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Compression
Posted by: wayne v (19491) on 2014-04-11 19:02:40 In Reply to: Update - compression seems good posted by mclaire on 2014-04-11 18:49:21	Share \| Report

The car I did a compression check on yesterday was about 150 across the board but that was a 1.8 t, anyone have specs for the 4.2??

Thread:

One sick S8 - mclaire 2014-04-10 21:40:03 (511 views)
- You mention a bad alternator and jumping it at least once, so had you jumped it before..... - BLT4SPD 2014-04-12 09:28:25 (276 views)
  - That makes sense - mclaire 2014-04-12 10:06:48 (204 views)
    - no. next after the coils are POS units N122 and N193, then ECU. - quattro.pilot 2014-04-12 12:33:34 (215 views)
      - This is an '01 with a 40 valve. I thought only 32 valve prefacelift cars had POS's? - mclaire 2014-04-12 19:58:55 (181 views)
        
        sorry, my bad.. reading comprehension fail. very likely you're correct - quattro.pilot 2014-04-13 00:26:26 (173 views)
- nearly 200k out of the alt is pretty stellar - sorry yer havin probs but least it's home and yer not - pkrasusky 2014-04-11 21:26:27 (231 views)
  - Yep, your 100K ownership was a solid test :) - mclaire 2014-04-11 21:50:00 (220 views)
    - ferget on the plugs, it was prob 1/2 way thru me ownership? - pkrasusky 2014-04-11 22:55:36 (217 views)
- Update - compression seems good - mclaire 2014-04-11 18:49:21 (224 views)
  - Compression - wayne v 2014-04-11 19:02:40 (215 views)
    - The 4.2 should be higher 150-160. - TozoM8 2014-04-11 20:18:41 (196 views)
      - By "seems good" all I meant was  -  mclaire  2014-04-11 21:24:03 (217 views)
        
        120psi is really low, for reference i was around 160psi at 290k miles...   -  audinutt  2014-04-12 10:53:23 (179 views)
        
        You may be right, especially if compression holds and does not quickly leak out. At your mileage...  -  TwoSeven  2014-04-11 21:35:11 (216 views)
  - On battery alone, even a good one, you'll have trouble. If you want to test stuff with the... - TwoSeven 2014-04-11 19:00:28 (205 views)
- Honestly sounds like textbook alternator failure to me. I'd swap in a known good one and go... - TwoSeven 2014-04-11 08:09:10 (237 views)
  - sorry, the code was P0012 - mclaire 2014-04-11 08:53:07 (239 views)
    - Well that does change things. I'd still replace the known faulty alternator - but check the TB... - TwoSeven 2014-04-11 08:58:27 (222 views)
      - Exact same symptoms when my alternator crapped out  -  Phil C  2014-04-11 09:19:26 (253 views)
        
        OK, I'll disconnect the alternator  -  mclaire  2014-04-11 09:32:28 (228 views)
        
        There's a reason electric cars have batteries the size of sensible people's gas tanks.  -  TwoSeven  2014-04-11 11:01:32 (225 views)
- rent a compression tester. (this would be my first thing to check) - audinutt 2014-04-11 01:08:42 (205 views)
- Those codes could be ancient... - BrianC72gt 2014-04-11 00:55:02 (238 views)
  - not ancient - mclaire 2014-04-11 09:12:14 (218 views)
  - I'll bet your valves are probably fine... - BrianC72gt 2014-04-11 02:11:05 (222 views)
    - I agree that bad timing would not have "fixed itself" - mclaire 2014-04-11 09:15:39 (236 views)
      - not far-fetched at all  -  BrianC72gt  2014-04-11 13:40:53 (215 views)
        
        Second it  -  wayne v  2014-04-11 18:58:31 (212 views)
        
        Until 2 days ago I ran the car occasionally with a non-charging alternator  -  mclaire  2014-04-11 21:33:23 (237 views)
        
        Internal voltage regulator failure can sap juice rather than create; that is worse than not working.   -  TwoSeven  2014-04-12 21:28:00 (234 views)

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