Is it possible for lda starwheel/pin adjustment to cause these major problems? - page 1 - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• Is it possible for lda starwheel/pin adjustment to cause these major problems? by damac on 22 Dec, 2011 17:15
• Long story short is I always wanted to try and adjust these things to take away a darker haze present on my car during boost which didn't clear up.  I had a thread bookmarked with the basics so tried it when doing some regular maintenence.  No issues with car running before I touched things   None of the injectors or pump body, etc. have been changed.
  
  I screwed the starwheel out so now the diaphragm sits above the case and I have to push the lid down to tighten the screws.  And I orientated the boost pin so the less steep angled sign was pointed toward the left, as I'm looking at the pump from the front of the car.
  
  Something was definately off from the get go in that it took me way too long to prime the injectors.  I finally got it to choke to life and waited for the bubbles to clear.  Then I just took it for a test drive and noticed a steady larger thick cloud of whiter smoke that got worse with more pedal.  Engine is running smooth on all 4.  Also its down on power and the boost isn't building like normal.  This reminds me of when I experimented with another pump and turned the fuel screw down, it made the car a wimp that couldn't even pull up a hill in 2nd gear.
  
  Then the car died with no warning down the street.  Got it to restart after 10 seconds.  Drove it 1/4 mile and the car is stuck again on the side of the freeway and ran the batteries down trying to restart, didn't even sound like it wanted to catch.
  
  Would love some opinions, thanks!
• #1 by theman53 on 22 Dec, 2011 17:24
• I would just put it back to where you had it and try again. It shouldn't have that much effect on your starting, but it could. If you want to change something like this do one at a time and remember a little goes a long way. The starwheel seems to limit when boost fuel is dumped, rotating the pin is how much. Stiffening the spring can limit the travel, so fuel could be limited as well, but 10psi working on the 3" diaphram will push it down no matter how tight it is...unless it is coil bound. Which could be your problem.
• #2 by damac on 22 Dec, 2011 18:23
• Quote from: Dieselstink on 22 Dec, 2011 17:40

  Did the little pin that rides on the boost pin fall out?  Any fuel leaking from the little black nipple thingy?
  

  
  This pump was resealed, there is are no external leaks.
  
  As far as that pin, is it possible for that to come out when the top is still mounted to the car???  I had to turn diaphragm to get around that pin and lift up and also fiddled around it to reinstall but you have me paranoid   I am going on a rescue mission soon as its dark.  While the car is being boosted I want to quickly get under the hood and put those settings back and see what happens.
  
  
• #3 by burn_your_money on 22 Dec, 2011 19:37
• The pin can not fall out.
  
  Why did you have the fuel lines off to do this? Any fuel leaks at the injection lines? Maybe one cracked. How's your fuel filter? They like to clog when you are working on other things just to confuse you.
• #4 by guy plain on 22 Dec, 2011 20:05
• what if the pin below the star wheel was pushed in and stuck?
• #5 by damac on 22 Dec, 2011 20:44
• Looking back I think I approached this totally wrong but it didn't click until after the test drive that the power delivery and smoke was drastically worse.  I should have just stopped near home
  
  When I initially pulled the lid and the pin there was fuel in the lower cavity so I just assumed air had to be purged out upon restart.  All lines were untouched then and that is when the starting issues started.  Car didn't sound like it was trying to catch.  No smoke from tailpipe.  Thats when I started testing solenoid, ran lead straight to battery and then cracked the injector lines.  It took me killing the battery 10 times before I saw fuel at each port.
  
  A handfull of times out of nowhere I got the car to start with pedal to the floor and I had to keep it past halfway to keep going.  There were misses,tons of white smoke,  and less than a minute later it would turn off by itself. 
  
  For some reason towards the end all of a sudden I was able to clear it out and let it idle although when I reved and let off it would go lower than it was set and struggle a tad.  I let it warmup to prime system and it was idling ok on its own so thats when I decided to drive it.  Also even with advance on at warm idle I could see a hint of white smoke puffing, although I can't say it smelt like diesel at the pipe?
  
  In the article I was reading it said if you want far back from stock that you would lose power.  Is it possible since things were running well before and I turned it way back that I went too far and it just cannot delivery the fuel right?  Since I just had a constant darker haze on boost before perhaps I should have just went 1/4 turn at a time?
  
  Its sitting like 1/8" higher atleast from where it was at, I had no idea how far to go I was just looking at the threads and guessed and figured the car would tell me whats up, lol.
  
• #6 by R.O.R-2.0 on 23 Dec, 2011 10:05
• sounds like a fuel delivery issue. like a plugged filter.
• #7 by damac on 23 Dec, 2011 16:03
• Ugh I edited after messing with the starwheel some more its made no impact.
  
  It started up initially but within 5 minutes it died.  I was stabbing the throttle and letting off and it went from typical idle to where it was sub 800 and running rough.  No smoke during all this.  Its firing on all 4.  Then I couldn't restart. 
  
  Is it possible to have such restrictions without having bubbles in the in/out lines?
  
  I just let the diesel purge do its thing so wasn't messing with it, I guess I will do the jug thing again and rev it and see what happens, I didn't rev it out at this time, I should have seen if the idle would recover.
  
  Here is a video during the purge.
  http://www.youtube.com/watch?v=Pq6g2sXjPQA
  
  
• #8 by burn_your_money on 23 Dec, 2011 19:57
• Quote from: damac on 22 Dec, 2011 20:44

  When I initially pulled the lid and the pin there was fuel in the lower cavity
  

  
  This means you have a leaking seal in the LDA, which would explain your hard starting. All the fuel is draining out of the pump. Do you have clear lines going to and from the pump?
  
  

  Quote from: guy plain

  what if the pin below the star wheel was pushed in and stuck?
  

