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

Discussion in 'The Garage' started by Twista, May 20, 2006.

  1. Twista

    Twista Legend

    Messages:
    6,042
    Likes Received:
    76
    Joined:
    Mar 7, 2006
    This is a PM i sent to someone so it may be formated strange.

    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.


    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.
     
  2. Matt94GT

    Matt94GT Legend SN95 Supporter Retired Staff

    Messages:
    11,861
    Likes Received:
    56
    Joined:
    Jan 10, 2006
    Location:
    Victoria, British Columbia, Canada
    Does your car run worse with a very low/almost empty tank? that is a sign of a weak pump as well.
     
  3. 94twinscrew

    94twinscrew Active Member

    Messages:
    465
    Likes Received:
    0
    Joined:
    Apr 5, 2006
    first off, your f/p is right on if it's a stock regulator,....with vac attached,you should be anywhere from 27-32. There are so many dirrerent variables to go into,but I'll try to give you a few quick ones.

    Pressure will eventually leave the rails after sitting for a while, that's normal. It's when you turn off the car,and watch the tester gauge move within 3-5 minute, that's when you have leaky injectors. The pressure falloff that you have, leads me to believe that the injectors have seen better days. One thing to try is when you go to start your car, key on the ignition so that power goes to the fuel pump,but does not turn over....do this twice before you actually go to start it......if that helps,then you found your problem.
     
  4. Twista

    Twista Legend

    Messages:
    6,042
    Likes Received:
    76
    Joined:
    Mar 7, 2006
    The on postion thing doesnt work @ all for my car. I tried it before and it still gives it a hard start. I was told my injectors was okay and they wasnt wet. With my car the pressue starts to drop to 0 soon as the car turns off which ins't normal i was told.

    So do you think the whole fuel pump is going?

    Btw, this started when it got hot outside. Not 2 my surpise since its cooler out today i tried to start up the car and it cranked with 1 try :-\ WTF! When its warmer its struggles to start. Im not sure if it was a conwidnece*sp* or thats another problem.
     
  5. 94twinscrew

    94twinscrew Active Member

    Messages:
    465
    Likes Received:
    0
    Joined:
    Apr 5, 2006
    Just because the injectors don't "appear" to be wet on the outside, doesn't mean that they are good. When non-discus injectors go bad, they tend to weap into the lower intake,past the pintle needle. This is where you see a pressure drop. This also contributes to hard start issues,and poor fuel economy.

    My suggestion for the hard start issue would be to first change out your fuel filter,if it doesn't improve anything....then attack your injectors,then pump. With the age of the car, it would be in your best interest to do all three anyway. IMO
     
  6. Tattoogod

    Tattoogod Active Member

    Messages:
    278
    Likes Received:
    0
    Joined:
    May 8, 2006
    what ive done in the past is slightly turn the injectors back and forth ..kinda reseats them,but if the internals are bad then thats another story.the fuel pressure reg could be faulty.you could take the injectors to have them pressure tested.keep us informed on the progress