Bleeding Air, Priming Injection Pump

[stevyg]

I am having an absolute mare here
After rebuilding my Mitsubishi 4D55 2.3 TD engine, last Saturday I started it up for the first time, the engine was a bit noisy at first until the oil got pumped around, after 2-3 mins it got smooth. I let it get up to temp and ran it for around 10 mins.

I shut the engine off after letting it get up to temp, to take it for its first run. I lowered it off the jack stands, went to start it and now it won't start. It fires up when I put some starter fluid in the air box so I know its a fuel issue. I checked the power plug on my injection pump and I got 5.3v across 2 of the terminals so I *think* its getting the right power (everythings 6V because its old).

I thought it must be airlocked. So I loosened my bleed screw on my fuel filter, and started pumping my primer......after a few attempts I had fuel/air coming out my bleed screw. All good.

I pumped until no air was coming out, just a steady stream of fuel and I tightened the bleed screw back up.

I then started pumping to fill the injector (it says in the book after you tighten the bleed screw, to pump until the primer gets hard/firm) but I pumped and pumped and pumped and the primer wouldn't get firm at all. Took my bleed screw loose and just fuel came out so I know I'm not sucking air in. At intervals I turned my truck over for 10 seconds with my fuel injector line loose and no fuel was coming out of it.

I loosened the screw in the metal supply line going into the injector, I pumped the primer and fuel is coming out, so I know fuel is entering the injection pump.

I tightened that back up, pumped some more and still no firmness.

After some deliberation..I took the fuel return line off the fuel rail and when I pump the primer, fuel is coming out of that pipe (from the injection pump)...is that meant to happen?? I blocked it off with a screw, to cap the hose and I had to take the other side of the return line (going from the injection pump to the fuel tank) off and put another line with a screw capping it off, on there.

With all the exits (return lines) blocked, I started pumping and the return line from the injection pump to the fuel rail with the screw capping it off, ended up splitting (its old) because of the pressure (although the primer still wasn't getting firm) and fuel was dripping out, so at this point I give up for now to ask a few questions.

-Is the fuel meant to come out of the injection pump and into the return lines when you pump the primer?
-Is my timing messed up? (all my marks line up) I don't see how this would make a difference to priming the injection pump and the other problems I'm having.
-Is my injection pump messed up? (its probably 15k miles old)
-Or is there some other problem that I'm over looking?

Thanks for any input/advice

 

[stevieturbo]

So it did actually start the first time and run ?

The hand pump should get hard, so if this doesnt happen it could mean a leak, or air, or a fault with the hand primer itself.

You could rig up a temporary fuel supply, say a funnel and a hose and gravity feed the engine pump. This way you would be sure there is no air and no chance of drawing air. If you can get the engine to run like that, then you know the issue is before the engine.

When you say a fuel rail, is it some sort of common rail diesel ? You said it was an old engine ?

 

[stevyg]

There's a rail that is the return line and connects the injectors, that's what I meant. It's about 30 years old.
I know there's fuel getting to the injection pump but its going straight to the return lines instead of the injectors, that seems to be the problem and why the hand pump won't get hard, it's just pumping fuel back to the tank. It's a Bosch VE injection pump.

 

[stevieturbo]

I'm not overly familiar with diesels. But that sounds like a pump issue.

There is normally a bleed off the injectors and return to tank...via the return from the pump. So something must be stuck open if it's allowing you to manually pump straight out the return. Can you undo the main feed solenoid from the pump, and any return fitting on it ? In case something has jammed it open ?

Gotta love google, maybe some of these might shed some light ?

http://www.dieseltruckresource.com/dev/showthread.php?t=231863

http://www.cs.rochester.edu/~jag/vw/engine/fi/injpump.html

 

[stevyg]

I think the plunger is stuck. Any ideas on how to unstick it without taking the whole pump off?

 

[stevyg]

Well I ended up taking the pump off and taking it apart, much to my annoyance because I had just bolted everything together and set the timing. The Fulcrum lever pin was broke off. From what I can tell, the lever is controlled by some sort of electro magnet and goes back & forward with the pin against the notch you see at the end of the plunger plate. Pins broke, so no plunger movement. Ordered the part today so it should be here tomorrow.

 

[stevieturbo]

Diesels are the work of the devil ! lol

 

[stevyg]

A major pain in the rectum. Hopefully I can get everything together and it works after this.

 

[Antoin]

Bosch pump by the looks of it. Ive never seen that part break on one of them.
The plunger will still move in and out as it should but the (fuel) control collar will just be floating because of that little bit broken meaning no control of fuel at all.

Google "Bosch VE Pump Rebuild" and you will get a great step by step guide to rebuilding it.

 

[Antoin]

http://www.brick-yard.co.uk/forum/ve-injector-pump-rebuild-in-colour_topic17456.html

 

[stevyg]

Thanks for that. They canceled the order on me. I'm having a hard time finding this part. Its a Zexel part and Bosch or Zexel don't make them anymore. The guy at the dealership near me said the last time he sold a part for this type of pump was 1992! Been phoning around to try and find someone that has one in stock but no luck thus far.

 

[Antoin]

Il have that bit in a id say if you to come have a look?
Up in portstewart

 

[Antoin]

Feck sorry I see your in america lol

 

[stevyg]

I'm heading to a diesel shop in town where a guy has 2 old cores in stock. He said the part number on their levers is different but he thinks they will still fit my pump so I will see. If not, and you have that part anto 306 I will happily buy it off you if you don't mind sticking it in the post?

