Resolved 2G No power to fuel pump.....

[222deuce222]

I've been reading for weeks on how to fix this problem and I still can't figure this out. My 98 gst just shut off on me one day while I was driving it and wouldn't start back up. There is no power going to my fuel pump and so far I have changed the "mfi/fuel pump" relays, I am getting power to both of the relays, change the "engine" fuse in the engine bay. I ran a 12v power supply to the fuel pump connector under the hood and I got power to the pump but I don't understand why I am not getting power the normal way. The pump is also rewired and I've changed the inline fuse and the relay on the pump. There is also power going to the relay on the rewire kit also but not going to the pump. I am also getting spark to the coils and kind of lost at what to do at this point.

 

[92AWDHX40]

Check connection at the pump, grounds too, bad pump Maybe.

 

[222deuce222]

The pump works because i ran a 12v to the pump and a ground and the pump cut on, there isn't power getting to the pump.

 

[jakk220]

Check connection at the pump, grounds too, bad pump Maybe.

I agree. Check the connector for the fuel pump. Might not be making good contact with the pins on the fuel pump.

 

[boostdawd]

He mentioned the pump does turn on when 12v is applied on the fp test connector under the hood. Fp checks out boys. I would recommend testing your MFI relay. The whole system works together to give u fuel. U may need help from a buddy but check to see if the values change when cranking the engine.

 

[222deuce222]

I Also installed a new mfi sensor

 

[92AWDHX40]

New,doesn't mean always working.

 

[pauleyman]

Doesn't the check connector just trip the relay?

I've been reading for weeks on how to fix this problem and I still can't figure this out. My 98 gst just shut off on me one day while I was driving it and wouldn't start back up. There is no power going to my fuel pump and so far I have changed the "mfi/fuel pump" relays, I am getting power to both of the relays, change the "engine" fuse in the engine bay. I ran a 12v power supply to the fuel pump connector under the hood and I got power to the pump but I don't understand why I am not getting power the normal way. The pump is also rewired and I've changed the inline fuse and the relay on the pump. There is also power going to the relay on the rewire kit also but not going to the pump. I am also getting spark to the coils and kind of lost at what to do at this point.

Youre getting power to the relay? You mean an aftermarket relay from a rewire? If that's the case you found your problem.

 

[shinzon]

When the ignition switch is on, the load side of the fuel pump relay is powered. The ECU is in control of the fuel pump relay by drawing the control side of the relay to ground on pin 8 when it determines the fuel pump should run, which completes the circuit on the load side of the relay, passing power to the pump.

Things that could cause no power to the pump:
Bad fuel pump relay
Bad connector at pump
Wiring between the fuel pump relay and the pump connector
Wiring between ignition switch and fuel pump relay
Wiring between fuel pump relay and ecu
Bad ECU

Doesn't the check connector just trip the relay?

Looking at the MFI wiring diagram in the '97 Talon manual, it looks like the test connector on the firewall applies power directly to the fuel pump, bypassing the fuel pump relay. This makes sense since you can use the test connector even with the key off, and the load side power on the fuel pump relay comes from the ignition switch.

 

[pauleyman]

When the ignition switch is on, the load side of the fuel pump relay is powered. The ECU is in control of the fuel pump relay by drawing the control side of the relay to ground on pin 8 when it determines the fuel pump should run.

Things that could cause no power to the pump:
Bad fuel pump relay
Bad connector at pump
Wiring between the fuel pump relay and the pump connector
Wiring between ignition switch and fuel pump relay
wiring between fuel pump relay and ecu


Looking at the MFI wiring diagram in the '97 Talon manual, it looks like the test connector on the firewall applies power directly to the fuel pump, bypassing the fuel pump relay. This makes sense since you can use the test connector even with the key off, and the load side power on the fuel pump relay comes from the ignition switch.

I didnt check the circuit diagram. Surprises me though.

 

[222deuce222]

Youre getting power to the relay? You mean an aftermarket relay from a rewire? If that's the case you found your problem.

No, I mean power to the Mfi/fuel pump relay.... the main power wire to the pump has no power, the original black and blue I believe wire

 

[Yellow Talon 2d]

Had the same issue- the relay right at the pump from the rewire was the issue on my 95. Pulled my hair out diagnosing all other relays in center of dash behind radio and fuse box under hood- then found that one hanging under the car! (no wonder it was shot) Changed it and vroom! Hope this info helps.

 

[pauleyman]

Have you ruled out the things that feed the signal to turn the pump on. Crank angle sensor, cam angle sensor, or even a broken timing belt so neither of these sensors would be working because of that.

 

[Yellow Talon 2d]

pauleyman has an excellent point with cas/crank possibility

 

[jakk220]

Have you ruled out the things that feed the signal to turn the pump on. Crank angle sensor, cam angle sensor, or even a broken timing belt so neither of these sensors would be working because of that.

I thought about that earlier but saw in the post that he said he is getting spark. I thought if the crank or cam sensor was bad, it would not get spark either.

 

[Yellow Talon 2d]

For sure no spark if crank signal gone, not sure about CAS tho...

 

[pauleyman]

I thought about that earlier but saw in the post that he said he is getting spark. I thought if the crank or cam sensor was bad, it would not get spark either.

I missed that but I'd still like to know how it was checked.

 

[jakk220]

I missed that but I'd still like to know how it was checked.

Yeah that would be nice to know. If it is actually getting spark, I would just put power to the pump and see if the car starts. If it does then you know it is isolated to the fuel pump wiring / relays.

 

[222deuce222]

Yeah that would be nice to know. If it is actually getting spark, I would just put power to the pump and see if the car starts. If it does then you know it is isolated to the fuel pump wiring / relays.

I've put power to the pump from the test connector and the car starts.... I also change the relay at the rewire kit

I've read that if the cas is bad I would not have spark or fuel but I have spark

 

[jakk220]

If the CAS was bad the car wouldn't start. You might have an ECU problem.

 

[222deuce222]

Thanks everyone but I’ve figured it out, there was a wiring issue and once I found and fixed it, the car fired right up.

 

[92AWDHX40]

Nice man .

 

[boostdawd]

Thanks everyone but I’ve figured it out, there was a wiring issue and once I found and fixed it, the car fired right up.

What exactly was the wiring issue?

 

[dsm nuff said]

Thanks everyone but I’ve figured it out, there was a wiring issue and once I found and fixed it, the car fired right up.

What was the wiring issue?