Better way to prime v.e. injection pump

[ghohouston]

So yesterday, as I finished up my timing belt job and injector change, it came time to try and start my car. I started out just cranking the engine with glow plugs out to try and bleed my injector lines with low strain on the engine. After a while, I realized I wasn't getting the fuel spurting from the lines, as usual. I put the trans in 5th with the wheel off of the ground and spun the tire quite a bit with no luck. I then removed the main suction line from the fuel filter outlet fitting, and pulled a vacuum through the filter. Found it has lost quite a bit of diesel from the injector lines being removed, and the car sitting for a few days. I got diesel coming through the filter quickly as expected. So go back to the mentioned methods of priming with no luck. I then removed the #4 injector return line to the pump, and pulled vacuum through it, for like 20 minutes, with no luck. Even spun the tire again while vacuum was being pulled, and this still didn't do much.

At this point, I said there has to be a much better way. I removed the 17mm nut off of the return fitting on the injection pump, removed the return banjo fitting that the #4 line tee's into, and finally removed the banjo bolt fitting from the pump. With the banjo bolt fitting removed, I found exactly why these cars are so hard to prime this way. That fitting has a check valve in it, as well as very small orifices for the return fuel. I then took a piece of 3/8 fuel line cut straight, and just stuck it up against the threaded return port of the pump, and pulled vacuum through it. I had the pump primed almost immediately.

Short version, for easy injection pump priming, remove the 17mm nut off of the return fitting on the end of the pump. Then remove the banjo fitting that is connected to the return lines. Then remove the actual banjo return fitting bolt that goes into the pump. This is the 17mm hex just against the pump housing. Then pull a vacuum through this. Fuel will come very quickly, compared to the rest of the methods I've found on these cars.


Figured this could help save many many people hours of headaches. I wish I would have taken pictures.

 

[oilhammer]

I use a standalone 12v pump, run off the battery. Just takes a few seconds, and VROOM, it starts right up! No cranking, no fuss, no headaches.

 

[ghohouston]

I get that is an alternative as well. Almost all the posts I see on here about priming the injection pump, suggest pulling vacuum through the return fitting, and as noted, that way takes forever. I wanted to give an easier option.

 

[flee]

When I did injectors along with a freshly rebuilt IP all I needed was
my trusty HF MityVac clone pulling fuel through the return line.
I doubt it took more than 5 minutes.

 

[hey_allen]

I used a hand vacuum pump on the return port as well, with no particular issue.
The only time I've had to do this (other than when I installed a new 11mm pump!) was when I forgot to prime the filter before firing the car up after a filter change, and ran the pump dry before it could prime the new filter.

 

[PakProtector]

I had some issues with my son's ALH; it would not prime. Matter of fact it was impossible to draw fuel through the IP with a hand vac. I gutted the pick-up's check valve and all those issues went away. It primed easily by sucking on the pump's return line, and it has never given a lick of trouble since.
cheers,
Douglas

 

[ghohouston]

I'm sure there is a seal sucking air somewhere, which is why I had so much trouble. Again, just wanted to pass the info along, because the way I describe was almost instant

 

[Genesis]

Yeah, I stick a pump between the tank and the intake of the filter with alligator clips that goes to the battery. Crack an injector, power the pump, you'll get fuel almost instantly. Snug up the injector nut and it starts.

That way there's no risk of unfiltered fuel getting into things either.

 

[ghohouston]

Not everyone has an electric fuel pump laying around either. I have one, but it does 60 p.s.i. and seems to me may damage the seals in the pump, but I do agree that way should work as well if one has a low p.s.i. pump. I definitely agree unfiltered fuel should not be used. Pulling through the return still filters the fuel as well.

 

[scurvy]

I get what you're doing here, but I also haven't had a problem with my hand Mity Vac pulling vacuum on the return port to prime a VE pump in the past. It's not instant by any stretch of the imagination, but it works. A couple minutes with occasional pumping to keep vacuum up and it's good to go.

 

[BobnOH]

I've only done 2 IP replacements. Easily purged with a long section of clear hose on the IP out, sucked on it for like 90 seconds. Then cracked 4 injector nuts, rags, crank for like 4 seconds.
But I've read several posts where folks have all sorts of issues getting the air out. Unsure why.

 

[ghohouston]

My pump sat for a couple days while waiting on parts, so I'm certain it completely drained. Also am betting on an old seal or 2 sucking air. I have an air tee fitting I pull vacuum on fuel systems on the excavators i work on all the time, and works like a charm, but this was just ridiculous. I gave up after about 30 minutes or so of pulling vacuum through that check valve fitting.