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anyone ever have this problem?

  • Thread starter Thread starter 89blkgt
  • Start date Start date Jun 13, 2005
8

89blkgt

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Aug 1, 2004
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west springfield
Jun 13, 2005
#1
  • Jun 13, 2005
  • #1
hey guys,
Im on the fourm all the time but i never post, Cause i dont get good replies. Well heres the problem, I have a 1989 gt with mods in my sig, and i have gone threw 3 going on 4 190 fuel pumps. The first went out on me i replaced it with a mustangs unlimited 190. Then it craped out about a week later, let the car sit for a day or 2 and then it just started. I drove the dcar for about three more weeks with out any problems. Then it acted up again, so i pulled the tank and replaced it once again.(then took the car off the road days later) I just got the car back togeather about a month ago and i was at a buddys house and it **** the bed on me again, but it started up and i drove it home. then i go to restart it and it will not run the fuel pump. I have tryed to reset the trunk switch and still nothing. Has anyone ever had this problem with one of there stangs? Any help or sugestions to what might be causing my fuel problem would be awsome thank you
Tim
 

srothfuss

Last night I stabbed the same guy 7 times in a row
Oct 17, 2004
1,796
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0
Woodward Ave.
Jun 13, 2005
#2
  • Jun 13, 2005
  • #2
I haven't had a problem with my fuel pumps on any of my cars. When you cook your fuel pump is the gas tank empty? With your old pumps, have you tried to test them once you remove them from the tank?
 
H

hrspwrjunkie

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Dec 15, 2004
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Jun 13, 2005
#3
  • Jun 13, 2005
  • #3
The first thing I would check would be the fuel pump shut-off switch in the trunk to make sure it isn't what's giving you the problems.

I also prefer to use factory stuff in my car...if your engine isn't requiring the fuel of a 190, then go back to factory. Those pumps actually flow plenty well. If that isn't possible, then I'd go with the Ford Racing pump. I've never had a lick of trouble with them.
 

jrichker

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Jun 13, 2005
#4
  • Jun 13, 2005
  • #4
Fuel Pump Troubleshooting for 87-90 Mustangs

Clue – listen for the fuel pump to prime when you first turn the ignition switch on. It should run for 5-20 seconds and shut off. To trick the fuel pump into running, find the ECC test connector and jump the connector in the lower RH corner to ground. See http://www.mustangworks.com/article...c-iv_codes.html for a description of the test connector. If the relay & inertia switch are OK, you will have power to the pump. Check fuel pressure – remove the cap from the schrader valve behind the alternator and depress the core. Fuel should squirt out, catch it in a rag. A tire pressure gauge can also be used if you have one - look for 37-40 PSI. Beware of fire hazard when you do this.

No fuel pressure, possible failed items in order of their probability:
A.) Tripped inertia switch – press reset button on the inertia switch. The hatch cars hide it under the plastic trim covering the driver's side taillight. Use the voltmeter or test light to make sure you have power to both sides of the switch
B.) Fuel pump power relay – located under the driver’s seat in most stangs built before 92. On 92 and later model cars it is located below the Mass Air Flow meter.
C.) Clogged fuel filter
D.) Failed fuel pump
E.) Blown fuse link in wiring harness.
F.) Fuel pressure regulator failed. Remove vacuum line from regulator and inspect for fuel escaping while pump is running.

The electrical circuit for the fuel pump has two paths, a control path and a power path.

The control path consists of the inertia switch, the computer, and the fuel pump relay coil. It turns the fuel pump relay on or off under computer control. The switched power (red wire) from the ECC relay goes to the inertia switch (red/black wire) then from the inertia switch to the relay coil and then from the relay coil to the computer (tan/ Lt green wire). The computer provides the ground path to complete the circuit. This ground causes the relay coil to energize and close the contacts for the power path. Keep in mind that you can have voltage to all the right places, but the computer must provide a ground. If there is no ground, the relay will not close the power contacts.

The power path picks up from a fuse link near the starter relay. Fuse links are like fuses, except they are pieces of wire and are made right into the wiring harness. The feed wire from the fuse link (orange/ light blue wire) goes to the fuel pump relay contacts. When the contacts close because the relay energizes, the power flows through the contacts to the fuel pump (light pink/black wire). The fuel pump has a black wire that supplies the ground to complete the circuit.

