump relay. It still doesn't work and I get a strange 9 volt reading at the pump when I turn the ignition.
Can't find any prints on this. Do you guys have any idea what the problem might be?

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Hi Guiton,

IT seems like you have a bad connection somewhere, have you checked the fuse or corrosion? and test the voltage there as well, also check the voltage at the ECU relay voltage feed terminal, that could be the trouble.

Here is some links to get started,

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here is the wiring diagram for you to further test the problem

Let me know what you find, Best, Ken

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Wednesday, August 5th, 2015 AT 11:38 AM

GUITON

MEMBER
3 POSTS

Thanks Ken, the diagram was very helpful. I have power after the ignition switch, but it doesn't make it to the fuel pump relay. So I put a jumper on it, and the fuel pump ran but the car wouldn't start. The old fuel pump relay clicks on and off like the new one and the old fuel pump works when I put it to the battery. I 'm thinking the ECM is problem the whole time. Is there any way to check it, before I replace it?

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Monday, August 10th, 2015 AT 6:20 AM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Hi Guiton,

By fuel pump relay you mean the ecm relay, the fuel pump doesn't have a relay? See if there is 12 volts at the pink wire heading into the relay, and then the gray wire heading to the fuel pump when the engine is being cranked over, please let me know.

Best, Ken

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Monday, August 10th, 2015 AT 4:10 PM

GUITON

MEMBER
3 POSTS

Yes ecm relay, I have power on the pink wire after the ignition, but don't
have it on the pink wire at the relay. I checked all the fuses and there good. On the pink wire I can't make out what is between the ignition and the ecm relay. I have power on the orange wire at the relay all the time.

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Tuesday, August 11th, 2015 AT 8:28 PM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Hi Guiton,

It looks like it is a junction block and a fuse, be sure you are checking the correct pink wire, there are two of them, the one you want to check is next to the orange wire. Please get back to me, we'll get this fixed! :-)

Best, Ken