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Discussion Starter · #1 ·
Ok I have an 89 MX6 GT Turbo 4WS it has an issue where when it gets down to 3/4 of a tank of fuel it will act like it is loosing fuel going around right hand turns only but be just fine once straightend back out. Now it doesn't do this when the tank is full it runs perfectly fine any Ideas would be appreciated. I have searched the forms but not seeing my specific issue.
 

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Could be the circuit opening relay failing/failed or a short or bad connection in a wire somewhere that's cutting power for the pump.

I would just add a second ground wire at the pump and
Use an inline 15amp fuse and 40 amp Normally Opened automotive relay.
Run wire from the Battery to the fuse, from the fuse to pin 30 on the relay and from relay pin 87 to the fuel pump.
Connect relay pin 85 or 86 to chassis ground and the remaining pin (85 or 86) to ignition switched 12V +.

When the key is on in the ignition the fuel pump will run and when the ignition is turned off the fuel pump turns off.
 

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Discussion Starter · #10 ·
I am getting power to pump when I jump the test connection under the hood and probe the fuel pump hot line its reading battery voltage with the key on so relay and fuse are good as per Fords service manual that I have for this car
 

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Do you have ground at the pump connector?
If you do, than pull the pump and connect it directly to the battery and see if it still works.
If the pumps motor is toast, there could be a short in the wires to the pump.
There could also be a short in the ground going to the pump.

The reason I posted what "I would do" is because I would skip trouble shooting the factory 12v and ground supply going to the pump and rewire the them independently.

My ex shop partners 91 mx6 GT used to reset the radio and loose power to a bunch of other things would loose power on hard turns, everything grounded to the passenger side floor well, the car was rusted but not enough to brake ground continuity on the passenger side, checked everything and finally just removed the tape from the harness a few feet back, cut all the ground, soldered them together and grounded them to the dash, never happened again.

I wonder if the 4ws mx6 has a roll over sensor, I am pretty sure the probe did. It's like an air float sensor that's triggered if the car goes upside down and cuts power to the pump, if they fail and stop making continuity the pump wont run.
You can also take speaker wire and ring it directly from the battery + - and see if it builds pressure in the fuel lines.

Somewhere in here there in the complete 1988 work shop manual:
Index of /mazda

You are following all the steps correctly, but the wsm states after checking the wires for continuity if any connections/wires aren't working replace the harness, mechanics guides and common sense dictate replacing the wire.
But if you have a working pump all you need is a fused 12v+ source, an ignition activated relay or manual toggle switch and a good ground for the pump to function properly,
Why chase ghost on a 33 year old wire harness and systems when it's less effort to wire the pump to work properly and remove all doubt.
 

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Discussion Starter · #12 ·
It was the fuel pump that went bad I pulled it and tested it and all it would do is click. Put the new replacement pump in car fired right up so took it for a short drive and blew a fuel line under the hood, so yeah tracking gremlins of all sorts at the moment, and as far as replacing grounds I did do that also and it didn't help, and I have the Hard copy of the Ford Service manual for this car its like 4 inches thick. Thanks for replying all .
 
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