First time diagnosing low power / 1x/limp

kiva822

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'03 Wagon, '03 Golf
Greetings

***NOTE: For those that don't like long-winded, detailed posts, skip to the numbered questions below** but, for context...

OK, the sedan is being quirky and I'm taking my first shot at diagnosing the low power issue. First, background:

A few months ago, the only symptom I was having was, occasionally, if I really got on it in 1st gear (e.g. did not roll into the throttle @ 1800rpm or so, just went WOT), it would sputter, go nowhere, and spew a huge cloud of black smoke. I would then let off the pedal and it would go along it's merry way. This happened maybe 4-6x. I was pretty good about rolling into the throttle instead of stomping on it.

Then, in the last 2 or 3 weeks, it's happening more often + the car seems underpowered. It is especially bad when it hits about 140 degrees on it's way up to 190 (e.g. that zone where it's ok, to start driving it normally, but isn't fully warmed up yet). I'm noticing a general lack of 'pull' and, when going WOT in 2nd-4th, it will even rev up and then start pulling a bit more after 3500rpm. Just really inconsistent power and never full power, as I can tell. It went into limp mode 1x, but I can't replicate it, even on a hill.

Unplugged the MAF and it runs somewhat better, but the problem doesn't resolve itself completely. With the tune, the MAF unplugged defaults to, I think, 1275 (see logs).

Right now, my hand is pretty banged up from racquetball, so getting deep into it will have to wait a week or two and I can update the thread then. However, for now..

(1) when unplugging the MAF, an *improvement* in power is indicative of a MAF problem, or, if the MAF is the issue, unplugging it should resolve it altogether? With the MAF unplugged, it still sputtered, just not as bad.

(2) the vacuum hose from the N75 to the actuator is the cloth braided type. Other hoses have been replaced, it appears. Should that one be replaced as well, as a matter of course? Do most replace the actuator hose with a high temp silicone rather than the cloth braided?

that's it for now. After getting the MAF question answered, I'll move on to the hoses and then testing the actuator and N75 (per the diagnostic thread).

Here are the logs i've taken. If anybody wants to see any different blocks, etc., let me know. It's my first time posting logs, so let me know if I do something wrong:

MAF plugged in:

http://pics.tdiclub.com/data/500/LOG-01-003-011-004.pdf

MAF unplugged:

http://pics.tdiclub.com/data/500/2LOG-01-003-011-004.pdf

any tips on to properly read these things would be great....

Sorry for the long post..I tend to be thorough...

matt
 

jcrews

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The turbo output looks good. It's a larger unit, ie VNT17, right?
The MAF output looks good (close to maximum -1275).

A default of 1275 mg/H means your tune has MAF delete.
A spec MAF = 850 mg/H means you have an EGR delete. You probably knew both of those things already.

*** The IP looks good, but could use a little more advance in the basic setting. What's it set to now?

Check the group 007 readouts when stone cold and when warm. What's the IAT and fuel temperature readout? Include these values in a log. There is plenty of requested advance, so the values should be OK.

The bogging could be caused by a sticking advance piston. I don't see any egregiously late delivery in the log. With the MAF plugged in, output looks good.

***I can't tell what your requested IQ is. Replace group 004 with 001 and make a recording. Check the IP inlet for air ingestion if you have poor output despite good indications.
 

kiva822

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Location
Chico, CA
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'03 Wagon, '03 Golf
jcrews, thanks for the feedback. In order to list the specifics of my vehicles in my sig, I had to delete my disclaimer, which explained how much of a idiot i am ;)

So, I didn't know that a "MAF delete" was the reason it defaulted to 1275. I knew that was part of the tune as a default when you unplugged the MAF.

I didn't not know that 850 = EGR delete. I know I don't have an EGR, but didn't know that 850 number indicated so.

I will check the 007 readings as well as do a new log w/ group 001.

I'll have to look up the basic setting IP advance, as I don't totally understand how to look at that / read it. I'll get back to you.

A wrinkle: when I got this car, it had just had a pump swap done by a trusted mechanic in Sacramento. However, they left it with retarded timing (below the bottom line, but on the screen). I adjusted it to right on the middle line. Now, when I checked it the other day, it's at 33, about 1/2 way between the middle and lower line.

When I cracked the cover to adjust the timing, I saw the dreaded paint marks for a mark and prey. I called the previous owner who assured me those were there when he bought the car and did a dieselgeek tb right after purchase (I have the receipt for that TB kit). Sooo....part of me still wants to confirm mechanical timing, but need a camshaft lock tool to do so, as I understand.

So, perhaps first re-adjust the pump timing mechanically to between the middle and top line? Then move on to the other items?

matt
 

NewTdi

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Matt, for $3000 I will take your car off your hands and later will tell you what is wrong with it! :eek:
I hope you get to the bottom of this.
 

jcrews

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You will need a cam setting plate to confirm the cam timing.

