Jump to content
SAU Community

Fuel pump hissssssss

NCred02

By NCred02,
in General Maintenance

 Share

Recommended Posts

NCred02 Contributor

NCred02

Posted
Posted

Let me start by saying I do a search before heading here to absorb the massive knowledge here. And thank you for all the help!!!

When we turn the key to ignition on, but not start, the pump sounds like a tire thats letting air out. When I remove the gas cap there is a lot of pressure built up.

The car also takes three tries to crank it over and you have to have your foot on the gas pedal.

The three lines , two on the pump, and the other one that runs to? What is that?

Have a good weekend!!!

 

 

Link to comment
https://www.sau.com.au/forums/topic/482923-fuel-pump-hissssssss/
Share on other sites
GTSBoy Grand Master

GTSBoy

Posted
Posted

There is a breather system, via the charcoal canister in the engine bay, to a vacuum source on the inlet manifold. This is an emmission control to prevent fuel vapours escaping to atmosphere. They are caught in thee charcoal canister and burnt off when the engine is running. This system should be plumbed up properly and working because it doesn't hurt anything and is good for the environment.

If it is not plumbed up and working properly, then it could cause all sorts of odd behaviours. But I would be very surprised if it could interfere with starting. A pressurised tank would not make it hard to start. Should make it easier to prime the fuel rail, if anything.

If it is pressurised, then that could just be from warm fuel, but, if some numpty has plumbed it up wrong, it could be boost, which would be bad, and bad. You could pop the tank in the most extreme outcome imaginable.

  • Thanks 1
Duncan Grand Master

Duncan

Posted
Posted

do you have any way to get a fuel pressure gauge on the system? my guess is the pump is simply dying. if you don't have something any decent mechanic should be able to check static fuel pressure for you.

re releasing pressure when you open the cap, this is normal and fine. The cap should be vented to allow both air in as the tank empties and air out if the tank heats up and the fuel expands, which you might notice most during spring as the weather gets warmer (not that I know if it is spring where you are, there is no location on your profile :))

  • Thanks 1
NCred02 Contributor

NCred02

Posted
  • Author
Posted

@GTSBoy  @Duncan

 

Found the issue. The hose on the fuel pump was oversized and had a small split.

Still getting a lot of pressure when removing the cap and when fueling the pump shuts as full multiple times.

I'm thinking vent line on tank either blocked or pinched

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Duncan
      R32 Gtst - Track Car

      By Duncan · Posted

      Hope you aren't too sore after that one, might take a day or 2 to notice yet and I guess it is a loooooong drive home. On the bright side, tube frame front end is a thing at superlap, right?
    • Dose Pipe Sutututu
      R32 Gtst - Track Car

      By Dose Pipe Sutututu · Posted

      https://www.facebook.com/share/p/18rmVb1SKB/ 
    • GTSBoy
      Leak from Tokico BM50 Brake Master Cylinder

      By GTSBoy · Posted

      The chart of front pressure to rear pressure (with one being on the x axis and the other being on the y axis) is not a straight line on a typical proportioning valve. At lower pressures there is a straight line with one slope, and at higher pressures that changes to a lower slope. That creates a bend in the line at that pressure, called the knee point. If you do not change the proportionng as the pressure gets higher, you will suffer excessive pressure (at one end of the car or the other, depending on which way you look at the proportioning action) and then get lockups at that end. The HFM BM57, from my memory of previous discussions, is based on the BM57 from a different car (to a Skyline), with a different requirement for the location of the knee point and the distribution of pressure front to rear, and so is not a good choice for an upgrade on a Skyline. Here's a couple of links to some old posts, one from here, one from elsewhere. A lot of it pertains to adjustable prop valves, but the idea is the same. There are plenty of discussions on here about this issue from al the many years of people wanting a cheap/accessible option. https://grassrootsmotorsports.com/forum/grm/learn-me-brake-proportioning-valves/236880/page1/ https://grassrootsmotorsports.com/forum/grm/learn-me-brake-proportioning-valves/236880/page1/  
    • No Crust Racing
      R32 Gtst - Track Car

      By No Crust Racing · Posted

      Yeah dunno why johhny posted that here with no context, just post on FB/insta bro where he put it up?  Laine had an off at T4 during Thurs prac, he's ok, car is less than perfect, they are done for the weekend, he can fill in the rest. Bando also binned it like 100m up the road.   
    • MBS206
      R32 Gtst - Track Car

      By MBS206 · Posted

      I feel there must have been a FB/insta post and the weekend did not start well at all I hope everyone is all okay
×
×
  • Create New...