Fuel Pump problems

[SteveyJ]

Hi there all.
Having problems with my Mk1 Golf starting!
Think it's down to the Fuel pump, it primes up but won't switch off when pressure has built up, just permently on. However there is fuel at the injectors and fuel pressure regulator so it is making it's way round!
Appears to be no leaks on any of the fuel lines. It's an aftermarket bosch pump on a corrado 16v lump on throttle bodies. Car hasn't been running for atleast 3 months and was working perfectly before this.
Anyone got any ideas? All components are new too.
Thanks Steve

[stevieturbo]

If you say it has fuel, the pump is on, and its circulating round teh injectors, and back to the tank.....

Why would you think the fuel pump is the problem ?? Sounds like its working perfectly to me.

Have you checked for a spark ?

[GreenV8S]

How is this behaviour different to normal?

For example on mine, the fuel pump priming is simply timed by the ECU - normal behaviour is that the ECU runs the pump for asecond or so after the ignition is switched on, and the only way for it to keep running is a stuck relay or a failed ECU.

[SteveyJ]

Well it was a stuck relay, changed it and it now works fine. The relay cut out and the car fired up fine. Put the old one back in and the problem occured again. Don't know why this stopped the car from working, if anything thought it would of started up and possibly of flooded the car

[SteveyJ]

Ok now this isn't the problem? Relay appeared to be sticking open across terminals so I replaced it, the problem has occured again with replacement relay!!!

What I can't work out is why the car won't start when pump is whirring all the time is it just due to not enough pressure in fuel line?? Due to a leak(which I can't see)

But that won't make sense to me as if I let the pump prime jigle relay around it will switch across car will run fine until fuel gets low, then if I adjust the relay again to kick in pump car will work again.

Can anyone help? Am I missing something really stupidly obvious! If I don't reply to anything today I will next week as I'm off on hols tomorrow (in a very miffed and fustrated mood! lol)

[Mikey G]

Perhaps the car wont start due to the fuel pressure regulator going open circuit and just pumping fuel back to the tank?
Also i had a fuel pump fail due to water in the tank causing the one way valve in the pump to fail and not get enough pressure into the system, it would pump but not enough.

Not sure on the relay problem though..

[desmo]

Put some fuel in the tank!

[steve_D]

Perhaps the second set of contacts in the relay hold the ignition off until the fuel comes to pressure. When the pressure is up the relay trips over and makes contact for the ignition.

Steve

[SteveyJ]

Thanks Guys.
The tank does have fuel in, checked that.
Not sure about water in tank though?
Mikey I've emailed you a little question if you don't mind?

[morrisman]

SteveyJ said:

Thanks Guys. The tank does have fuel in, checked that. Not sure about water in tank though? Mikey I've emailed you a little question if you don't mind?

Is there a fuel pressure sensor that might be playing up, and not allowing ignition circuit unless fuel pressure is up to scratch?

Drain some fuel off from the pressure side into a jam jar. Water will show up as little jellyfish at the bottom.

[SteveyJ]

After everything it was down to a faulty loom broken wires in loom giving an intermitent problem so all went back to webcon and fixed! Thanks for all your advice people!