Best way to prime ALH 10mm injection pump?

As the title states, what is the best way to prime the injection pump? I am putting the head back on now. Last time I had it apart it took me 2 days to phill fuel thru it. Any help is appreciated greatly. I was window shopping trying to find 11mm pumps. I seen a parts kit that said I could make my 10mm pump into a 11 or 12 mm pump changing some internal pump parts. Anyone try this? Any advice on trying it? Thanks again.

Link to the parts kit? Hopefully not sold by Prothe. Use a Mityvac. Pull fuel through the return line on the pump. Once you've gotten most of the bubbles out, crack an injector line and crank until fuel sprays out of it. Do it to the next 3 injectors. Should fire up right away after that.

pick up a small marine bleeder bulb, put it between filter and tank (feed line), loosen return banjo and return fitting, pump bulb until bubble free fuel flows from between QA and fitting, tighten fitting and nut, loosen injector lines @ injectors, crank until fuel squirts, tighten lines, start engine, after engine is running smooth you can shut it down and remove the primer bulb....using a mity vac on the return can* work but the tiniest air leak upstream (pump, lines, thermal T) or an open/defective thermal T will frustrate your efforts, started using the push method above after several failed and or difficult mity vac attempts on different cars... push method has proven to be very fast and very consistent

Replaced Injection Pump twice on my old A4 TDI.
Used a long clear hose on the pump out, sucked until until I got solid fuel. Cracked all 4 injector lines, rags, cranked it maybe 5 seconds, done.
As much as I love buying tools, and I do, still don't own a mighty-suck. I do have a hand pump with a vacuum gauge, needs that thing.

I just had my A4 pump out for seals.

I sucked on the line from the filter until it was full. Connected it to the pump and sucked on the line from the pump until I got fuel and connected it to the filter.

Started right up after bleeding the injector pipes.

I won't splain the problem I had after this again.

I too have a vacuum pump that I didn't use.

I never had good luck using vacuum to pull fuel from the return. When I did, I got nothing flowing. I resorted to using a low pressure fuel pump to pump fuel from the filter into the pump inlet, and it primed the IP very nicely.

UFO said:

I never had good luck using vacuum to pull fuel from the return. When I did, I got nothing flowing. I resorted to using a low pressure fuel pump to pump fuel from the filter into the pump inlet, and it primed the IP very nicely.

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Seen a lot of these. Never ciphered out what was causing it. Suspect the pump in a certain position was closed for bidnez. Like I said though, only done it twice.
If the pump was not voided, you may get away with just the injector line bleed.

I think it's that fitting/valve on the top cover of the pump. Seems that once fuel gets to it flow really slows down.

But at that point the pumps full so that's when I stop.

I own both a hand powered vacuum pump like a Mity-Vac and I also own a remote engine oil change vacuum thingy you stick in the dipstick hole. The oil change thingy has a three quart volume so I can create a large volume of vacuum before I open the valve and apply vacuum to the return side of the pump head. Sometimes it takes what seems like forever before the fuel starts moving, but it always works and I don't have to keep making vacuum like I do with the hand pump. Once I have solid fuel I remove it, crank the engine for 10 seconds, crack the #3 injector nut, crank again--at this point the injector is solidly squirting fuel--lock down the injector nut and the engine will usually start running at that point.

I have a small inline diesel fuel transfer pump (12V) with wire leads on it. I think I paid $50 for it.

I put it between the tank and INLET of the fuel filter. This way NO UNFILTERED FUEL goes into the pump. Clip on the leads, wait until it stops (when the system is pressurized), crack the line nut on #1 or #3 (pick one; I find #1 works just fine) until you get fuel when cranking, snug it up, it should start.

Then remove the pump. All done, takes more time to put the pump inline than the rest, and it's damn-foolproof. It will also instantly detect air leaks on the suction side (they'll become very evident with fuel leaking out!) as well and thus is very useful.

I'd played with various options for diesels (Mityvac, oil change pump, etc) for a long time and then finally just got tired of screwing around and bought this thing for my toolbox 6-7 years ago. It makes any sort of diesel priming issue a complete non-event that takes less than 10 minutes to resolve.

