Analyzing wear on injector nozzles - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Analyzing wear on injector nozzles by overdrivegear on 02 Jun, 2007 11:03
• I think it might be time to replace my injectors with brand new ones.  The thing is that they work ok and the engine runs fine enough, but with 350k miles, it might be time for some new ones.  I haven't pulled them off yet, but my question is how will I be able to determine if my injectors need replacement? (the IP was just rebuilt).  I would think that after that length of usage, they more than likely need a change out.
• #1 by rallydiesel on 02 Jun, 2007 11:09
• You need to get them pressure tested. You can't tell just by looking at the nozzles. The person you does the pressure testing can then adjust them to open at the right pressure. Find a diesel specialty shop to get this done.
• #2 by Vincent Waldon on 02 Jun, 2007 11:55
• Mileage is also a good clue... 60K-100K is probably enough for a set of nozzles.... so if you're sure yours have 350K on them treat your engine to a new set... your pistons, mileage, and the environment will thank you.
  
  BTW, the nozzle part of the injector (the part that does all the work) can be removed and replaced all by itself... often significantly cheaper than replacing the entire injector, although you'll still want to have them tested for the correct breaking pressure.
• #3 by vegfuel on 02 Jun, 2007 16:53
• overdrivegear,
  
  I own an 81' VW diesel N/A such as yours. Is yours a 4 speed? If so, what is your top speed in 4th gear? And at how many rpm? Mine I think might need injectors rebuilt and pump timed. My little 4spd is screaming at 50 mph.
• #4 by 91 ECO on 03 Jun, 2007 19:08
• I was thinking the same thing when I recently had my injection pump rebuilt.  Bought a set of rebuilt injectors from a good source and installed.  The car developed a bad case of nailing so I took the old injectors to a local diesel shop.  Even after 300K miles, they still had a good spray pattern and would break at the correct pressure.  Put the old injectors back in and my problem was solved.  Find a diesel shop and ask them to test the injectors.  If they check out ok, reinstall with new heat shields.  Just my .02.
• #5 by burn_your_money on 03 Jun, 2007 21:15
• Quote from: "vegfuel"

  
  I own an 81' VW diesel N/A such as yours. Is yours a 4 speed? If so, what is your top speed in 4th gear? And at how many rpm? Mine I think might need injectors rebuilt and pump timed. My little 4spd is screaming at 50 mph.

  
  
  I had a 4 speed rabbit, I could cruise at 60 and the engine was happy, top speed was about 70-75 but the car had other issues
  
  Check your transmission code, I had a tall tranny 4A. www.scirocco.org/gears