However, you can check the tensioner: Push on the belt with your thumb. The indicator on the tensioner (about 4 or 5 o' clock as you look at it) should displace. When you remove your thumb, the indicator should return to the adjusted position (indicator bump is opposite the notch). The belt should have good resistance, and should not be loose immediately after you relieve the pressure.

You can also increase your confidence by setting #1 to TDC at the flywheel mark, and seeing if you can get a drill bit in the lock pin hole (or at least confirm you can see the hole in a mirror).

I've replaced timing belts on 3 engines with previous paint marks, and I didn't attempt to remove them. I just put a note of it in the maintenance record.

Your basic timing setting should be at about 60-65 @ 140 (just use the graph) in order to reach the tuned advance points. I can't think of a good reason for drift right now other than IP sprocket slippage (3 bolts not tight enough - 25 N-m is standard). Drifting towards advanced over a long time normally indicates nozzle wear due to opening early.
 

kiva822

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'03 Wagon, '03 Golf
ok, so some confirmation (thanks for patience)

re: confirm timing: remove valve cover, look for "v' on #1, TDC should be at flywheel mark, then try and get bit in hole at IP. Correct? Or are you speaking of something where I don't remove the valve cover, just find TDC via flywheel mark and look for IP hole?

basic timing = "TDI timing" in VCDS, adjusted by rotating the IP, correct? Love those mini, mini, mini adjustments :)

thanks again for your time
 

jcrews

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You can leave the valve cover on, because the IP hole won't be aligned (around 1 o' clock as you look straight at the sprocket) if the cam is in the wrong position. This will only increase your confidence a little because there's only a weak connection between the cam/crank timing due to the adjustable sprocket. It may not be worth the effort at all.

Basic timing settings refers to using the TDI timing graph.
 

kiva822

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well, just went to set timing, and now it's at 21 @ 162. WTH? Appears to be some drift...adjusting now...
 

jcrews

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It should never drift in that direction, so that's bothersome. Let me know if any bolts felt loose, and if any are single use (not gold, with a narrow "neck" near the head).
 

kiva822

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ok, none of the bolts were loose. These appear to have some blue-ness to them and, interestingly enough, there is a bit of blue 'paint' or something on the IP sprocket. I kind of remember that last time I was in here, but can't be 100% sure.

bolt:



IP bolts / sprocket (am I saying that right, 'sprocket'?):. Bolt missing is the one I took out for pic; yellow paint marks are the ones I referred to:



In a thread a while back about adjusting the IP timing, I thought these bolts were OK. Are they single use and I didn't know it? If so, WTH are they doing in there? Ugh.

re: the tensioner test...i'll have to dig into that one a bit more. I can't seem to move this belt by pressing the top more than 1/4 inch, if that..

matt
 

jcrews

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That bolt doesn't appear to be single use, although the new style is typically gold colored.

The blue paint is a little weird.

The toothed belt won't have much give, which is good, just make sure the tensioner moves and springs back.
 

kiva822

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ok, so, for now, I will check the tensioner, re-tighten the IP bolts and see what kind of timing I get. I'll also go ahead and get some new bolts. I have an 11mm IP to install and, heck, maybe i'll be looking at a TB job at the same time...though there is supposed to only be 20k on this belt/tensioner, etc.

any ideas on drift that direction? Would a failing IP do that?
 

jcrews

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Other than slippage, possibly invalid basic settings caused by an intermittently stuck advance piston (which would explain bogging/stalling).
 

All of Us

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Jesse and Matt:

Do you suppose someone put locktite on the IP sprocket bolts? That color looks suspiciously like the non-permanent (low strength?) type blue locktite.

Dan
 

NewTdi

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Locktite blue is usually a few shades darker .. could be that Matt used a flash to take the picture and that is a whole lot of Locktite ...
 

jcrews

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Taking the Sherwin-Williams slogan literally, perhaps? :D

It looks like maybe someone tried to mark the head locations as is called for when working on the LCAs. Other than that, maybe someone wanted to add some flair to a dull engine :)
 

kiva822

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ok...timing set 137 @ 60-62. Man, I forgot the fun of that one...

I know that the LCA's were updated with TT stuff as well as new tie rod ends, ball joints, etc. I don't understand why you'd have to do that to do suspension, but I guess I'll cross that bridge of understanding at a future date..

Other than slippage, possibly invalid basic settings caused by an intermittently stuck advance piston (which would explain bogging/stalling)
I don't understand this...can you explain? Is that related to the IP?

Also, method of checking air ingestion at IP other than bubbles in fuel line?

Off to do some more logging w/ block 1, 3, 11,

BTW, at temp, block 7: Fuel = 61.2, IA 55.8 (ambient about 66 F), Coolant 90.9.

matt
 

kiva822

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ok, did some 1st through second and a long 3rd and 4th, followed by some more 1st through 2nd.

