Fuel not reaching fuel filter

Hi guys,

tried to start my 1986 cabby this afternoon for the first time in 6 months. There is a spark - managed to work out there is no fuel getting to the fuel filter. The lifter  pump was replaced about 3 years ago. I don't think the main pump has ever been replaced. Certainly not in the last 6 years. I can feel the main pump doing its thing when trying to start the car. Could it be one of the pumps?
I did notice the main pump buzzing a bit last year but to be honest that pump has always buzzed and speaking to a few folk on here that is fairly normal.
What should I be checking next?
regards
KP

 

Fuel pumps shouldn't buzzzzzzzzz.
Buzzing or whining is a sign that the motor is over working and trying to play the game, but can cause the FP relay to go out… or the pump burn out..

The Fuel pump is triggerd by the coil, which turns the fuel pump relay on.

That fuel pump is 75psi.  

I would find out by taking the Fuel line off the input side to see if it is getting fuel.

If it is, then crack loos the out put and direct it in to a bucket to see if it is getting fluid out.

Briano1234 said

Fuel pumps shouldn't buzzzzzzzzz.
Buzzing or whining is a sign that the motor is over working and trying to play the game, but can cause the FP relay to go out… or the pump burn out..

The Fuel pump is triggerd by the coil, which turns the fuel pump relay on.

That fuel pump is 75psi.  

I would find out by taking the Fuel line off the input side to see if it is getting fuel.

If it is, then crack loos the out put and direct it in to a bucket to see if it is getting fluid out.

I'll try that tomorrow. Do you know, which relay is the FP relay?
Thanks

www.cabby-info.com

To eliminate the FP relay, and aslo to make other tests easier, try this:

As you look at the relay plate/fuse box, the top left relay position is no1 across to no6, and the bottom row is 7-12. There may be some other relays clipped to the top - ignore those. The FPR is in position 2 - it is a very tall relay. Pull it and swap it with the relay directly beneath it in position 7, you have to rotate it by 180degrees so the big contacts line up. Now the FP will run as soon as you turn the ignition on, without having to crank the engine. Don't drive the car lie this as the FP won't cut out in the vent of a crash. As you have established no fuel at the filter (is that inlet or outlet?) turn on the pump and work your way back towards the tank cracking each joint until you get fuel. That should establish whether you have a blocked pipe or not. If the main pump is delivering fuel, you should measure the output over 30 seconds - if you have  pump with screw on electric connections it should be 900cc, if you have push on electrics it should be 750cc. If you are not getting this quantity either the pump is on the way out, or you have a restriction.

Have you physically checked the lift pump - modern fuels have more ethanol which attacks the rubber hoses inside the tank, the one that connects the lift pump to the sender - look for black gunge! Also check that the lift pump filter is in place and intact - I have found that sometimes they come adrift.

good luck
Lee

LeeO said

To eliminate the FP relay, and aslo to make other tests easier, try this:

As you look at the relay plate/fuse box, the top left relay position is no1 across to no6, and the bottom row is 7-12. There may be some other relays clipped to the top - ignore those. The FPR is in position 2 - it is a very tall relay. Pull it and swap it with the relay directly beneath it in position 7, you have to rotate it by 180degrees so the big contacts line up. Now the FP will run as soon as you turn the ignition on, without having to crank the engine. Don't drive the car lie this as the FP won't cut out in the vent of a crash. As you have established no fuel at the filter (is that inlet or outlet?) turn on the pump and work your way back towards the tank cracking each joint until you get fuel. That should establish whether you have a blocked pipe or not. If the main pump is delivering fuel, you should measure the output over 30 seconds - if you have  pump with screw on electric connections it should be 900cc, if you have push on electrics it should be 750cc. If you are not getting this quantity either the pump is on the way out, or you have a restriction.

Have you physically checked the lift pump - modern fuels have more ethanol which attacks the rubber hoses inside the tank, the one that connects the lift pump to the sender - look for black gunge! Also check that the lift pump filter is in place and intact - I have found that sometimes they come adrift.

good luck
Lee

Thanks.

I checked all connections back from the warm up regulator and no fuel at all. Checked all the way back to the inlet to the fuel filter.

Is there anything else between the filter and the pump? where does the accumulator feature in the fuel flow process ?

So if I swap the relays over and I get fuel at the inlet to the filter does that tell us the relay needs replaced?

I'd need to jack it up to see what connections are on pump. Might be an idea to change the pump anyway if its been buzzing away when it shouldn't be. - are the pattern pumps any good? Are genuine still available?

I was told by previous owner that the lifter pump, the fuel tank and filler neck were all replaced about 5 years ago. Is there a guide on here on how to check the lifter pump? my seats and carpet are currently out so I have full access no problem

regards

If swapping the relay fixes everything, then it would suggest your relay is faulty.

