Is my fuel pump suppose to get power with key in the "on" position?

[RotaryRyan]

My fuel pump is only getting power when the key is turned all the way and trying to start the car. Is this normal?

95 GST

Thanks

 

[DSMeclipse4G63]

yes if it didnt get power your car wouldnt have fuel pressure to start.

 

[RotaryRyan]

my question was. is it suppose to get power when the key is in the on position or only when youre trying to start it?

 

[heavyD]

my question was. is it suppose to get power when the key is in the on position or only when youre trying to start it?

Fuel pump power is linked to ignition. No ignition, no fuel pump.

 

[RotaryRyan]

So the fuel pump shouldnt "prime" or whatever before the key is actually on "start"?

Im sorry for the stupid question. but i have been told by a lot of people that the fuel pump should come on even if you turn the key to the "accessory on positon" and dont turn on the starter to prime it.

 

[myvectorbroke]

I have a Haynes manual for my 90 TSi Awd that specifically states that the fuel pump should come on with the key in the "on" position, engine off, and that it will shut off after two seconds if no ignition signal is detected. Mine's even done that once or twice, too. So yes, technically, it should, though it may not be doing so. I'm trying to track down my fuel pump relay, but unfortunately, my manual doesn't mention where exactly it is. I've changed my EFI relay, and that didn't help. The pump is working, and the wires are intact all the way to the pump itself (I took it out and checked), but I can't figure out why the darn thing's not kicking on until I turn the engine over. Hopefully I can find an answer in the forums.

 

[steve]

On a 1G the fuel pump doesn't get power until the ignition switch is in the START position. The fuel pump part of MPI relay (inside the passenger side of the console below the radio) on a 1G has two inputs, one from the starter circuit and one from the ECU. If your Haynes manual says that the pump should run with the ignition in the RUN position rather than in the START position, it's wrong.

A 2G has a relay for the MPI and one for the fuel pump. The fuel pump relay only has a single input from the ECU and no connection to the starter circuit. I'll leave it up to the 2G guys to answer if the ECU powers the pump when the ignition is turned on or when the ECU sees the ignition switch in START.

Steve

 

[92redman]

^^You must burn up starters then, because you would have to hold your key in the "start" position to keep the fuel pump running. The only reason the the starter circuit has a coil going through that relay is to hold the switch closed while cranking since if the ecu doesn't see certain conditions(probably rpm) met after 2 sec, it will shut off the relay for saftey reasons. Notice how the ecu also has a coil for the fuel pump inside the mpi relay, that is so it can turn it on for the first 2 sec. and then keep it running once the engine is firing.

 

[steve]

I though we were discussing how the fuel system gets primed. As soon as the ECU sees the engine start (yes, it's RPM and pulses from the coil feedback) it activates it's input to the relay so that when you release the starter it keeps running. But the ECU doesn't activate the pump before it sees it start running on a 1G, it's the starter circuit that primes. On a 2G the ECU has to do it but the question is when.

Sorry I wasn't clear.

Steve

 

[DSMeclipse4G63]

my question was. is it suppose to get power when the key is in the on position or only when youre trying to start it?

yes if it didnt get power your car wouldnt have fuel pressure to start.

see I already answered your question...

 

[ZLODEY]

there are the following key positions = [OFF>ACC>IGN>START]
but for some reason on 2G cars fuel pump starts working only on START, while almost every other car gives +12V to the fuel pump on IGNITION position, so that you can fill the system and then start...
> anyone has an idea how to rewire fuel pump to start working on IGN position?

 

[brassc2007]

i have a 97 talon as soon as i turn the key to the on position the pump begins to prime, it is only on the 1g's that dont prime until your turn the motor over

 

[govproperty]

So, if I hook up a remote start switch to the start solenoid and the battery does that mean that the fuel pump will not turn on? I only ask because I am currently diagnosing a no start and I get no fuel pressure when doing this. Oh, it is a 1g.

 

[brassc2007]

why not just run a jumper wire from your battery to your pump with a inline fuse in it just as a test line or when someone is cranking the car over check to see if you even have power at the pump with a test light

 

[govproperty]

That's not a bad idea. I have my fuel pump rewired and if I pull the hot wire from the battery and touch it to the power input on the fuel pump. I have a 255 so I should be able to hear it turn on. Also, I should have time to make it to the fpr gauge to make sure it is pumping. Thanks.

 

[blackrosenova40]

Im pretty sure on 1g's, the cam ange sensor triggers the ecu, and then the ecu triggers the fuel pump relay.