Fuel rails getting fuel but not at pressure ALH

[Ian Keeffe]

Hey all, I’m new here. I just bought an 2002 mk4 golf with an alh engine. It was sold to me not running with a dealership diagnosis of bad injection pump. I did everything to check their diagnosis and it seems they were correct. It wasn’t getting anything out of the rails or moving fuel around at all in the lines to and from the filter. I put in an 11mm pump and now it is moving fuel in those lines but the fuel pressure in the rails is not enough to spray at all. It just bubbles and seeps out when cranking. What could this be? Yes the pump is primed correctly. I took out the pressure release valve and it moved freely. The glow plug light comes on and my scanner interfaces fine so I don’t think it is relay 109 related. Vcds tool is in the mail. The only other thing is that the oil pan was cracked when I had it deliver to my house. I’m putting a new one on today but maybe the engine is cutting fuel because of low oil? It hasn’t leaked that much out though and doesn’t have an oil light coming up.
I would love to hear any inputs yall have!

 

[oilhammer]

ECU doesn't care about the oil, so that isn't it.

Is this an actual new/rebuilt pump? Used? From where?

Does the ECU see cranking RPM on scan tool data? Is the belt installed correctly?

 

[Ian Keeffe]

It’s used. The previous owner bought it but never installed it. He said he got it somewhere like eBay where it was presumed to be good. This would have been in 2022.
Thanks

 

[Ian Keeffe]

I’ll check the ecu seeing rpm in a bit. As well as look at the filter under the solenoid (I’m suspect of that). Belt is installed correctly.

 

[oilhammer]

If used pumps sit, they can have internals that stick and don't work properly.

 

[Ian Keeffe]

Is there any solution to that or is it just get a new one?

 

[Ian Keeffe]

Okay, the ecu is seeing rpm. I tried it with the guts of the solenoid removed and it was about the same. Does this mean the quantity adjuster is way out of wack or not working or that the internals of the pump are snapped or what?

 

[csstevej]

I see that you replaced the injection pump .
Did you use the correct tools to set static timing correctly?
Did you fully bleed the fuel system using a mity vac or equivalent sucking on the return side of the pump….can take awhile.
You can also hook up an external fuel bottle hanging it off the hood latch like an IV bottle to give you some head pressure to the pump to help bleed it.
Crack the injector lines at the injectors and wrap with rags and crank the engine till you get a good fuel flow the tighten them up and see if it will start , if you got good fuel to the injectors and a glow plug light with rpm’s showing then it’s a timing issue.
If you used the correct lock down tools when you changed the IP the car should start if bled correctly.

 

[Ian Keeffe]

Did you use the correct tools to set static timing correctly?
Yes

Did you fully bleed the fuel system using a mity vac or equivalent sucking on the return side of the pump….can take awhile.
Yes

Crack the injector lines at the injectors and wrap with rags and crank the engine till you get a good fuel flow the tighten them up and see if it will start , if you got good fuel to the injectors and a glow plug light with rpm’s showing then it’s a timing issue.

I cannot get fuel to get into the fuel rails. If the pump is indeed not broken is there something electrical that would make the injection pump not pump? I am going to get vcds and look at all my inputs to the quantity adjuster

 

[csstevej]

When you turn the car on…. Do you hear the fuel shutoff solenoid click?

 

[csstevej]

You should get momentary power to the solenoid for it to open , if the car is not cranked it shuts off….say couple of seconds of power give or take.

 

[Ian Keeffe]

I bench tested it and it tested fine. It was getting 9v when I tested it while cranking a couple days ago. The battery was pretty dead so that isn’t too far off.

 

[csstevej]

Do you have a battery charger connected to your battery while attempting this?

 

[csstevej]

I’m still thinking you have an air pocket in the pump…… they can be a bear to bleed….

 

[Ian Keeffe]

Yes, it’s not amazing quality though. I have attempted to bleed the lines with another car “jumpstarting” it with no luck either.
I have pulled through enough fuel to where my harbor freight vacuum tools resivoir has needed to be emptied twice. I have tried starting it with the solenoid removed and could see that when cranking fuel is moving from low pressure to high pressure side

 

[csstevej]

Try hanging a container of fuel like an IV to get some head pressure on the fuel while cranking…..its a wag , but might help.

