[riannone]

Hey Everybody,

Got the timing belt and the new crank angle sensor in the car. I now have spark, the tach now registers and the car tries to fire as opposed to just cranking. So now I am troubleshooting fuel as the problem. Gauge says 1/2 tank so that should be good. I do not hear the pump turn on when the key is turned to the on position.

I have the Kia wiring diagram but I am a little unclear. when I use the power probe I get no voltage on the Grey wire I get a good ground on both blacks. The blue wire gives me 11.5 and the pink is 4.5.

Question is can I apply 12 volts with the power probe 3 to all the pins on the white connector on the tank as a test and see of the pump turns on??

Or does someone have a pin schematic for the pump. or is the pump just bad. It is a rather pricey part and I don't want to just replace it as a test I would like to be sure it is no good first.

thanks so much

 

[DavesSpectra]

I just checked for a 2005 Optima 2.4L and there are two different nodel years...
up to 08/30/2004
and after 08/30/2004
The schematic diagrams are different for both.
I'm looking in the 2005 Optima ETM section of kiatechinfo.com for wiring around the gas tank.

The Blue/orange wire is a temperature sensor feed to the BCM so 11.5 is just relative to temperature.

The Blacks are ground (returns) and should be 0v.

The Pink is the fuel level sensor (full to empty) and will vary with how much gas is in the tank.

The gray wire is the power to the fuel pump and will have 12v on it when the fuel pump is turned on. It is powered by the "ECM control relay" which recieves it's turn on power from the ignition switch and is grounded through the green/orange wire connected to the ECM control line. This information is located in the "engine control system" area of kiatechinfo.com. Check to see if the ECM Control relay is being energized when the ignition switch is turned on. You should have voltage on pin 6 (B+) and pin 4 switch out to gas pump motor.

As for the gray wire going to the gas tank you can put +12v on this line and the pump should start. The pump will not run unless there are signals from the crank AND cam sensors...The ECM will NOT turn the pump on if either signal is missing so even "if" you manually power up the pump the car will NOT start if either the crank or cam signals are missing. Spark is also controlled by these signals via the ECM.
DO NOT PUT 12v ON the other lines as you WILL damage the sending unitis in the gas tank.

 

[riannone]

Dave thanks so much for getting back to me.

I am not getting 12v on the grey wire so I assume that the ECM relay under the dash may be at fault, as I believe there is no stand alone fuel pump relay it is tied in with the ECM relay. I also believe this is located in the center console near the radio.

Reading these wiring diagrams is new to me, so I am learning what it all means. Your explanation of all the wires involved was very helpful.

The car as far as I know is in perfect time, as I hear no interference when it is cranking. . The cam sprockets were perfectly aligned when I replaced the timing belt. I also replaced the crank sensor and the tach is registering a reading now when it cranks and it was not at all before.

Today I had my wife crank the car and I shot fuel into the intake and she backfired a flame out of the intake. In the old days this usually pointed to a car out of time. But with these newer cars I am not sure but I would assume that is the case.

Do you have any other ideas on what might be going on?? I am concerned now hat even if I get the fuel pump to work I may have a backfire problem.

ANY!! help you can offer me would be greatly appreciated.

thanks again.