New injectors + compression test results - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• New injectors + compression test results by wolfsburged on 29 Nov, 2009 16:08
• 1984 Jetta 1.6TD, unknown "180k+" miles. I'd been driving the car a decent bit up until the beginning of November when I had to travel all month for work. I was noticing that my mileage was around 38mpg on average, with one 41mpg tank driving very conservatively. Also I have somewhat hard/rough starts in the morning when it is (for around here!) cold, roughly upper 30s to low 40s F. Starts better with a double hit on the glow plugs. Glow plugs and relay are new. I also am getting murky brown coolant despite a number of flushes through the system.
  
  I got a rebuilt set of injectors from Giles and swapped them in today along with testing out my new compression tester.
  
  I noticed that the two injectors closest to the timing belt had a ton of carbon built up both on the injector and in and around the heatshield. So much so that I could not remove the old heatshields & reused them after cleaning up in there. The two injectors on the opposite side had little/no carbon buildup and were very wet.
  
  
  (these are backwards - furthest right injector came out closest to timing belt)
  
  
  Carbon build up
  
  
  No carbon build up
  
  
  Oooh shiney!
  
  
  New injectors are the cleanest thing on this thing!
  
  So anyway, my compression readings are:
  Cyl 1: 360 PSI
  Cyl 2: 400 PSI
  Cyl 3: 360 PSI
  Cyl 4: 380 PSI
  
  According to the Bentley these are basically at or below spec, but seem at least to not have a ton of variation, so I'm thinking I'm at least marginally ok. I'm now suspect of my oil/water cooler unit and will be replacing/resealing it when I do the heater core job.
  
  Any input on realistic compression limits and/or the carbon buildup on my old injectors?
• #1 by rabbitman on 29 Nov, 2009 16:17
• I wouldn't think of reusing those heatshields: http://www.vwdiesel.net/forum/index.php?topic=22292.0
  
  One way of getting 'em out is to pull the injectors and crank the engine over using the starter, they should blow out, if that don't work try a slide hammer or large screw screwed into the hole in the shield. I can't remember what it looks like on the other side of the heatshield so I don't know how easy it would be to bugger the head by stickin' stuff in there.
• #2 by Vincent Waldon on 29 Nov, 2009 17:06
• Quote from: libbybapa on 29 Nov, 2009 16:18

  Then pull it out with a large screw screwed into the center.
  

  
  This is the key trick... a big wood screw works well so that the threads seat into the hole well.
  
  You may mangle the heatshield a bit but it will come out. 
• #3 by burn_your_money on 29 Nov, 2009 18:21
• I like using a long tapered punch. Lightly hammer it in there and then just wiggle it around. That will usually break it loose.
  
  Your compression is comparable to my old engine. If oil consumption is low I would highly recommend synthetic oil for the winter. It will really assist with starting. Like Andrew said, if everything else is in order you should be ok.