Fuel Pump??? Need Other Car Smart PPL in here...

97GTVerT · May 20, 2006

I have a 97 GT Mustang with pretty much stock everything. It seems after the car sits for along time it has a HARD time cranking back up. The 1st crank never fires up and the 2nd crank the stang fires up. I had a buddy look @ my car and he hooked up some guage thing to this fuel thing ontop of the injector rail. He told me to fire up the car to see what my fuel pressue was. On start up it @ 28 PSI which he said is low. He said my car should atleast be @ 34ish on start up. (or he might said 40ish.. i cant remember)

Now heres another problem. He said when the car is turned off the pressue is suppose to be stable and steady. However, on my car my fuel pressuse droped down from 28 to 15 within 10min. Now we believe when its having a hard time cranking in the morning because by than my fuel pressue has dropped down to 0.

What do you think it is? Fuel pump? We just changed the fuel filter and that didnt fix the problem.

My buddy is a mehanic so i trust his opinion , but im just wondering what some of you guys think?

01Steeda · May 20, 2006

I think he is correct

thomas91169 · May 20, 2006

hes probably right. the pump could be on its way out, and overnight when it sits, it leaks the fuel back into the tank. upon startup, it must re-pressurize the system, which takes a few cranks.

Dragstr05 · May 20, 2006

Sounds to me like the pump is just having a hard time building up pressure. In the morning, put the key in the "ON" position for a short while before you start the car, which will energize the pump and should start building pressure. If it cranks right up after you let it energize and build up pressure, then you know what your problem is.

97GTVerT · May 20, 2006

Dragstr05 said:
Sounds to me like the pump is just having a hard time building up pressure. In the morning, put the key in the "ON" position for a short while before you start the car, which will energize the pump and should start building pressure. If it cranks right up after you let it energize and build up pressure, then you know what your problem is.

i tried it numerious times and it still doesnt crank. You mean just turning the key to the on postion than off again than on again than off. Yep, it doesnt work still a hard 1st crank.

;] thanks for the replies guys

Yellow2002GT · May 20, 2006

I just replaced my pump tonight with a bosch 190lph pump and wow....what a difference! Car started right up and got rid of the low end shutters......If you got full exhaust and full intake work done you might want to upgrade your weak stock 110lph fuel pump.....mine was on the way out the door anyways!

"ED"

Dan_Soprano · May 21, 2006

did you change the fuel filter also? Preventative maint. is a life saver in the long run!

DropTopPony · May 21, 2006

Dan_Soprano said:
did you change the fuel filter also? Preventative maint. is a life saver in the long run!

OMG did Kilgore hack into Dan's username?

97GTVerT · May 21, 2006

Dan_Soprano said:
did you change the fuel filter also? Preventative maint. is a life saver in the long run!

Yep, he changed that out the day he looked over it.

Mike97gt · May 21, 2006

it's the fuel pump, very common problem the drain back valve fails on the pump.

Dragstr05 · May 21, 2006

97GTVerT said:
i tried it numerious times and it still doesnt crank. You mean just turning the key to the on postion than off again than on again than off. Yep, it doesnt work still a hard 1st crank.

;] thanks for the replies guys

No, what I mean is put the key in the "ON" position like your just going to sit in the car and listen to the radio or something. Once you put it in the on position, the fuel pump powers up. From what you were saying, if you let it build up pressure *before* you attempt to start the car, you will probably be able to get it to fire right up on first crank.

Twisted · May 21, 2006

It is not the fuel pump you retards!!! The pump cannot create pressure when it if OFF. He either has leaking injectors or a leaking fuel pressure regulator.

97GTVerT · May 21, 2006

Dragstr05 said:
No, what I mean is put the key in the "ON" position like your just going to sit in the car and listen to the radio or something. Once you put it in the on position, the fuel pump powers up. From what you were saying, if you let it build up pressure *before* you attempt to start the car, you will probably be able to get it to fire right up on first crank.

Ya, that way doesnt work also. I was told to try the on and off thing acouple times to charge it up also, but it still didnt crank. The way your saying is bascially, turn the key to the on postion and wait till all the lights on dash go off (air bag, low coolant, etc) than crank, but that doesnt work also.

Twisted said:
It is not the fuel pump you retards!!! The pump cannot create pressure when it if OFF. He either has leaking injectors or a leaking fuel pressure regulator.

Anyone else think its leakign injectors or leaking fuel pressue regulator? What do you mean create pressue? It looses pressue when the car is off, unless thats creating also?

Twisted · May 23, 2006

If the pump is not spinning it cannot create flow/pressure. When it is off the only pressure in the system is the pressure when it was turned off. If you have a leaking injector, the pressure can leak out there. If you have a bad regulator the pressure can leak out there.

Are 97's return or speed controlled fuel systems?

There probably is an overpressure relief valve somewhere in the system too.

Shiroelex · May 23, 2006

I think you misunderstand, Twisted. The same theory here applys to car tires. Once the air is in there, it should stay in there, unless there's a hole, or the valve stem is leaking. That's why they say to depressurise the fuel system when changing the fuel filter. Also, it's not a good idea to call everyone retards.

Like SVTTECH said, the drainback valves have been a problem before, and with the car being a 97, I'd say it's probably about time to look at that plug. If you don't want to drop the tank first, you could pull all your spark plugs, after the car has been sitting for a while and has lost pressure. If an injector has been leaking, that plug would be wet. Good luck, and keep us posted.

97GTVerT · May 23, 2006

Well im on the look for a cheap fuel pump right now.

BTW, this morning i let my car sit on the on postion for like 5min and this time it took 3 cranks to get it running ;[ *cries* I guess my pump is dying.

GoBabyVroommm · May 24, 2006

Get a fuel pump over nighted from Japan. WHATEVER IT TAKES! At least a Walbro 255. Its $105.00 shipped on ebay from most of the speed shops on there.

97GTVerT · May 24, 2006

Heres a WTF! I forgot to mention this started when it got warmer outside. Im not evne surpised since today its way cooler and guess what? The car started up fine on the 1st crank ;[

Twisted · May 27, 2006

Shiroelex said:
I think you misunderstand, Twisted. The same theory here applys to car tires. Once the air is in there, it should stay in there, unless there's a hole, or the valve stem is leaking. That's why they say to depressurise the fuel system when changing the fuel filter. Also, it's not a good idea to call everyone retards.

Like SVTTECH said, the drainback valves have been a problem before, and with the car being a 97, I'd say it's probably about time to look at that plug. If you don't want to drop the tank first, you could pull all your spark plugs, after the car has been sitting for a while and has lost pressure. If an injector has been leaking, that plug would be wet. Good luck, and keep us posted.

A pump is a little different than a tire. There are small gaps in the pumps internals that pressure can leak by. That is why they usually place a check valve after the pumping elements. (Technically a tire will lose pressure too, just over a much longer period of time.)

mineralgraygt · May 27, 2006

its a leaky injector or a bad regulator

Fuel Pump??? Need Other Car Smart PPL in here...

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