Remember that the computer does not source any power to actuators, relays or injectors, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/t...witchWiring.gif

http://www.veryuseful.com/mustang/t...inks-ign-ac.gif

http://www.veryuseful.com/mustang/t...91eecPinout.gif

Now that you have the theory of how it works, it’s time to go digging.

Look for 12 volts at the Orange/Lt. Blue wire (power source for fuel pump relay). No voltage or low voltage, bad fuse link, bad wiring, bad ignition switch or ignition switch wiring or connections. There is a mystery connector somewhere under the driver’s side kick panel, between the fuel pump relay and the fuse link.

Turn on the key and jumper the fuel pump test connector to ground as previously described. Look for 12 volts at the Light Pink/Black wire (relay controlled power for the fuel pump). No voltage there means that the relay has failed, or there is a broken wire in the relay control circuit.

Check the Red/black wire, it should have 12 volts. No 12 volts there, either the inertia switch is open or has no power to it. Check both sides of the inertia switch: there should be power on the Red wire and Red/Black wire. Power on the Red wire and not on the Red/Black wire means the inertia switch is open.

The Tan/Lt Green wire provides a ground path for the relay power. With the test connector jumpered to ground, there should be less than .75 volts. Use a test lamp with one side connected to battery power and the other side to the Tan/Lt Green wire. The test light should glow brightly. No glow and you have a broken wire or bad connection between the test connector and the relay. To test the wiring from the computer, remove the passenger side kick panel and disconnect the computer connector. It has a 10 MM bolt that holds it in place. With the test lamp connected to power, jumper pin 22 to ground and the test lamp should glow. No glow and the wiring between the computer and the fuel pump relay is bad.

If all of the checks have worked OK to this point, then the computer is bad. The computers are very reliable and not prone to failure unless there has been significant electrical trauma to the car. Things like lightning strikes and putting the battery in backwards or connecting jumper cables backwards are about the only thing that kills the computer.

Look for bad grounds/bad connections for the fuel pump power while you are checking out the wiring.
 
8

89blkgt

New Member
Aug 1, 2004
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west springfield
Jun 13, 2005
#5
  • Jun 13, 2005
  • #5
hey guys,
yeah i just tryed starting my car for kicks and it started, so i ran it for a while with no problems.I tryed turining off the car and back on numerous times and it is working just fine nothing weird happening. yes my car needs a 190 pump prolly a 255 wouldnt even hurt for my application.So my pump relay is located under the passenger seat?(are these common to go?) Is there something only causing my pump to work when it wants to or if the relay was bad it would just not turn on? jrichker hey thats for the hure reply i like that no i have alot of troubleshooting to do thanks alot! Yes it is a fms pump all three times. And yes i have checked my pumps when they were out of the tank and they still work! But when i put a new one in it works for a little while. thanks alot guys
Tim
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
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129
Jun 14, 2005
#6
  • Jun 14, 2005
  • #6
Tim, you gotta' slow down buddy. Read and type slower, and it will help you to find a solution faster (as well as allow you to be better understood, which will help Stangers to help you).

As JR's post says, the fuel pump on your 89 is under the driver seat, not passenger seat.

It sounds like you have an electrical issue with the FP circuit. Go through JR's list carefully and it should yield results (obviously finding the issue is easier when the car wont run).

I like to test at the FP relay socket when problems arise. The relay is like an intersection. Testing there shows you which direction to pursue.

And I agree with your fuel pump selection, given your mods. HPJunkie probably missed your sig when he said what he did. Walbro is the OEM supplier of FP's. And many other pumps are repackaged Walbros. And they are good stuff, IMHO.

Good luck.
 

NosPony

New Member
Apr 2, 2004
278
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Canton, Il
Jun 14, 2005
#7
  • Jun 14, 2005
  • #7
Maybe a loose wire. Maybe a loose ground.
 
8

89blkgt

New Member
Aug 1, 2004
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west springfield
Jun 14, 2005
#8
  • Jun 14, 2005
  • #8
I see whats ur saying hissin50 but im all fired up. Not to mention it is so hot right now. Well i just got out of final exams i am going to check that stuff out, ill let you guys know what happends thanks
Tim
 
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