 

[Ian Keeffe]

Okay I’ll try that. Here’s what the dealership said about this back when it broke. The guy I bought it from didn’t really know what he has doing he wanted to fix it and not pay the dealer. He tried everything but the pump because he didn’t believe the dealer but did order a used one which is the one I put in it now. It’s an 11mm. Theres a lot of things the dealership tried written here.

IMG_7076.jpeg

• Ian Keeffe
• Mar 1, 2024

IMG_7077.jpeg

• Ian Keeffe
• Mar 1, 2024

 

[oilhammer]

I use a 12v electric pump... one salvaged from a CJAA (the auxiliary pump under the hood). It works FANTASTIC to prime VE and PD cars.

 

[KLXD]

You don't get a huge amount at the injectors. It won't really squirt unless you have the nut cracked just right.

 

[Ian Keeffe]

Oh that’s good to know. Thats kinda what I was wondering about. So if I opened it too much it would just come out and not spray?

 

[oilhammer]

When it is getting enough to start, and you have them cracked loose, they'll spit high enough you can see it from the driver seat.

 

[Ian Keeffe]

Okay so now there’s conflicting info. If I opened it two whole turns, should it spray up more than one inch?

 

[oilhammer]

Like 10+ inches, easily. They'll "spit".

 

[oilhammer]

Seriously, go get a cheap 12v inline fuel pump:

Google Search

www.google.com

Plumb it in temporarily between the filter outlet nipple and the pump inlet nipple. Turn the key on. With all the lines cracked loose about 1 turn at the injectors, power up the pump.... as soon as you see fuel starting to dribble out around an injector, tighten that pipe up. Sometimes it is just one at first, sometimes you get lucky and it is two. Turn the power to the pump off, and crank the engine just enough that the injection pump rolls over to a different cylinder. Repeat the process, and as soon as you know you have fuel coming out of at least three pipes, tighten them all down, remove the pump, put the fuel hoses on as normal, then crank the engine with the accelerator pressed about halfway down. When the engine starts to stutter, keep cranking it until it will run on its own. With this method, it usually takes very little effort.

 

[Ian Keeffe]

Okay I got one on amazon should come tonight. It’s 3-6 psi hopefully that’s enough

 

[oilhammer]

That's plenty... there is normally no pressure on that side anyway, just slight suction. The injection pump itself has TWO pumps. It has a small delivery pump in the front (belt) end, and that is all that it has to pull the fuel all the way from the tank through the filter into the pump housing. Then it passes the fuel into the rest of the pump, with most of it just being used to cool/lubricate everything and sends it right back out to the filter (for preheating) and when the thermo-tee is warm enough, all of it goes back to the tank. A small portion of it gets pushed into the actual injection pump where it gets sequentially injected into the engine to make it run. And each injector sends the excess back to the return circuit (the little braided hoses).

If that suction pump is dead, the pump is dead. It won't work. A used pump can be a gamble if it sat for a while. I would never go through the effort to install a used pump unless I pulled it off another running car myself, and either put it right back on another engine OR filled/sealed/stored it appropriately. Otherwise a used pump to me is nothing more than a core.

 

[Ian Keeffe]

Yes, I can tell that the suction pump is working because I can watch fuel flow in the delivery and return line when cranking. I can also remove the solenoid and see that fuel is getting pushed into the this section from the suction/delivery pump

 

[oilhammer]

So it may just be that the injection side just doesn't have the mojo necessary to pop those nozzles open.

 

[Rob Mayercik]

I had that happen abruptly on a freshly rebuilt pump a few years ago - the high pressure end failed out of the blue, had the pump warrantied.

Sounds like you might have to have the pump rebuilt, in which case you might as well have the 11mm pump done - if your car is an automatic that's what it had in the first place, if you've got a manual the 11mm pump is a slight upgrade.

 

[Ian Keeffe]

I’m gonna be honest rebuilding the pump would be more than I paid for the car. I’m not really willing to put that into a car that I haven’t even seen run yet. What do yall think about pulling one from a junkyard? What is the cheapest viable option