AAZ, low power, low boost, doesn't rev, otherwise perfect - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• AAZ, low power, low boost, doesn't rev, otherwise perfect by TITan on 21 Oct, 2015 08:42
• Bit of a backstory:
  The engine: AAZ with Garrett T2 turbo, boost controller set to ~1.1 bar/16 psi, governor mod, modded boost pin, 2.5" downpipe. 1.0mm timing
  
  The car ran perfectly for about half a year (still a bit lower on power compared to my old SB 1.6 TD @ 1.2 bar, but the lowdown torque was better) then the IP sprung a leak from the distributor head. Didn't have time to fix it right away so the leak got worse and worse. At the same time the max boost started falling to factory levels (0.75 bar). Than to top it off the cooling system started acting strange (dead thermo switch plus the thermostat started sticking)
  
  Flushed the coolant, changed the switch and thermostat - no more overheating. Changed the oring - installed the pump head 180 deg out, took a bit of time to figure that out . No more leaking IP  But also no more power  The engine struggled to rev past 3500 RPM (in the begining it puled strongly to 5000), boost was down at 0.5 bar.
  
  Things I have tried since:
  Changed the fuel filter - no change
  Checked the turbo by hand - no excessive play. It's already spinning at idle. 
  Swapped in the pump from my old SB 1.6TD - changed the characteristics of the engine, but not much better.
  Since I have a different flywheel I checked the timing marks by dropping a valve. They were a bit off, but not by much. Rechecked the timing on both pumps atleast three times.
  Removed the rest of the (quite restrictive) exhaust. - a bit better, but not much change.
  Cleaned/tried removing the cone air filter - different sound, not much change of performance.
  Removed the line to my wastegate so it doesn't open - still almost no boost.
  Tried running the pump directly from a can of diesel and ATF to clean it out - no better
  Adjusted internal pressure - not much change.
  Played around with the pump settings - a bit better, but can't get it to run properly
  Cleaned the wastegate and rechecked that it was moving freely (it was stuck when i got the engine) - boost is a bit better, but not by much.
  Could always get a bit of black smoke.
  
  After fiddling around with the pump settings it pulls to about 4000 RPM and boosts to 0.7 bar/10 PSI withouth the wastegate.
  
  Other than that, the engine runs perfectly. The temperatures here are just above freezing right now and it starts up right away. No white smoke at all. From time to time a bit of blue smoke right at startup, but nothing drastic. Idles nicely, quite responsive lower down the rev range, max power is from 2000 to 2500 RPM right now.
  
  I really don't know what to try next. Lift pump maybe?
  
  Pic for attention:
  
• #1 by RunninWild on 21 Oct, 2015 20:11
• Compression? Injectors?
• #2 by TITan on 22 Oct, 2015 05:17
• Haven't tested either.
  But from how nicely it starts I'm guessing the compression is ok.
  Have to make a adapter for checking compression on a diesel and find somebody with/make my own pop-tester.
• #3 by theman53 on 22 Oct, 2015 07:00
• What exactly are you looking for?
• #4 by RabbitJockey on 22 Oct, 2015 07:17
• have you visually checked that the wastegate is working and not stuck open?
• #5 by dontdoemyourself on 22 Oct, 2015 19:47
• Are you 100% sure your cam to crank timing is perfect? The compression test could help rule that one out
• #6 by TITan on 02 Nov, 2015 04:06
• Quote from: RabbitJockey on 22 Oct, 2015 07:17

  have you visually checked that the wastegate is working and not stuck open?
  

  
  Wastegate is working, and is making a good seal. No cracks wisible on the pedal or turbo housing.
  
  

  Quote from: dontdoemyourself on 22 Oct, 2015 19:47

  Are you 100% sure your cam to crank timing is perfect? The compression test could help rule that one out
  

  
  Double checked that my flywheel marking was spot on TDC via dropping the valve and looking at when the nr 1 cylinder made contact in both directions, than used the center from that. Reset the timing 10 times probably.
  
  Compression test will be done as soon as possible. Same with poptesting the injectors (maybe trying some GTD injectors in the  meantime).
• #7 by air-cooled or diesel on 02 Nov, 2015 06:24
• Quote from: TITan on 21 Oct, 2015 08:42

  Flushed the coolant, changed the switch and thermostat - no more overheating. Changed the oring - installed the pump head 180 deg out, took a bit of time to figure that out . No more leaking IP  But also no more power  The engine struggled to rev past 3500 RPM (in the begining it puled strongly to 5000), boost was down at 0.5 bar.
  

  
  sounds like when you 'fixed' pump you now may have a air leak, or have reinstalled pump head wrong