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Charter Member
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72 Posts
Discussion Starter · #1 ·
The hot weather has apparently fried my fuel pump. I checked with my Chilton manual and there are three types of fuel pumps for my donor, 1988 Mustang GT, gas tank. I am not sure which one I have - Low Pressure In-Tank Fuel Pump or High Pressure In-Tank Fuel Pump. I know I do not have the external high pressure fuel pump so which one do I buy?

Also, I assume I have to empty the gas tank, disconnect the straps and lower the tank in order to change out the fuel pump.

Any help would be appreciated and thanking you in advance.
 

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FFCobra Craftsman
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3,806 Posts
High Pressure In-Tank Fuel Pump. And, yes, you'll need to drop the tank and disconnect the lines and wiring.
 

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FFCobra Captain
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11,720 Posts
Low pressure would be for a carb. High-pressure for EFI.

If you have a bone stock motor, I think the stock pump was 110lph (liters per hour).

Don't forget to disconnect the filler tube. Sounds obvious...but I almost forget to do it.
 

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Premium Member
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6,413 Posts
Tell me about it!!!...I've replaced so many pumps, I could go into the used pump business!...One thing that I found out...it may be a loose connection in the pump harness at the top of the tank, or fuel pump relay....Best to check the relay first...It's cheap enough ($12), so go ahead and replace it first...The connector at the top of the pump is also prone to failure...It is made in such a way , that once the connections get a little loose, it should be replaced...If the car runs sometimes, try starting it , and wiggle the connector lightly, up and down...if it stalls, that may be your problem.
Another test , for the connector, is to turn the key on, and wiggle the connector...if the pump starts and stops, time to replace it.
If you pull the pump, examine the connections from the pump to the bottom of the two posts...They are just riveted, and can become loose...Any movement , will cause pump stoppage.
If this is the case, a new "cage" is also in order.
If you decide to test the pump wiring in place, remember that the pump cycles for only a few seconds, before shutting down, so you must test the voltage at the instant the key is turned on.
The voltage will drop very quickly, so this is a two man operation.
Another easy test , if the pump doesn't come on, is to listen for the fuel pump relay to click...It's pretty loud...If it doesn't , than it isn't getting enough voltage to engage or it is bad.
Good luck, and let us know what you find.
 
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