AAZ engine hard to start. Timing? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• AAZ engine hard to start. Timing? by haybayian on 17 Jun, 2009 02:17
• Hello Group. Everything seems to be OK. I redid the IP timing, fuel pump working, etc and yet the thing takes a very long agonizing cranking before firing.  Should I fiddle with the IP 3 bolt mount? If so should I pull the pump away from the block or vice versa? Sorry to be so crudely ignorant.
  
  Haybayian
• #1 by Zulfiqar on 17 Jun, 2009 02:21
• seems as if your pump is draining off fuel, you have an airleak somewhere in the return system, the little rubber overflow pipes are a once only install and seal just once, or the return fitting is letting in air to drain off fuel from the pump
• #2 by haybayian on 17 Jun, 2009 13:15
• Quote from: Zulfiqar on 17 Jun, 2009 02:21

  seems as if your pump is draining off fuel, you have an airleak somewhere in the return system, the little rubber overflow pipes are a once only install and seal just once, or the return fitting is letting in air to drain off fuel from the pump
  

  
  Thanks,
  Could you explain. How would a faulty return fuel line (letting air in) could interfere with the starting of this engine?
  Haybayian.
• #3 by Golf/Jetta on 19 Jun, 2009 02:51
• is it when the engine is cold? if so the glowplugs, compression, air getting in the IP
  
  if its happening when hot, air getting in the IP.
  
  

  Quote from: haybayian on 17 Jun, 2009 13:15

  Quote from: Zulfiqar on 17 Jun, 2009 02:21

  seems as if your pump is draining off fuel, you have an airleak somewhere in the return system, the little rubber overflow pipes are a once only install and seal just once, or the return fitting is letting in air to drain off fuel from the pump
  

  
  Thanks,
  Could you explain. How would a faulty return fuel line (letting air in) could interfere with the starting of this engine?
  Haybayian.
  

  
  is it leaking anywhere?
  if air is getting in the pump then the one way check valve could be faulty
  the IN fuel line is under vacuum from the pump
  a working IP, pumps about 12 psi inside, if not more (30 psi)
  but a faulty return line should leak it.
  an IN line to the pump would let in air if there a leak..
  lets say the bonjo bolt, copper O-ring "IN port", on the pump is leaking
  then air has a way of getting in the pump, but should only effect after it cranked over. unless alot of air got in. oneway check vavle (FUEL GOING BACK TO THE TANK)
  to prove this, you could rig something up to throw fuel at it and see if it leaks somewhere. air pressure test (no more then 12 psi) and see if it holds it.
  another one could be a seperate fuel source.
  try blowing back to the tank on the IN fuel line, if it goes back then check valve.
  if all check out OK then i would have to say compression or glowplug system when cold
  
  how is your compression?
  glowplugs work?
  is your anitfreeze staying put?
• #4 by haybayian on 19 Jun, 2009 05:47
• Quote from: Golf/Jetta on 19 Jun, 2009 02:51

  is it when the engine is cold? if so the glowplugs, compression, air getting in the IP
  
  if its happening when hot, air getting in the IP.
  
  Thanks again,
  My problem seems to be cold start indeed. I am therefore going to make my glow plugs functional.
  Haybayian