 

[Antoin]

No problem stevy get me a pic of the part and il compare it to what I have.
Those little bits can be interchnged anyway I think.

 

[stevyg]

No problem stevy get me a pic of the part and il compare it to what I have.
Those little bits can be interchnged anyway I think.

I think they can be. My plunger ring thing was stuck on the shaft so I used a pulley puller to get it off. Looks like a bit of dirt got under there and its scored so I'm thinking I need a new head rotor as well as the lever. TBH I think I would be better getting a new core and transferring the parts over. Its a VE4 with a 10mm plunger and right rotation. The pump shop is going to ring me today with a quote to fix it, he said will be over $1k which I don't want to spend on it. Any idea where I could get a core? Do you think a machine shop could polish or take a thousandth off the plunger shaft and the pump will still pressurize the fuel ok?

 

[Antoin]

No it wouldnt work at all as the collar wouldnt be the correct fit on the plunger...it would be useless.
If you can get your hands on any bosch pump with the correct rotation then it will work.
You could have a 9mm, 10mm, 11mmm or even 12mm and as long as you have the associated head, plunger and collar then itl work perfectly.

The bosch pumps came on ****loads of cars, vans etc.

By right rotation do you mean clockwise?

 

[Antoin]

Try vw gtd forum there are loads of veedub heads on it and most are north american or canadian so they could maybe help with sourcing one over there?

 

[stevyg]

Try vw gtd forum there are loads of veedub heads on it and most are north american or canadian so they could maybe help with sourcing one over there?

I had a look but I have a few questions. First of all, I had no idea the heads were interchangable. So I could buy this http://www.ebay.com/itm/BOSCH-04604...395?pt=LH_DefaultDomain_0&hash=item20d3fc5703 and take the rotor head off and it will bolt onto mine? I think this is an 11mm one. Though there seems to be different pumps for Mitsubishi, Isuzu and Nissan - not sure what would be different.

I remembered to take some pics, I know you asked for some earlier.
Heres my replacement (used) part and my old (broken) part

Heres the plunger thats scored, you can barely feel it but theres a burr on one of the edges.

The collar inside scored, sorry I couldn't get it to focus any better.

Do you think I could touch it with my rotary tool to polish the scores on the plunger and the inside of the collar and everything be ok?

A note to any diesel people: I had to use a pulley puller to get the collar off the plunger because it was stuck on so tight. When I pulled it off, I seen what caused the problem. A speck of dirt! A tiny grain of dirt got under there and siezed the collar on the plunger so when the lever pressed against it, the pin on the lever broke. Just shows how much damage such a small piece of matter can do. I put a brand new fuel filter on 10/15mins before this happened too but I must have got dirt in the lines when I was putting them back on again. I have ordered 2 small in-line filters which I would recommend to anyone. This pump rebuild is a PITA.

 

[stevyg]

No it wouldnt work at all as the collar wouldnt be the correct fit on the plunger...it would be useless.
If you can get your hands on any bosch pump with the correct rotation then it will work.
You could have a 9mm, 10mm, 11mmm or even 12mm and as long as you have the associated head, plunger and collar then itl work perfectly.

The bosch pumps came on ****loads of cars, vans etc.

By right rotation do you mean clockwise?

Yes right rotation BTW

 

[Antoin]

That ebay pump you linked is a 9mm plunger and seems to be the correct rotation, the "R" on the serial number denoting the rotation if i recall correctly.
The 9mm will work fine you just will have less diesel going in at point of injection per stroke compared to a 10mm. This can be overcome by increasing the max fuel (screwin her out lawd!).
Itl be fine on a daily driver.

With regards the collar and plunger.... it is scrap from the looks of it they require such tight tolerances.
However it may work with limited efficiency. The collar covers the hole "spill port" when on the accelerator which means the diesel has nowhere to go except ot the head and into the injectors.
If you have any leakage past the collar due to poor fit then you wont get the full benefit of closing the spill port ie you might never get the maximum fuel required.

 

[Ge0rge]

My plunger ring thing was stuck on the shaft so I used a pulley puller to get it off. Looks like a bit of dirt got under there

tee hee.......

sorry school boy humor il never grow up.

 

[stevyg]

That ebay pump you linked is a 9mm plunger and seems to be the correct rotation, the "R" on the serial number denoting the rotation if i recall correctly.
The 9mm will work fine you just will have less diesel going in at point of injection per stroke compared to a 10mm. This can be overcome by increasing the max fuel (screwin her out lawd!).
Itl be fine on a daily driver.

With regards the collar and plunger.... it is scrap from the looks of it they require such tight tolerances.
However it may work with limited efficiency. The collar covers the hole "spill port" when on the accelerator which means the diesel has nowhere to go except ot the head and into the injectors.
If you have any leakage past the collar due to poor fit then you wont get the full benefit of closing the spill port ie you might never get the maximum fuel required.

You've taught me a lot man thanks!

So does the collar actually move back and forward on the shaft? Or does it rotate? Or both? And how tight should it be on the shaft? I can hardly get it to move by pushing on it, I'll probably need to tap it on the work bench or something to get it on. Is that correct?

 

[Antoin]

The collar moves back and forward on the shaft/plunger.

The plunger spins in time with engine and fuel escapes out of the pump head along the channels in the plunger. Each channel relates to a specific injector.
The plunger spins within the control collar which moves back and forth covering and uncovering the spill port depending on how much throttle you want.

 

[Antoin]

With a bit off diesel the collar should slide on the plunger with minimal force. Shouldnt need to be tappin it.
It should slide freely by hand up and down the,plunger