Fuel pump stays on after engine is turned off The pump continues to run for several hours discharging the battery

fuel pump is bad, there is no switch. fuel pump overheated. The fuel pump uses fuel in tank to keep it cool.

: ECM determines the start signal status by the signals of engine speed and battery voltage. The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine start ability. If the ECM receives a engine speed signal from the crankshaft position sensor (POS) and camshaft position sensor (PHASE), it knows that the engine is rotating, and causes the pump to operate. If the engine speed signal is not received when the ignition switch is ON, the engine stalls. The ECM stops pump operation and prevents battery discharging, thereby improving safety. The ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump relay, which in turn controls the fuel pump.


Does the car have spark , crankshaft position sensor

Do you know ?
*: ECM determines the start signal status by the signals of engine speed and battery voltage. The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine start ability. If the ECM receives a engine speed signal from the crankshaft position sensor (POS) and camshaft position sensor (PHASE), it knows that the engine is rotating, and causes the pump to operate. If the engine speed signal is not received when the ignition switch is ON, the engine stalls. The ECM stops pump operation and prevents battery discharging, thereby improving safety. The ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump relay, which in turn controls the fuel pump.
The relay is located in the IPDE E/R under hood fuse / relay box . Should show location on inside of lid

Several possibilities. One is that you said you checked the relay, but clearly either the relay is not getting power or is not working. Another is that the fuel pump only goes on for a few seconds if the motor is not running, so if you have left the ignition switch on, do not expect the fuel pump to keep running. You have to keep turning the ignition on and off. The system that is used to detect the engine running and shut down the fuel pump when the engine is not running, varies. I am mostly familiar with imports, and they tend to use alternator output to detect engine running so pump should stay on. Some US cars us the oil pressure switch, and you can tell because then the oil pressure switch has more than 1 wire.

What is your year--make--model--engine size? On a cold engine, you can try cycling the key on and off several times before you crank it, see if it helps? By doing that, your priming the fuel system.

Usually electric fuel pumps are in the gas tank, but, without year--make--model, I can't look up any info.

I had the exact same problem last year with my 2001 Alero 3.4L V6. It turned out to be that most of the copper strands in the multi-strand ground wire were broken, in the wiring harness passing over the transmission on the way to the fuel pump behind the fuel tank. The same ground wire is shared with several of the warning gages on the dash, causing several to remain lighted all the time. Both of the check engine lights, the brake light, the low oil light, and ABS light would all remain on all the time. Once the frayed portion of the ground wire above the transmission was repaired, the lights stayed out and the car started running normal, with the fuel now actually pumping gas under continuous high pressure to the engine.

Fuel not reaching fuel rail, battery low or discharged, or defective spark plugs.

Check your main fuel relay.



Fuel Supply System


PGM-FI Main Relay


Description


This PGM-FI main relay is located behind the dashboard


lower cover. The PGM-FI main relay actually contains


two individual relays. One relay is energized whenever


the ignition is on. It supplies battery voltage to the PCM,


power to the fuel injectors, and power for the second


relay. The second relay is energized for 2 seconds when


the ignition is switched on, and when the engine is running.


It supplies power to the fuel pump.


PGM-FI


MAIN RELAY



FUEL


PUMP


RELAY


Relay Testing


NOTE: If the engine starts and continues to run, the PGMFI


main relay is OK.


1. Remove the PGM-FI main relay.


2. Attach the battery positive terminal to the No. 3*


terminal and the battery negative terminal to the


No. 2* terminal of the PGM-FI main relay. Then


check for continuity between the No. 5* terminal and


No. 2 terminal of the PGM-FI main relay.


• If there is continuity, go on to step 3.


• If there is no continuity, replace the relay and


retest.



*: 8P CONNECTOR


To FUEL PUMP


3. Attach the battery positive terminal to the No. 4 terminal


and the battery negative terminal to the No.


7* terminal of the PGM-FI main relay. Then check


that there is continuity between the No. 3 terminal


and No. 1 terminal of the PGM-FI main relay.


• If there is continuity, go on to step 4.


• If there is no continuity, replace the relay and


retest.


4. Attach the battery positive terminal to the No. 1 terminal


and battery negative terminal to the No. 2*


terminal of the PGM-FI main relay. Then check that


there is continuity between the No. 5* terminal and


No. 2 terminal of the PGM-FI main relay.


• If there is continuity, the relay is OK;


If the fuel pump still does not work, go to Harness


Testing on the next page.


• If there is no continuity, replace the relay and


retest.



To PCM CONNECTOR


TERMINAL A4


To ST. SWITCH


To GROUND


To IGN. 1 To BAT


To PCM


CONNECTOR TERMINALS


A13 and B1


FUEL PUMP


RESISTOR


FUEL PUMP

If it only gives trouble after standing unused for several hours, I would suspect the gas lines, possibly. After sitting for several hours, if your gas lines are already gunked up, then it's difficult to get the fuel to the engine after sitting for several hours. Once you use it, and warm it up, then it's not as difficult getting fuel through gunked up lines. Just a possibility.

may need a new glowplug timer trie leaving the ingnition in on position a few seconds b4 cranking also u need 2 check ur not getting fuel flow back and loseing pressure at pump