Injection pump leaking, any ideas?

Technical questions and answers concerning all models of VW diesel vehicles.

Moderators: Fatmobile, 82vdub

User avatar
libbybapa
Turbo Charger
Posts: 2446
Joined: Thu Nov 17, 2005 1:05 am

Post by libbybapa » Fri Jul 07, 2006 3:21 pm

EDIT: Read through the rest of this thread or this may very well not work. Okay, I did it on the bench. The process looks very straightforward, but would need to be performed systematically or else disaster might result. Here is the process I would take. The scariest issue IMO is the cleanliness issue. Any particulate in the pump head could be really disastrous for the pump or injectors. Cleanliness is more important than godliness in the diesel injection system.

1. If possible, take the car to the carwash or use a home pressure washer to thoroughly clean the pump head and injector lines. Short of the pressure washer, take out the toothbrush and start scrubbing, especially focusing on the seam of the pump body to head.

1.5. EDIT: Rotate the engine by hand so that the injection pump plunger is not being pushed by the camplate (90° crank after TDC). You can remove the timing hole bolt from the center of the pump head and measure using a dial indicator to find when the pump plunger is not moving.

2. Remove the injector lines and use tin foil to seal the injector bodies, lines and the check valves in the pump. I would go so far as to wrap electical tape around the perimeter of the tin foiled check valves, so that when the o-ring is being replaced it doesn't get damaged on the tin foil.

3. Remove the cold start cable, the rear pump mounting bolt, and the rear mounting plate from the pump head. Replace the two torx (30) bolts in the pump head but loose. Remove the center timing plug bolt. Install a short spacer and retighten the bolt down. Loosen torx bolts a small amount (1/4 turn each) and tighten the center bolt down a similar amount. Gradually work back and forth between the torx bolts and the center bolt loosening the torx a little, tightening the center one a little. When flush, the bolts are inserted clost to a 1/2" so there should be plenty of threads still inserted into the pump to keep the bolts from falling out.

4. Keep going with that procedure until the o-ring is visible. Clip the old o-ring off the pump head.

5. Stretch the new o-ring around the pump head. Remove one torx bolt and slip the o-ring into the channel in that area. Replace the bolt to the same depth as the others and remove another one. Slip the o-ring on the next bit, replace bolt, remove the next one, etc.

6. Once the o-ring is in place tighten down the two torx bolts a little at a time while you loosen the center bolt a little at a time. Remove the two torx bolts that do hold the plate on. Install the plate. Install the pump mounting bolt and cold start cable.

7. Remove tape and foil and reinstall injector lines tight to the pump, but loose at the injectors. Have someone crank the engine over while you watch for fuel at the injectors. When fuel is squirting from the lines at the injectors, tighten them down.

8. Start the car. It may run rough for a little bit while any remaining air is being bled from the pump and lines.

9. Check for leaks or untoward sounds coming from the pump or injectors.

10. Enjoy your favorite malt beverage Image to celebrate your success and the fact that the dealership would have charged you for a *new* pump and the labor to replace the unit. :roll:
Last edited by libbybapa on Wed Dec 20, 2006 10:02 pm, edited 2 times in total.

User avatar
libbybapa
Turbo Charger
Posts: 2446
Joined: Thu Nov 17, 2005 1:05 am

Post by libbybapa » Fri Jul 07, 2006 3:57 pm

As an aside, I once had a pump spring a leak there due to the fact that a slight blockage had developed at the tank end of the fuel return. I finally figured that out after repairing several successive leaks. You might try removing the return line and blowing through it just to assure that there is not any blockage which would cause excess pressure to develop. Cheers.

Syncronaut
Glow Plug
Posts: 24
Joined: Wed Apr 19, 2006 11:08 am
Location: Columbus, Ohio
Contact:

Post by Syncronaut » Sat Jul 08, 2006 9:44 am

Libbybapa, you are the man! Thank you for your effort and for taking the time to test this for my and the rest of the groups benefit. Kudos!

I will give this a try tomorrow afternoon and report back on my success. Thanks for the tip on the return line. Since this happened unexpectedly, it could have been the trigger.

Yum, I can almost taste the celebratory tasty malt beverage :D

Brett
Brett Fairbanks
'91 Jetta Diesel
www.fairbanksmotorsport.com

Asymtave
Diesel Freak
Posts: 174
Joined: Sun Jul 03, 2005 3:48 pm
Location: Fremont, OH

Post by Asymtave » Sat Jul 08, 2006 1:19 pm

Thanks for the write-up Andrew. I personally would never have thought to do it that way. I would have taken the head clean off and struggled to get all the bits put back right.

One comment - I wouldn't use a screwdriver to pry the two apart. The aluminum housing is just too easy to damage. Try to find a piece of brass round stock and hammer it to a useful shape, if at all possible.

