fuel pump dying signs? sdpatt help!

Discussion in 'Gen 1 & 2 - Engine, Exhaust, Drive Line & AC syste' started by adidas_kn, Apr 24, 2002.

  1. adidas_kn

    adidas_kn LOWSHO

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    what are the signs of a dying fuel pump? i think my fuel pump might be going out on me but i cant tell cause it might also be a big vacuum leak. it idle irratically for like 5 minutes the when you try to drive it completely bogs down. but the car will still rev in neutral and with the clutch in. i read the codes 3 times and it always came up with lean codes. used to have a fuel pump code but did not the last time. need help i need my car back. also the car did this 2 days ago, but the next day it ran fine, well not perfect but idled and drove decent. if it is my fuel pump, can somebody please tell me where to get a 190lph or 255lph pump cheap?

    i just cant win with this car! :mad:
    constant problems shoot

    <small>[ April 24, 2002, 08:29 PM: Message edited by: adidas_kn ]</small>
     
  2. Bizzy

    Bizzy Administrator Staff Member

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    Well, I'm not Scott and I can't give you the technical stuff that he can, but I can tell you about my own experience.

    My fuel pump never completely died, I got to it before that happened. But I experienced erratic idle for approximately 30-45 seconds after start. It made a horrible grinding/groaning noise when just the key forward before starting and a kindof whistling/buzzing sound while running. Sometimes the car would start and then die when parked on a hill with the nose up.

    That's about all the info I can offer. Hope it helps out a little.

    Repairs on my car seem to come in waves...a series of problems all at the same time or one right after the other and then no repairs for 6 months or better. Don't lose heart....just remember how she felt when she was running better and know that more those days are ahead. :)
     
  3. sdpatt

    sdpatt Sr. SHO Engr.

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    Beth covered many of the symptoms to look for. Thanks Beth. One of the simple checks is just turning the ignition key to ON and listening to the pump. It should emit a steady, hihg pitched whine. If it gurgles, whistles, changes pitch or makes no noise at all then your pump is either on its way out or already gone. If you can measure the pressure at the fuel rail Schrader valve you should see about 40 psig.
     
  4. adidas_kn

    adidas_kn LOWSHO

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    how do you measure the fuel pressure? what tool? where can i get one? the car starts right up. could this be a clogged fuel filter?
     
  5. COliveira

    COliveira SHO Member

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    When my fuel pump went out in my 93, I had some of the same symptoms. I would give the car a blast down the freeway and then when the pump was overheated, it wouldn't give me the fuel I needed on the city streets and it bogged and accelorated like crap all the way home. When I got home and let it sit while I ran inside and got my fuel pressure gauge, it cooled off and worked fine! After I changed it, all worked fine! Now in my 95, I'm getting a gurgling pump as soon as I start it up, not sure if this one is on it's way out. Hope this helps!

    -Chris

    <small>[ April 25, 2002, 05:55 PM: Message edited by: COliveira ]</small>
     
  6. naval-avi8or

    naval-avi8or SHO Member

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    When you turn the key on pump whinning is noticable. Unexplainable engine stalls while driving down the road.
    I had the exact same thing with my car it was my fuel pump. i've chimmed in on several other post dealing with the same problem. I broke down in the middle of BFE Mississippi. If you think Ford will screw you wait till your in the same situation and you will learn what a good screw'n like. As far as the pump they start that SHO whine and they can do that for a while. Then they start stalling but the problem just happens once in a blue moon and you can't seem to duplicate it for any one so they can't/you can't fix it cause you can't quit scratchin your head. So the only way you will diagnos it its to take a fuel pressure reading the second it happens. When the pump its self cools down the armature frees up and your back in bussiness. hotter tmps low fuel and driving distance determine how long it takes for it to freeze up.
     
  7. silverknight

    silverknight i race taurus?

