First time diagnosing low power / 1x/limp

[jcrews]

Based on the conditions leading up to and following a deviation, it looks like the N108 advance solenoid is occasionally sticking. The advance mechanism itself looks OK, because the log indicates the mechanism is seeing the wrong pressure rather than getting jammed for a moment.

Mark 1: want 10.3 deg, got 1.1 CSV 35% @ 4053 : black smoke/ power drop expected

Mark 4/5/6: got 28 deg! (want 9.5-11) @ 2800: Power loss/ increased noise expected

Mark 8: a few degrees late in a couple of spots, but not as bad as above. May not be noticable.

Mark 9: 8 degrees late, similar to 1.

Mark 10: 3-5 degrees late, not as bad.

11/12: Nothing interesting

I'd like to see the N108 if you remove this injection pump.

 

[kiva822]

Hi Jesse

Thanks so much for the detailed analysis. That's really helpful. For somebody like me, what is the best way to be able to learn to read those logs / interpret myself? I am starting to wonder if I should just leave it up to the experts and learn more basic stuff.

Ok, so it appears diagnosis is the IP and/or N108 and no amount of diesel purge, etc. is going to 'fix' it? I see that there is a thread for replacing the n108. However, since i have an 11mm in the mail to me, the best course of action is to swap pumps and see how it goes?

 

[jcrews]

The N108 is hiding under the rear IP bracket, so the pump has to come out to service that part. You mentioned bad fuel somewhere, so you could have corrosion or contaminants remaining in the pump. Can you give me some more information about that?

As far as reading the logs goes, you'll notice a few measuring groups include both "specified" and "actual" values (ex: 003, 011, 004). The values should be close to each other. Interpreting deviations can be easy (enough to set limp mode), or may require some thinking in the case of momentary and/or intermittent problems. The best way to learn is to look through the measuring blocks, gather some baseline knowledge, and take a look at some recordings. There's not much to it once you get accustomed to the data format and the control functions.

 

[kiva822]

The N108 is hiding under the rear IP bracket, so the pump has to come out to service that part. You mentioned bad fuel somewhere, so you could have corrosion or contaminants remaining in the pump. Can you give me some more information about that?
.

I mentioned bad fuel in another thread, i believe. However, that was in the wagon.

The IP on the car now has a history unknown to me. It's only on there because previous owner wanted to keep his 11mm and I wasn't knowledgeable enough to know to go out and get a replacement instead of taking the one off an unknown car.

Lesson learned: never allow parts on the car without a verifiable history on said parts.

Personally, I buy my diesel at Chevron (I've cheated and got Safeway a couple of time and I know they buy wholesale from a variety of suppliers). I run PS about every other fill.

 

[kiva822]

for those w/ the N108 issue that may read this in the future:

IP removal procedure:

http://65.110.12.166/showthread.php?t=284004

Advance Solenoid R&I procedure:

http://pics.tdiclub.com/data/517/Advance_Solenoid_Replacement_Procedure.pdf

for me, I'll be just swapping the IP, but I may still replace the AS. We'll see.

 

[kiva822]

ok, reviving old thread.....

11mm ip is on there. Car runs better, overall. Been tweaking the tune a bit.

However, when between 140-175 degrees or so, when you go to get on it, it still sputters and blows black smoke. tuner tried taking a little fuel out at lower RPM, but still does it (less smokey overall, though.)

Took a log:

http://pics.tdiclub.com/showphoto.php?photo=78016&title=log-01-003-004-0111&cat=500

in that log, marker #2 was a big sputter and blow of black smoke.

Now, i'm starting to wonder if I have a vacuum problem somewhere or if the original 10mm IP was even bad at all. I don't see the same block 4 issues the were in the previous logs though....

opinions? How does that log look to you guys?

Also, FYI, I've noticed some wonkiness with the temp gauge wandering. Scan-gauge temp readings have been solid / unchanging. Did throw a CTS code briefly. Ordered one up and will replace it. Any chance that's related to the sputtering and, overall, not so good MPG?

matt