Eric
81 Pickup
91 Eco Jetta

User avatar
libbybapa
Turbo Charger
Posts: 2446
Joined: Thu Nov 17, 2005 1:05 am

Post by libbybapa » Sat Jul 08, 2006 1:50 pm

It was actually kinda fun to work out the process. Brass might be better, but the head and pump shouldn't be hard to seperate, and neither surface is acually a sealing one and so not really critical. Certainly it should not require any considerable force and if it does, then a screwdriver wouldn't be the best tool for the job. The whole process is not actually hard, and if done correctly the only risk is particulate contamination. Cheers.

Andrew

Fatmobile
Global Moderator
Posts: 7413
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa
Contact:

injection pump

Post by Fatmobile » Sat Jul 08, 2006 2:14 pm

Thanks alot for checking this out for us.
This is going to save me alot of work in the future. Makes me think of all the extra work I did in the past. Setting that head back on, with the springs in place is alot of work.
I'm going to stick a link to this in my FAQ post.

User avatar
libbybapa
Turbo Charger
Posts: 2446
Joined: Thu Nov 17, 2005 1:05 am

Post by libbybapa » Sat Jul 08, 2006 2:25 pm

I can't remember where, but I'm pretty sure that I read the idea somewhere a while ago, so I can't take the credit for it. I'm glad to have confirmed it as doable. The last time I changed that o-ring I removed the pump and pump head to do so. Yes getting it all back together correctly is tricky and time consuming. Then faced with the reinstall and then retiming of the pump, all in all the time savings for that particular leak is absolutely incredible, and I believe, if done cautiously there is less risk in that the pump remains primarily assembled correctly.

Andrew

Iain
Cetane Booster
Posts: 25
Joined: Sat Jul 08, 2006 6:57 pm
Location: Bellingham, WA

Post by Iain » Sat Jul 08, 2006 8:16 pm

OK, I just happened to find this thread because the IP on my TD started leaking in the same place (between the cast-iron block and the aluminum body). First, thanks to the people who added their input! Very helpful.

I replaced the O-ring in the way that was described above and put everything back together. It all went smoothly so that was good. I had a hard time getting the pump to prime the lines so I started working on priming the pump.

I used a vacum pump on the return line to prime the pump and that worked OK. - still no fuel to the lines

I removed the solenoid and took out the plunger and the spring. - still no fuel to the lines

I put the solenoid back to gether and re-installed it. - still no fuel to the lines

I removed the return line and cranked the motor. - fuel comes out the return line spigot.

I removed 2 of the lines at the distribution block. - no fuel comes out of there.

I towed the car down the street with it in gear - no runny, no fuel leaky

All I can guess is that something is messed up inside the pump from me pulling the block out even that little bit. Does anyone have any sage advice or wisdom to share?

I am not entierly opposed to pulling this all appart, but I would like to avoid it if possible. I am about 500 miles from home and my girlfriend needs the car to get home. It started leaking while she was visiting me. One interesting bit to add, we have been running B100 for the last few months with no problems, changed the lines over to viton, changed filters regularly, everything was good. She switched to running petro-diesel on the drive over because of limited availability of B100 and then the leak started after ~500miles with the petro-diesel.
84 Jetta TD 400k as of 10/7/06 and still counting!

User avatar
libbybapa
Turbo Charger
Posts: 2446
Joined: Thu Nov 17, 2005 1:05 am

Post by libbybapa » Sat Jul 08, 2006 11:00 pm

If you did not pull the head out farther than necessary, I do not see how anything in the pump would have been disrupted. After I did the o-ring swap on the bench I then pulled it apart and everything internally was appeared to be as it should be. I would make sure that the pump is completely full of fuel. If that didn't do the trick I would actually try running with the in and out lines in a seperate container of clean diesel and see if it will run that way.

Andrew

Iain
Cetane Booster
Posts: 25
Joined: Sat Jul 08, 2006 6:57 pm
Location: Bellingham, WA

Post by Iain » Sun Jul 09, 2006 12:17 am

How can I insure that the pump is full of fuel?

I have used a vacum pump to draw fuel through the return line, and I have removed the solenoid a few times and it's mounting area is full of fuel each time. Is there something that I am missing?

Thanks for the quick reply.
84 Jetta TD 400k as of 10/7/06 and still counting!

Fatmobile
Global Moderator
Posts: 7413
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa
Contact:

injection pump

Post by Fatmobile » Sun Jul 09, 2006 3:25 am

All I can think is maybe you pulled it out too far and the throttle lever disconnected from the control collar.
Although I have a hard time imagining this happening without the springs falling out it could be possible.
Doing it the other way, it wasn't just the springs that had to be lined up, you had to keep the throttle lever ball in the control collar socket.
If this was the case you could probably take the top off and see the problem. The hard part to pulling the top is the springs, the rest is a breeze.
It the only thing I can think of so I'm throwing it out there.
One thing good about having the pump on the bench is being able to turn the gear around a few times by hand to see if it's rotating smoothly... or at all.
I wonder if it matters where the cam plate is sitting when we do this.
With the timing mark lined up the springs are being pushed into the head with more tension. Andrew probably had it with the tension off the springs or the gear would have been spinning back to the point of least tension. It shouldn't matter, just a thought.

