Golf MK4 ALH will not run once I hook it up to fuel filter.

[philipvitale]

I am having an unusual problem. I did a motor swap and once everything was hooked up I usually hook up a line to a funnel and hang it from the hood to prime the IP and that worked fine but then I hooked it up to the fuel filter and it dies. I replaced the pump thinking maybe it was bad and I replaced the fuel filter as well but still no luck. If I keep pouring fuel in the funnel it runs fine. What am I missing here? I also used a mitty vac to suck from the supply side and that was fine, I was getting fuel. The only thing I couldn't do was suck from the return side, I couldn't get any fuel in the cup. Is there a check valve somewhere? It ran fine before I put the engine in, it was just burning a lot of oil. Any help is much appreciated.

Phil

 

[philipvitale]

An update, if I disconnect the return and put it in a bottle it will run. As soon as I attach it to the fuel filter it dies.

 

[afterthisnap]

Same filter?

 

[Vince Waldon]

For sure have the send and return lines hooked up properly at the filter, in both directions?

 

[philipvitale]

brand new filter, I made sure many times the supply and return are right. I tried swapping out injectors and same thing.

 

[philipvitale]

Here is the video of what the return looks like.

 

[Mongler98]

Did you prime the filter?

 

[philipvitale]

for sure, like I said if I hook up the supply and disconnect the return and put it in a bottle it will run.

 

[turbodieseldyke]

Can you push air through the return line back to the tank? Maybe it's clogged.

btw, your yootoob vid is marked "private" and unviewable to the rest of us

 

[philipvitale]

I can try that in the am but I have to think it's ok. I changed the video to public. Thanks for letting me know.

 

[Mongler98]

for sure, like I said if I hook up the supply and disconnect the return and put it in a bottle it will run.

That is not priming. You must draw fuel though it and onto the IP from a vacuum on the return line of the IP not the filter. For quite a while

 

[fatmobile]

So that video was the line coming off the output of the pump,
the line that usually goes back to the tank,
and put in a bottle?
Because I see it's blue and thin.
Maybe include how it's connected to the pump in your video.

You aren't changing the output banjo bolt or anything right?

Also looks like it's spurting and flowing a lot of fuel for idle.
The output banjo bolt has OUT written on it?

 

[philipvitale]

Yes, the supply line coming from the tank is hooked up like it should to the inlet of the pump. All I did was remove the outlet and put it in a bottle. The blue line is just something I added so there is something rigid to put in the bottle. When I hook up the outlet side back to the pump it dies and creates pressure. Even with the clamp on I can see bubbles escaping from the outlet side on the hose. I hope I am explaining this ok. For some reason it seems like there is a lot of air being introduced to the system.

 

[oilhammer]

I'd pull the lines off at the sending unit at the tank, then there is another pair of connections under the car near the tank, by the right parking brake cable, then those lines connect under the hood on the inside of the strut tower, near the coolant bottle. Isolate and check each section if you have to. Make sure nothing got pinched, chewed on (mice), or is leaking.

 

[Mongler98]

I still have yet to be convinced that the filter and IP are primed correctly.

 

[philipvitale]

Here's another update. I plugged the lines at the sending unit and used my mitty vac at the fuel filter and my supply side is not holding a vacuum. How the hell could there be a leak there? That line goes in the frame rail.

 

[oilhammer]

A mouse. It happens. That is exactly where I have seen them chew a hole. Gas and diesel.

The whole assembly slides down and out the bottom.

 

[philipvitale]

Never mind, it does hold pressure. What I was using to plug the line at the sending unit was not a good plug. It does hold pressure. Maybe I'll try another pump.

 

[philipvitale]

Well the third pump worked. I think these pumps sit on the shelf for so long and get old and don't work anymore, kinda like humans.

 

[turbodieseldyke]

Well the third pump worked.

Is there a lift pump in the tank?

 

[philipvitale]

no

 

[DivineChaos]

Post a video for us showing fuel line routing. From the firewall to the filter and which line you have connected for feed and return.