Bad Fuel pump??? Help me out guys....

mystang94gt

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Jun 14, 2004

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Nov 30, 2004

#1

• Nov 30, 2004

• #1

Ok well I replaced the Harmonic balancer on my car two weeks ago and everything was great.....for one freakin day. I fixed the car weds night and by friday morning something was wrong. Went to start the car and it took about 5 seconds of cranking before it fired. Once it started it ran like sh**. Was idling very low and everytime I went to give it gas it would stumble all over the place. hard to even get it to rev over 2000 rpms. Then yesterday i went to try and start her again. she just kept on cranking and never even fired. You could hear the starter cranking and my voltage was fine. It just seems like it's not getting fuel.

What's the easiest way to check if she's getting fuel or not??

TIA

 

RIO5.0

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#2

• Nov 30, 2004

• #2

Easiest method is to crank it then hit the schrader valve on the fuel rail....put a rag on it first, in case it pisses out...

Can you hear the pump priming???

 

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wytstang

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Nov 30, 2004

#3

• Nov 30, 2004

• #3

Turn the key to the "on" postion that will turn the fuel pump on and you should here it buzz on. If you can have some one stang behind the car to see if they can hear it.

 

mystang94gt

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#4

• Nov 30, 2004

• #4

Well that was my first thinking that if it buzzed then it must be working. And it is buzzing when I put the key in the on position. So if I hear that its safe to assume the pump itself is ok? Or could it be barely working just not enough to run properly?

I'm kinda at a loss because it was running so good.

 

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wytstang

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#5

• Nov 30, 2004

• #5

Invest in a fuel pressure gauge that will tell you if the pump is weak or not.

 

mystang94gt

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#6

• Nov 30, 2004

• #6

I have one but its the one mounted on the fuel rail so I wasnt able to see what it was reading from inside the car. but my brother was watching it and he said it looked like f/p was dropping as I gave it more gas.

 

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wytstang

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#7

• Nov 30, 2004

• #7

It sound like the FP is losing pressure that's the exact same think my stock one did when I first bought the car. As soon as I would turn the car off the pressure would drop right away. It would take a few cranks or a couple of key cycles so it could prime it self to restart.

 

RIO5.0

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#8

• Nov 30, 2004

• #8

Didn't see you had the gage...after cranking will the gage hold any reading??

 

mystang94gt

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#9

• Nov 30, 2004

• #9

RIO5.0 said:

Didn't see you had the gage...after cranking will the gage hold any reading??

Click to expand...

Stupid question but by cranking you mean trying to start it right? cause it wont start at all right now. I can check that out tonight and see if it shows any fuel pressure. Will it show fp if the car isnt running?

 

RIO5.0

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#10

• Nov 30, 2004

• #10

mystang94gt said:

Stupid question but by cranking you mean trying to start it right? cause it wont start at all right now. I can check that out tonight and see if it shows any fuel pressure. Will it show fp if the car isnt running?

Click to expand...

Correct...its not starting tho...you just wanna see if its building pressure....that would tell me the pumps good....it may not hold pressure as sometimes the regulator is weak....hence the 3 crank to start as mentioned, but it will start when they do this...yours isn't starting at all...correct??
i would at least wanna see if the pump builds pressure....hardly any pressure being built while cranking would indicate its bad to me....not holding pressure, just building it...

how olds the filter???

 

mystang94gt

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#11

• Nov 30, 2004

• #11

Yeah its not starting at all right now. And My Fuel filter cant be more than 1 yr old.

So if I try and crank it over, should the fuel pressure be close to where I had it set? I had it set at 43 vacum off and like 38psi (i think) with the vacum plugged in. Should the gauge be showing similar readings just by priming the fuel pump?

 

RIO5.0

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#12

• Nov 30, 2004

• #12

Yes...just turning the key on the pump should build pressure...makes no dif vac on or off....you just wanna verify it builds.
actullt I set my F/P by just turning the key on...the moment youhit that key...blam..the gage should read what your setting is...you dont really need to crank the motor to verify pressure...the pump runs by electricity...

Dont rule out a bad TFI module either...a run to the parts store and they can test that...

I had a bad injector run me around for a week til i found it was the problem...ran like ass a couple times them flat out died and would do nothing but crank...was an Escort GT winter bomb...

have or can you pull the codes???

 

mystang94gt

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#13

• Nov 30, 2004

• #13

Right on thanks Rio. I am going to check that tonight and see what happens. BTW you just got my vote for stangnet member of the year. No one else I've seen has the knowledge AND the patience.

 

mystang94gt

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Dec 2, 2004

#14

• Dec 2, 2004

• #14

Alright Fellas looks like the FP must be the prob. Went to check on it last night put the key in the on position and the FP didnt make the slightest bit of noise. Tried it about 6 more times and finally by the 4 or 5th time it actually made a little noise. But the fuel pressure is no where near where it should be. And the car still wouldnt start. So I'm dropping the gas tank tom before I go outta town. Good thing I got a 190lph already. I'll let you know how it goes. Later.