Fatmobile
Global Moderator
Posts: 7413
Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa
Contact:

injection pump

Post by Fatmobile » Sun Jul 09, 2006 3:25 am

All I can think is maybe you pulled it out too far and the throttle lever disconnected from the control collar.
Although I have a hard time imagining this happening without the springs falling out it could be possible.
Doing it the other way, it wasn't just the springs that had to be lined up, you had to keep the throttle lever ball in the control collar socket.
If this was the case you could probably take the top off and see the problem. The hard part to pulling the top is the springs, the rest is a breeze.
It the only thing I can think of so I'm throwing it out there.
One thing good about having the pump on the bench is being able to turn the gear around a few times by hand to see if it's rotating smoothly... or at all.
I wonder if it matters where the cam plate is sitting when we do this.
With the timing mark lined up the springs are being pushed into the head with more tension. Andrew probably had it with the tension off the springs or the gear would have been spinning back to the point of least tension. It shouldn't matter, just a thought.

finnbulli
Cetane Booster
Posts: 27
Joined: Sun Jan 22, 2006 3:08 pm

Post by finnbulli » Sun Jul 09, 2006 10:49 am

Theoretically you can have air in the high pressure part when you drew fuel through the return line.
Try to open the screw in the center off the high pressure part a little,(where you adjust the injection time).

If you then open the solenoid the fuel should fill the high pressure part with the air leaking away through the screw opening.


Finnbulli

User avatar
libbybapa
Turbo Charger
Posts: 2446
Joined: Thu Nov 17, 2005 1:05 am

Post by libbybapa » Sun Jul 09, 2006 11:51 am

Okay, I went out and sis some significant investigation with the spare pump on the bench. Houston we may have a problem. Fatmobile, you're right on track with the position of the camplate being of issue.

I don't see how the control collar could be of issue, as the collar will slide on the plunger shaft more than the 1/4" necessary for the o-ring change.

The potential problem I see is that the cam roller shafts are less than the 1/4". If the plunger is at the bottom of the injection stroke, then when the head is removed the necessary 1/4" for o-ring access, then there is the possibility of one or both of the upper cam rollers flopping toward the head and the shaft falling toward the plunger shaft enough to cause problems while reassembling. On reasssembly, the cam roller shaft could then remain lodged between the cam plate center circle and the cam roller housing and cause the plunger to remain at the top of the injection stroke at all times. Not good.

If the pump/engine is rotated so that the plunger is at the top of the injection stroke, then when the head is loosened there is not enough space for the cam roller shafts to move and cause any problems. Another possibility would be to get a bolt with threads of the same size/pitch as the timing hole plug bolt, but considerably longer. The bolt could then be placed in the timing hole and tightened down onto the plunger as the pump head bolts are loosened to keep the plunger and cam firmly pressed againt the cam rollers. Then when assembling the pump, the bolt would need to be loosened while the torx bolts were tightened. The bolt in the timing hole would be more successful and easier if done correcly, but would carry slightly more risk of damaging the plunger if tightened too much or not loosened enough while tightening the torx bolt.

Iain, I would remove the timing access bolt that is in the center of the head between the four injector line check valves/unions. An implement poked into that hole will come to rest on the end of the pump plunger. You can then rotate the engine by hand and see whether or not the pump plunger is moving with the rotation of the engine. A dial indicator with the timing hole adapter would be the best tool for the job here, but for lack of that you might get away with a caliper or even a nail. If the plunger is not moving through its stroke, then pump removal, disassembly and reassembley will be required. If it is moving through its stroke, then you have air in the pump.

Sorry for the inconvenience. Hindsight 20/20?

Andrew
Last edited by libbybapa on Sun Jul 09, 2006 12:04 pm, edited 1 time in total.

Iain
Cetane Booster
Posts: 25
Joined: Sat Jul 08, 2006 6:57 pm
Location: Bellingham, WA

Post by Iain » Sun Jul 09, 2006 11:53 am

So first order of buisness is to loosen the screw (bolt) in the center of the block where the fuel lines bolt in, and then remove the solenoid (or just activate it?) And wait to see diesel come past the threads of the screw?

If that is a no go then I will open up the top. Will it be easy to tell something is messed up in there? And then will it be clear what is needed to put it all right?

Also, I remembered 3 things that might be helpful.

1) I disconected the return line at the tank and pump then blew through it with compressed air followed by my mouth so I assume that is in good condition. Is there another vent on the tank I should be worried about that could be contributing to this leak?

2) There was a good amount of spring tention on the block when I loosened the screws. There was NO prying nessacary.

3) There was a clear crack/tear in the old O-ring that I removed.
84 Jetta TD 400k as of 10/7/06 and still counting!

Post Reply