the problem i am having is the fuel pump wont cycle on ive checked the pump the inertia switch the relay and nothing it just died while i was out one night i replaced the battery msd box the coil and nothing any help would be greatly appreciated because as of now my car sits broken. justthought id ad that the car also wont let me do a diagnostic on it the car obviusly wont start but i still should be able to do a koeo test?  

have you tried replacing the fule pump itself?  

Sounds like the pump has gone bad. I'd change it and see what happens.  

i hooked the pump up out of the tank and it still ran i do have another pump on order. wouldnt the pump not run at all if it where bad?  

You need to test for power with a test light to verify if the pump is getting power. The fuel pump relay is under the drivers seat. If no power check you fuses and the relay to see if you have power to and out when cycling the key.  

i have no power to the pink and black wire going to the fuel pump relay this is an 87 so i dont beleive that there are any fuses protecting it i replaced the relay will have new pump on tuesday. but with no power to that relay and i still think i will have a problem any ideas ?    

Hi, Just thought I'd let you know you're not alone. I'm working on an 87 GT, same problem, but I also lost the ground to my injectors. I was told if I find where I lost the ground, it should run again. If you want, when I make progress I'll post it for you, if you could do the same? Thanks.  

this wire that you are talking about goes straight into the battery side if the starter relay that when the key is turned on, the starter gets a charge. This wire stays hot at all times.  But the computer tells the relay to let the power thru to turn on the fuel pump. There is a fuseable link tag at the terminal where the battery is hooked up. Try bypassing it, or run a wire from the battery to the relay.  

Wow this must be a common headache with this year mustang gts. Im having the same problems with my fuel pump relays and eec relays not getting any power.  

i had same problem ,i pulled pump ran hose in jar of gas gave it power it ran but pumped no fuel , switched to a1000 aermotive pump been showin camaros the bumper ever since  

ok my car cycles and primes now when the key is  in the run position. but i still dont have any power at the pink and black wire at the fuel pump relay. I tested the tan and light green and it not grounding. when i jumper it to a ground the pump runs continoulsy. still my car just cranks.  

Try swapping the relay out under the seat. If this is disconnected or bad the fuel pump will not see power.  

I have A 1989 90 Mustang LX 5.0 I need to know where Is the fuel pump relay located on my car.  

is located under the driver's seat.  

Hi guys, I found the fuel problem on my 87 mustang gt to be a bad ignition switch on the column. My symptoms were the same as yours. Hope this help. Good luck guys.