no buzz from the fuel pump

[Moshiko Levi 10]

i always had the buzz sound from the pump fuel befor i start the eongie - but now its stop 2 weeks ago

the car still working well... but no buzz

why ?!?!?!?

thanks :)

[Sean_Jaymo 0]

If it's not broken, don't fix it.

[Moshiko Levi 10]

i have 3.4v in the Fuel Pumps Power harness - do you know why ?

[davidwort 0]

which engine?

[Sean_Jaymo 0]

If the voltage is that low, you likely have a corroded wire joint somewhere. Most likely at the pump end as that is more exposed. the other end of the power feed goes into the back of the fuesbox, Plug G1/8. Check for continuity and resistance.

 

I'm assuming that the relay is clicking over if you are getting a voltage at the pump plug. If you have access to VCDS, do you get any Lambda faults?

 

If you remove the relay (numbered 67 or 167) from position 12, do you get voltages from either pin 2 or 6 with the ignition in the run position?

 

If you short pin 6 to pin 4, do you get 12v at the pump plug?

 

Pin 3 when the Ignition is on should go to ground via the ecu.

Edited July 4, 2014 by Sean_Jaymo

[Moshiko Levi 10]

If you remove the relay 167 from position 12 , i get voltages from either pin 2 or 6 with the ignition in the run position of 12v !

but now somting change - i still dont hear the buzz from the pump when i do the ignition on but the car back to live - but after 20-30 sec the engine is on it make a sonude for 1 sec like it going to turn off and fix him self after 1 sec . it go the some evry 30 sec

1 - what it can be now ?

2 - if the engine is on how much fuel Pressure need to be ? its show 35psi

[Sean_Jaymo 0]

Depends on your engine. The fuel pump will only turn on if it senses a pressure drop. 35psi is only 2 and a bit bar. I believe the VR6 usually runs at 4 bar or around 60psi.

 

What voltage do you get at the fuel pump plug if you bridge pin 6 and 4? Should be 12v or so. If you are not getting 12v at the fuel pump plug, you will find the pump won't run at full power and not supply full pressure.

[Moshiko Levi 10]

now i do get 12v when i bridge 4 and 6 but it take me 7-10 sec to start the engine

i have 1990 corrado 16v swaped 10 years ago to 20vt AJQ

i alwayes heared the pump fuel when i turn the ignition key on - now it gone...

[Sean_Jaymo 0]

What condition is the fuel pump in then? Is it original? Is the relay latching securely?

 

It sounds like it could be a failing pump. If you are getting 12v at the fuel pump plug when the relay is fitted and the ignition switched on then all symptoms point to a bad pump.

[Moshiko Levi 10]

it past more then 1 houre befor i was in the car and now the gauge of the fuel pressure is 25 psi .

Is it proves something about the pump?

i have walbro 255 less then year and maybe 500 km :)

[Sean_Jaymo 0]

Do you get 12v at the pump now? You said you were getting 3v or so earlier?

[Moshiko Levi 10]

yesterday night and today morning i had 3.4 - but 3-4 houres ago its change to 12v . i dont know how

but i still i cant strart the car - its take me 7-10 sec until its start . after the engiמe is on for 20 seconds the engine almost shuts down for one second and then again works for 20 seconds and then again almost shut down for one second and so continues ...

[Sean_Jaymo 0]

Do you have a code scanner or VCDS? Have you taken the pump out of the tank to see if there is anything blocking the pickup?

 

I'm assuming you have plenty of fuel?

[Moshiko Levi 10]

yes i have VCDS .i didnt take the fuel pump out yet - i have full tanks of fuel - but now it stop worknig the the corrdo cluster - its show me thet its empty :(

i chek the wier from the fuel pump to the fuse box and its fine

what it can be ?

[Sean_Jaymo 0]

You have a loose plug somewhere in the fuel pump assembly potentially. Take it out and have a look.

 

Do you have any fault codes?

[Moshiko Levi 10]

i dont have any fault codes :(

i checked yesterday the wiers from the pump to the fuse box and it was fine.

i will open now the fule tank and will check the wallbro and te wiers over ther .

by the way - i remmeber when it all started .

I changed the Coolant Temperature Sensor - i open it when the car was hot :( and seens then i have this problem...

Do you think it is related?

[Moshiko Levi 10]

I opened the fuel pump tank and all seems right - all the wiers are conncted .

I have a question - when I turn the key on - i need to hear the pump start working and I did not hear it right now !

which of the connections gives this order to the pump to start working?

[davidwort 0]

1st step with fuel pump problems is to change the fuel pump relay on the fuse board/box, location 12, usually numbered 67 or 167 I think, can't miss it, it has two huge flat connector pins and is usually grey or blue.

[Moshiko Levi 10]

this was the first thing i did .

i bought the original from VW (42 GBP )

still the some

[Moshiko Levi 10]

Sean_Jaymo - Today I checked the connection of G1-3 and offline - that connects electronic throttle me in the car - when I give swatches is not receiving power

Could be that's why the fuel pump does not start to work?

Edited July 8, 2014 by Moshiko Levi