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    currently on my car there is a loud whine coming from the fuel pump area, but i havent noticed anything else except when idleing sometimes it goes a lil low. hard my key in the ignition and put it in prestart mode.. it went eeee- then off... i dunno what that means. its been makin the eeeeeee noise for a while, but nothing else, dunno weather to change out the pump or wait till it dies, im not worried about getting "stranded" cause my freinds have a towtruck company... and we have another car to drive when it dies... but i dunno, help me out. this is on an SLO 3.0vulcan... so i cant really tell if it gets slow-er.
     
  8. sdpatt

    sdpatt Sr. SHO Engr.

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    Wow, you brought this thread up from the grave! It might have been more proper to initiate a new topic.

    The fuel pump is an electrically driven, high rpm, positive displacement pump. It should emit a steady, high-pitched whine as it does its job. Its job is to provide a steady flow of fuel to the engine. It is the job of the fuel pressure regulator is to maintain the pressure of the fuel at the setpoint independent upon much fuel the engine consumes. You can verify the fuel pressure by having the pressure measured at the engine's pressure port that is made available for this purpose.

    With a modern, fuel injected car engine, turning the ignition key to ON (without starting) should cause the pump to run for approximately 1.5 seconds to prime the fuel system and provide the required pressure at the injectors. The injectors are not allowed to flow fuel into the intake until the crankshaft position sensor detects engine rotation and the cylinder identification sensor (on the SHO) detects the specific cylinder position (for sequential port fuel injected engines). To start the engine, the engine control computer must receive these inputs and will then will initiate fuel flow and spark to sustain combustion and allow the engine to run on its own power.

    If you said that your idle speed gets a "lil low" sometimes, I would not be concentrating on the fuel pump to resolve this condition. That would probably be something like a idle air control valve or even something as simple as resetting the idle speed programming. If the battery has been disconnected to start this behavior, that is probably all that is necesasary to correct it.
     
  9. Denny

    Denny Taurus Homeland

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    Can a fuel pump go bad from just sitting for a year or two? I had a Walbro unit put in, can't recall which LPH flow but it gurgles when I prime the system now that I recall
     
  10. N3FOL

    N3FOL SHO Member

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    Fuel Pump Gurgle

    I've had my 95 SHO since '95 and I had noticed gurgle noise on the fuel pump for about four years now. I am at 141K + miles and still on my original FP. I have a feeling that this may be a normal symptom of a good working 'older' fuel pump. However, I should be thinking of replacing my FP this coming summer. :wave:
     
  11. sdpatt

    sdpatt Sr. SHO Engr.

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    A fuel pump can go bad in a car that has been in storage for a long period if there was water in the fuel tank. That would cause oxidation (rust) to deteriorate the pump. That would be indicated by lower output flows (pressure) and ususally longer crank times as the discharge check valve in the pump body would no longer maintain the pressure in the fuel line to the engine.

    The gurgling sound you are hearing coming from the fuel tank is more likely to be fuel vapor venting from the fuel return line to the bottom of the tank. The fuel return line check valve, basically a rubber duck call on the tank end of this line, is intended to provide some resistance to this return flow to keep the return line under a small pressure that would prevent the fuel from turning to vapor.

    This is not a driveability issue and has no bearing on the health of the fuel pump. It is not worth dropping the tank to replace this valve until the fuel pump is in line for a replacement.

    With a normally aspirated SHO engine, you don't need more than the 155 lph (liters per hour) fuel pumps. There are many cases of the 190 lph being used successfully, but the 255 lph pumps will cause complications with too much flow for the fuel pressure regulator to properly handle. Mounting the longer bodied 155 lph (or higher) pumps in the SHO will require trimming the metal line where the pump attaches.

    I have had a 155 lph Walbro pump humming in my tank for almost 200,000 miles. The extra flow capacity over stock has allowed this pump to perform for a much longer period of time than expected. Using fuel treatments to keep any water out of the tank has likely helped too.

    Scott
     

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