ALH injector pump seals

[clwhitt]

I think I've read enough to replace the leaking injection pump seals on my 2000 Beetle TDI without getting myself in trouble. But I do have one question about the job that I don't understand.
Everything I've read and watched say to mark the pump so as to get it back together exactly as it was. Looking at the pump it looks to be a simple wrench job: undo the bolts, change the seals, line up the throttle cam and bolt it back together. There does not look to be any adjustment here, the bolts line everything up. Why mark things? Why would a VagCom be required afterwards? What am I missing?
Chuck

 

[oilhammer]

There is most certainly an adjustment there, the holes are slotted. Personally, I would have DFIS properly REBUILD the pump. That way, you know it is as good as new and any worn hard parts inside will have been checked, and the whole thing will have been recalibrated.

And then of course a proper scan tool will be needed to reset the pump timing.

 

[snakeye]

I think without knowing his car's mileage, a new seal may be the proper fix for a leaking seal. Sure eventually if you keep an ALH long enough you'll need to go through a rebuild, but that's a lot of $$$ and downtime.

clwhitt have you watched the dieselgeek videos?

 

[burn_your_money]

The QA has slotted holes. The adjustment is extremely sensitive. Even with marking it you will need to adjust it with Vcds

 

[clwhitt]

Thanks for the replies. I finally got around yesterday to replacing the seals - easy job. I did watch one video, not sure if it was diesel geek or not, but it still did not explain the slotted holes that I eventually found (and then it all made sense). Further, googling "injection quantity" helped me understand what was happening with the ("hammer mod") adjustment.
Though the job was easy, I did make the mistake of marking across the casting seam rather than the sealing area ("dammit, Chuck, pay more attention"!). So when I put it back together, the only reference mark I had was an old yellow paint mark where someone may have done this before. I had to use that, and after priming the system, she started up (with a little hesitation that wasn't there previously). Driving it, though, was the telling moment that the setting was not right, she was gutless where she had plenty of power before. I hooked up my XTool VAG401 scanner and noted that Block 15 had different values than those I read about with the VCDS - my meter shows "mg/H" rather than "mg/str" the VCDS shows ("str"?). Nonetheless, I made some adjustments (yes, it's very sensitive!) that seem to have the vehicle running better, at least at start-up, idle and no-load throttle increases (I did this at work this morning, haven't had a chance to road test it yet). I used the "Fuel Consumption" field as the guide for my adjustments (from ~2.00 l/h to ~1.00 l/h).
With this being my only VW, and 340k on the car, I can't really see investing the $200 into a VCDS system. That being said, I still find the concept interesting. Do I understand correctly that I could have made an IQ adjustment without actually loosening bolts, i.e., through software?
Thanks again for your responses.

 

[clwhitt]

FWIW, that diesel geek video makes it look far more complicated than it really was for doing the two rubber seals (I didn't see the second part, they did reference a third seal).
Using 17mm wrenches, unbolt the return fuel fitting and move it out of the way.
Using the special triangular socket (came with my Bosch seal kit), unbolt the security bolt. Using a Torx T-30, take off the remaining top three bolts.
Change the seal and put the cover back on with the T-30 bolts only.
Using a T-25, remove the small clamp for the throttle cable.
With the T-30, remove the three lower bolts and rotate the quantity adjust body up and forward so you can replace the seal. On reassembly, make sure the cam fitting engages the cam, then reinstall the T-30 bolts and triangular bolt, line up with your previous marks and tighten things down.
Put the T-25 clamp back on.
Prime your pump through the disconnected fuel return fitting hole (I used a 12v oil change pump with a clear hose jammed into the hole, you could do it with a Mighty Vac, or even pour fuel in with a funnel (mind your cleanliness!)).
Reinstall the fuel return fitting.
Crack open the injector lines at the injectors and crank the engine until you see fuel. Tighten up the lines and start your engine.
Then the only complication will be getting the IQ exactly where you need it. If you have the equipment to do it yourself, cool. If not, you can certainly get it close enough to be drivable so you can take it somewhere for that final adjustment.
It may well have taken me more time to write this than to actually do the wrench work.
Easy peasy.