Fuel Pump Problems 2004

[JJFarmer]

Just replaced the fuel pump on my sons 24' Supra. It quit on him again. I have no voltage at the pump and I don't think the relay is picking up either. I found 3 fuses at the motor and all are ok and have voltage. Does the engine module run the pump? Anybody have a wiring diagram?

[lively]

year make and model ? , electronic fuel pump follows :

Ignition switch, relay , ECU , Pump ..

relay should be a 4 pin . look on bottom to find what contact is not making , or if your even getting voltage at the relay block .... let me know

[JJFarmer]

Well, it's a 2004 Supra 24' with the 350. I found 3 relays under the cover plate over the engine control module. No idea which relay does what. Just know that one is not doing anything. Like I said, the 3 fuses are hot at the engine but no volatge at the pump. I wonder if the ecm is bad now. The thing ran fine until they stopped to pickup a rider. Then it would not start back up, just turned over.

[lively]

ok well to find out where the voltage is you need to determine the wires on the ignition switch ( like how many it has ) and look to see if the wires on the pump match any on the key switch , one of those wires are directing power to the relay for the pump , and another short way to help diag is run a jumper wire to the pump , or if you have a power probe you can apply power see if there is a ground issue or something simple ...

it sounds like a bad relay to me if you have a volt meter check continuity or ohms from your power wire to the battery ( or key switch ) you will prob need a long jumper to make it easier ...

The likeliness of a the module being bad is not likely in this case .. just a bad connection or loose ground

hope this helps and good luck to your fixing

[JJFarmer]

I swapped the relays around and the one plug never worked so I think all the relays are good. Guess I will try a jumper straight to the pump to check it.

[JJFarmer]

Finally worked on this today. Pump does work, jumped it out but motor won't start. I'm not getting a ground from the ecm. Not sure if I can read the ecm. I don't know if I have a bad ecm or something has the ecm locked out like another switch. I did get a Supra wiring diagram.

I did take the cables loose to clean them, then hooked back up. Tried the key and the pump ran when I turned the ignition on a couple of times, then that quit happening. That's why I'm leaning toward the ecm.

Opinions or next steps? This is a 2005, not an 04 by then way

[lowdrag]

I think there's also a safety that's somehow tied in to the oil pressure. Might be a stretch but maybe there's a fault with the oil pressure sending unit that is causing it to cut power to the fuel pump.

[JJFarmer]

I've tried to check the different switches to see if they have it locked out but no luck. I really need to get an tester to read any codes that might be set.

[Engine Nut]

I've tried to check the different switches to see if they have it locked out but no luck. I really need to get an tester to read any codes that might be set.

It is doubtful that any codes would be set. There are no codes associated with the fuel pump or ful pump relay. The following link will take you to an engine diagram. The ECM takes the green/white wire from the fuel pump relay to ground to activate the relay and turn the fuel pump on.

ftp://ftp2.indmar.us/Service%20Infor...%20-%205.7.pdf

[JJFarmer]

Still no luck. Jumped 12v+ to the pump to get it running and it does, but motor still won't start. I don't understand the crane sensor, I found a sensor around the harmonic balancer (about 7 oclock) but no wires ran to it. Looks like has never had any run to it either. I'm wondering if the crank sensor is somewhere else towards the back of the motor. Just got dark on me before I could trace out the 3 wires.