I just blow compressed air in the fuel fill hole while someone cranks, fires in no time!

jimbote said:

pick up a small marine bleeder bulb, put it between filter and tank (feed line), loosen return banjo and return fitting, pump bulb until bubble free fuel flows from between QA and fitting, tighten fitting and nut, loosen injector lines @ injectors, crank until fuel squirts, tighten lines, start engine, after engine is running smooth you can shut it down and remove the primer bulb....using a mity vac on the return can* work but the tiniest air leak upstream (pump, lines, thermal T) or an open/defective thermal T will frustrate your efforts, started using the push method above after several failed and or difficult mity vac attempts on different cars... push method has proven to be very fast and very consistent

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Generally I pull vacuum through the injector return port, I just put in a pump that had been sitting a year and a half that did not want to prime by suction. Tried this and it worked beautifully, thanks.

Genesis said:

I have a small inline diesel fuel transfer pump (12V) with wire leads on it. I think I paid $50 for it.

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jmodge said:

I just put in a pump that had been sitting a year and a half that did not want to prime by suction. Tried this and it worked beautifully, thanks.

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How much psi is that transfer pump?
I went onto ebay and the transfer pump psi range from low, less than 1 psi to over 10 psi.

I used Jimbotes idea in post #3, I have a ball hand pump I use to fill the boat from a can

The only way I have ever had any luck is to suspend a funnel from the hood with an inline filter feeding the pump. Crack the lines and crank until there is fuel at the fittings then fire it up.

I just primed a dry (Bosch reman pump swapped in) using a Mity-Vac on the outlet fitting on the top of the pump.
It took a bit (LOT) of pumping to get fuel up through the case pressure regulator check valve in the pump lid, but once I did, and then purged the injector lines, it fired right up.

Never had an issue using a cheap vacuum pump. Two things:

1) i wouldn't put anything between the filter and the pump unless I knew it was 100% clean.

2) using the vacuum method made it very easy for me to realize that I destroyed my brand new head o-ring while tightening the bolts and needed to re-do the whole job a second time. Might not have been that obvious, pushing fuel into the pump.

snakeye said:

i wouldn't put anything between the filter and the pump unless I knew it was 100% clean.

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i don't think anyone is advocating putting anything between the filter and pump... my method pulls from tank and pushes through filter

crawdaddy said:

How much psi is that transfer pump?
I went onto ebay and the transfer pump psi range from low, less than 1 psi to over 10 psi.

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I got a 12v one from OReillys made by Edlebrock for about $50. It was designed to be a fuel pump for an engine. Probably around 3psi. or something

I now have it stored in my spare tire area with a 17mm wrench, a pair of pliers, and a 1.5 ft 5/16 fuel hose. Nitrile gloves too.

jimbote said:

pick up a small marine bleeder bulb, put it between filter and tank (feed line), loosen return banjo and return fitting, pump bulb until bubble free fuel flows from between QA and fitting, tighten fitting and nut, loosen injector lines @ injectors, crank until fuel squirts, tighten lines, start engine, after engine is running smooth you can shut it down and remove the primer bulb....using a mity vac on the return can* work but the tiniest air leak upstream (pump, lines, thermal T) or an open/defective thermal T will frustrate your efforts, started using the push method above after several failed and or difficult mity vac attempts on different cars... push method has proven to be very fast and very consistent

Click to expand...

Do you keep the marine bulb in-line permanently, like on an outboard, or do you remove it after it's primed?

Pointman8 said:

Do you keep the marine bulb in-line permanently, like on an outboard, or do you remove it after it's primed?

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I would not. In fact, I would suggest you get a mitey-vac. I mainly use that to prime the pump from the return side if I don't use a pressure pump.

It's useful more than just being able to draw fuel through the system (and that's of course the main goal). If you attempt to prime the system and you notice it's not holding a steady, yet slowly, dropping amount of vacuum as the fuel makes it way into the pump, but instead it drops really fast, then you can suspect a leak of some kind. Leaks can be not as severe to allow fuel to leak, but air can leak in. This will prevent you from being able to prime the system. At least you will know right away about what is happening.

Another indicator is the vacuum stays on, but doesn't slowly drop. This is because there can be a restriction in the line or in some ways. You can troubleshoot further. All in all, the mitey-vac kind of system is useful beyond simply applying suction. You can also use it to troubleshoot vacuum line problems too.

Pointman8 said:

Do you keep the marine bulb in-line permanently, like on an outboard, or do you remove it after it's primed?

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remove it after the engine fires and has stable idle.