You might find this posting helpful as background: View topic: K-jet made easy!!! - The Mk1 Golf Owners Club

The accumulator comes after the main pump, at the rear of the car, before the long run to the fuel filter at the front. I would bypass checking the accumulator for now, and go straight to the fuel pump outlet - crack the banjo and see what comes out - much easier if the car is up on stands or ramps.
To check the lift pump - under the rear seat is a black round cover plate, undo the three screws and lift. You should then see the top of the sender - disconnect the plug, undo the two hoses. Then using a drift or similar knock the outer edge of the sender - there are notches in it, so the sender moves anticlockwise, less than a 1/4 turn and the sender will be released. Ease out the sender and lift pump - it is a very tight fit. Avoid what I did and knock the filter off the end back into the tank if you can. There is a picture of the lift pump and sender here : View topic: Fuel system problem, HELP!! updated 31.7.12 - The Mk1 Golf Owners Club

Lee

on mine i spent ages trackign the same problem, eventually i took the feed lien off the pump itself and observed no fuel coming out. on the off chance i swapped the non-return valve out the end of the pump with one off a mk2 golf pump i had sitting and that fixed it!

LeeO said

To eliminate the FP relay, and aslo to make other tests easier, try this:

As you look at the relay plate/fuse box, the top left relay position is no1 across to no6, and the bottom row is 7-12. There may be some other relays clipped to the top - ignore those. The FPR is in position 2 - it is a very tall relay. Pull it and swap it with the relay directly beneath it in position 7, you have to rotate it by 180degrees so the big contacts line up. Now the FP will run as soon as you turn the ignition on, without having to crank the engine. Don't drive the car lie this as the FP won't cut out in the vent of a crash. As you have established no fuel at the filter (is that inlet or outlet?) turn on the pump and work your way back towards the tank cracking each joint until you get fuel. That should establish whether you have a blocked pipe or not. If the main pump is delivering fuel, you should measure the output over 30 seconds - if you have  pump with screw on electric connections it should be 900cc, if you have push on electrics it should be 750cc. If you are not getting this quantity either the pump is on the way out, or you have a restriction.

Have you physically checked the lift pump - modern fuels have more ethanol which attacks the rubber hoses inside the tank, the one that connects the lift pump to the sender - look for black gunge! Also check that the lift pump filter is in place and intact - I have found that sometimes they come adrift.

good luck
Lee

Hi,
Do you mean swap with position 8?
8 is directly underneath 2 with a relay with the number 17 on it. should I swap it with this one?
 position 7 is currently  empty.
and can you confirm if I am putting the relay i remove from position 2 into the position i remove the other one from? or can i just keep relay 2 out for the test?
cheers
KP

yes put the 17 relay in slot 2, this should bring the fuel pump on with ignition. wipers and blowers wont work with the 17 relay removed tho just FYI

dont put the fuel pump relay in any other slot just leave it out for the tests

great thanks.
Just done that and turned ignition to ON. - still no fuel reaching the filter inlet. I can hear the pump.

So i guess the relay is OK.

Is this telling us anything new?

Now going to try to get the hose off the pump inlet from the tank.
 

this tells us the fuel relay isnt the problem at least. its worth leaving this relay in for now though as it makes troubleshooting way easier

some tips on checking the tank & fuel pump etc for issues. in addition the post-84 cab/rocco lifter pumps have a wee mesh filter on the end plus as above the rubber pipes could be damaged:
View topic: Fuel Tank cleaning *HowTo* clear that blockage - The Mk1 Golf Owners Club

Thanks for all your help guys,. Made some progress, so here's an update:.

Removed inlet to main pump under the car and no fuel coming out of the tank to the main pump. Done some electrical tests around the lift pump connection and appears no power getting to lifter pump. Anyway, removed the rubber hoses and removed the lifter pump out of the tank completely. then connected the battery directly to the pump connections  - looks like the pump was somehow 'stuck' as doing this somehow kicked the lift pump back into life - lift pump now coming on. Put the lift pump back into tank and reconnected all hoses and returned Relays back to where they should be. Car is now starting first time. Which is great.
However, there was fuel pouring out of the fuel lines under the engine. Closer inspection pipes look corroded -  so it looks like I need new fuel lines.
Also noticed some rust in the tank - probably coming from the corroded fuel lines maybe? the tank and filler neck were all replaced about 5 years ago and still look clean.
Another thing I noticed is the lifter pump doesn't have any strainer attached to it. and it isn't in the tank - Does that mean its been installed without a strainer attached? do they come without strainers? should I get a new lifter pump too with strainer? See image:








Anything else you think I should be replacing? or cleaning? at this stage before driving again?

thanks again guys.

That is a Vane type Impeller, if the screen fell off and it sucked up a bit of rust, then the Rust would cause the impeller to bind…..

A trick to keep the filter on the pump as you install it is:




Then before locking it in place, snip one side and pull it off.

Briano1234 said

That is a Vane type Impeller, if the screen fell off and it sucked up a bit of rust, then the Rust would cause the impeller to bind…..

A trick to keep the filter on the pump as you install it is:




Then before locking it in place, snip one side and pull it off.

Great tip!

And managed to find the strainer in the tank - hopefully no lasting damage to lifter pump.

I'm gonna clean out the tank over the weekend.
Ordered new flexi fuel lines too. so I'll get it all cleaned up and ready to go.

cheers all.

KP

Make sure the filter is a tight fit on the lift pump. I found mine had got slightly loose so tended to fall off very easily. I used a slice of fuel hose to wedge it on more tightly.

I would also stick a new fuel filter on (the one in the engine bay) after changing the fuel lines and then change it again in a 1000 miles just to make sure it's collected all the rusty bits as you don't want rust etc getting past the main fuel filter.

Agreed. Avoid the Crosland filters from ECP. These are better: http://www.vwspares.co.uk/g1filters.php