  
  You can't put the lid on with the pin out. You also can't push the pin in far enough that it would get stuck. If it did some how get stuck being pushed in it would only limit your max fuel, it would have no effect on idle. It might mess with the starting fuel though. Most likely, if it was moving before, as soon as you went full throttle the pin would be pushed back to where it belongs.
• #9 by damac on 23 Dec, 2011 20:37
• Quote from: burn_your_money on 23 Dec, 2011 19:57

  Quote from: damac on 22 Dec, 2011 20:44

  When I initially pulled the lid and the pin there was fuel in the lower cavity
  

  
  This means you have a leaking seal in the LDA, which would explain your hard starting. All the fuel is draining out of the pump. Do you have clear lines going to and from the pump?
  
  I do and after I get it primed there both clear.   
  
  Just so I am sure here, if you take the cover off and the pin out there should be NO fuel at all that comes up when you pull the pin?  Like it was dry and then I pulled it out of the cavity and it had fuel behind it.
  
  Or that pin is the only thing holding fuel back up there and where its coming from?  I can see it down there, it stops you from pulling the pin up and out initially without turning.  That sucks because it was resealed and the car has been running fine, unless the smoke I mentioned had anything to do with some leak.  No fuel comes from the lda vent.  And up until I screwed with things I can go pop the hood and see fuel primed at the pump.
• #10 by burn_your_money on 24 Dec, 2011 11:27
• Once you pull out the pin with the diaphragm on it, there is another pin that is horizontal. That horizontal pin has an o-ring around it that stops fuel from reaching the vertical pin with the diaphragm on it (boost pin) It's a lot of work to get to that o-ring so depending on who resealed the pump, they may have skipped it.
  
  Once the pump is primed now, does it loose it's prime?
• #11 by damac on 24 Dec, 2011 17:29
• 1.  Is it possible at all that the pin  was just in a position that allowed a tiny bit of fuel through and its ok during normal operation?  If not than I guess its obvious that pin isn't sealing, but everything was changed with bosch parts, I was there, so that definately sucks.  And we are lucky on our pump, there are just screws so I could pull the top off again and reseal. 
  
  2.  I have been working alone with the car and got an extra set of hands to help me today and I think I found a major problem and would love it if somebody could confirm these symptoms before I try and get it back on the road tomorrow
  
  The fuel appeared to stay primed but at its worst I couldn't seem to detect the fuel pumping.  I would let the car rest a couple hours between each session to get started and it would start up then slowly get worse until 5 minutes later the car would die on not hot restart right away.  EAch time I had been feeding from gravity to get things going again.
  
  I have been so concerned with the idle and not revving the hell out of it, just stabbing to see if it would return.
  
  My brother just helped me and something interesting happened.  We saw the same thing happen with a jug of fuel on the inlet with a filter.  Started up cold, idle started to lope, revs high with white smoke and within 5 minutes car would die when stabbing the throttle and letting off.  Car didn't want to hotstart so I would pop the hose and gravity feed again.
  
  Well I stayed in the engine bay and once he got it started each time he wanted to rev the hell out of it to see if it cleared out.  He kept it barely running high up but then as a few minutes went by the return line had foam/bubbles fighting each other on the car and the soft clear line started to fill up like a baloon and touched the firewall!
  
  I yelled to stop and by the time he did the inlet of the pump with the filter on it popped free and shot diesel across the driveway!
  
  I was not seeing this extreme pressure/bubbles when I messing with it alone but everytime it died and wouldn't hot restart I could swear I couldn't note a change in the fuel movement.
  
  Gas tank has been open when screwing around.  Over 6 months ago I treated the tank and put on another fuel filter and cleaned all tank connections and the sender/pickup screen(just a hint of sludge).  I also ran new lines back to the tank with soft unions in engine bay and near tank to see what was going on.
  
  Does this mean I have a bad return line restriction?  When initially starting up cold it seems like the fuel shifted and pickup through the stock setup lines and filter seemed fine.
  
  If so I have no idea why this is showing itself after my very simple pump adjustment but I guess crazier things have happened?
  
  Thanks for any info!
• #12 by burn_your_money on 24 Dec, 2011 19:56
• Most definitely sounds like an issue with the return. I'm surprised the injector soft lines didn't blow off.
  
  I'm pretty sure there is a check valve on the return side, that could be clogged up with junk.
• #13 by damac on 25 Dec, 2011 14:18
• I pulled the water seperator and I had the wierdest leak with the vehicle off where the stock lines went through the chasis so I replaced everything.  I just inspected all my unions and things appear sound from the outside, no fuel pooling.
  
  I did not put check valves back in the lines because I thought I would just introduce another potential problem.
  
  I went out to blow the lines just now with the cap off and blowing through the return it seemed like it took right away, smoky air coming from the tank.
  
  I went to blow the input line back and all it does is expand my hose until I can't hold it and the fuel then runs right back up to the end of the hose?  That doesn't seem right does it?  I could start to suck with the my mouth but of course can't keep that up.  So since the system is open perhaps it starts ok then goes downhill fast.
  
  Does that make sense if the in line is restricted that it would cause the out pressure in the return line, then shoot back to the input side like I mentioned?
  
  I see whats happening I am going to go open the tank again and pull the sender(it was clean), and then yank the whole input rail off the car and see what the heck is going on piece by piece and I imagine something will reveal itself here?
• #14 by burn_your_money on 25 Dec, 2011 17:31
• Quote from: damac on 25 Dec, 2011 14:18

  Does that make sense if the in line is restricted that it would cause the out pressure in the return line, then shoot back to the input side like I mentioned?
  

  
  Nope.
  
  Did you try blowing out the return with the fuel cap on? It should be vented and just let the air out. If it's not, that could be a part of the problem.