When i left the driveway temp was just above the white area of the dumb gauge. Got on it in 1st and car sputtered hard, but at the upper RPM's. Kept doing runs, etc. and by the end, sputter was very faint and it was more of a 'flat spot' in the 2500-3500rpm range or so. Overall, ran way better with the timing where it's at now, which one would expect, given how retarded it was.

so, what would cause the sputter and/or flat spot? why is it better when it is warmed up? Your statement about the advance piston sounds intriguing...i'll do some searches on that term.

Also, when i got done with logging, checked timing at it was 143 @ 59-62. I let it idle for cool down while I typed this and I just checked it again: 158 @ 59.

Just closed VCDS and opened it again and got 153 @ 59

Just closed and opened it again at got 155 @ 59

For giggles one more time: 156 @ 58

Ok, I give...what's up with the different readings and why not at 140-ish where I set it before?

Log:

http://pics.tdiclub.com/data/500/LOG-01-001-003-011.pdf
 
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jcrews

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Log 004 again as well.

The advance piston is in the IP, and pressure to it is modulated by N108 "cold start valve". If the piston sticks in its bore, the ECM should store a timing control deviation code, and logs will indicate the actual start of injection does not closely follow the request. Basic settings may seem to be all over the place as the piston sticks at different positions in the bore. This condition can be caused by dirty/bad fuel, poor filtration, or equipment defects/failure/aging.
 

Farfromovin

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I forget from my ALH days but I think the pump timing (basic) should be a little more solid than that? If you have an 11mm to put on there, I'd do that before worrying about the internals of your 10mm of course!
 

jcrews

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If you post the .csv renamed to .xls I can make a few plots to try to explain a flat spot, but not sputtering.

The first value is fuel temperature, and won't be 140. It's a 1 byte unscaled value in channel 000, and will change with the fuel temperature (converted in deg. C in channel 007). That's why the electronic graph makes it easy to set the timing, since the timing is dialed back as the temperature increases (the idea is that hotter fuel has a shorter ignition delay).
 

kiva822

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hmmm....well, i'm betting failing IP. It came from the golf that nick bought at the same time I bought the jetta. Unknown IP history but with about 140k, i think. Oh well.

11mm is on the way. Should I run Diesel Purge through this one?

Sounds like another log of groups 003, 011 and 004 during that warm up period, maybe make a 'marker' when it sputters?

Also, of note, even when I went into limp, I was unable to retrieve any codes / none where there. I only drove it about 7 miles before I was able to scan it. It has yet to throw a code during this whole thing.
 
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jcrews

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True limp mode involves codes and default values.

An open vacuum line will create limp mode symptoms but not necessarily a code if it's short lived enough.

Please do mark when you get a sputter.
 

kiva822

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True limp mode involves codes and default values.
An open vacuum line will create limp mode symptoms but not necessarily a code if it's short lived enough.
Please do mark when you get a sputter.
man, that's weird then. Last Thursday, took off w/ engine warm but not totally warm, power totally cut, had black smoke (possibly white too, but I was trying to pull over). Cycled key on/off and it came back to life. Perhaps just an open vacuum line.

I did just see that the vacuum line at the EGR delete is terminated with a screw. Hmm. I will look at all the vacuum lines and terminate properly. they were replaced 25k miles ago. Should I also replace the actuator line (braided one)?

I will do some more logs tomorrow and do markers. My wife can help me..she's helpful that way :)

My hand is totally sore now from all the finagling, so a little break will be good. I really appreciate the help and will post back as soon as I get another log. I should also check the actuator movement and to see if holds vacuum, right? Then, proceed through the low power thread diagnostics (e.g. n75 issues).

It would make sense that the piston would stick less when everything is warmed up, no?

Thanks for the tip on the first number in the timing. So, by weird drifting, you mean the 2nd number, correct? E.g. drifting from say 60 down to 35 again?

matt
 

jcrews

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Yes, the timing number (60,35, etc) shouldn't move around.

From the last log, the turbo response is normal, no sticking or leaking is evident. Fuel injection is maxed out, so all indications point to smooth and consistent maximum output.

If you can catch the engine in the act with 001,004,011, we can cobble together a solid diagnosis.
 

kiva822

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As an FYI, that first run in the last log had a pretty good sputter, but I wasn't logging block 4, so I suppose that doesn't help us.

I almost edited out my stupid post above re: fuel temp influence on the timing..but i'll leave it so some other noob can learn from my ignorance. Thanks for pointing it out in such a non-mocking manner...

Jesse, thanks so much. Would never own a TDI without this forum and people like you to turn to..

oh, and Andrew...I should come down to the bay and we can swap cars for the weekend...that would be fun. ;)
 

kiva822

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ok, did some more logging tonite.

.xls version:

http://pics.tdiclub.com/showphoto.php?photo=74518&title=4-6-11log-01-003-004-011&cat=500

let me know if posting the PDF is needed.

You will notice that markers 2, 3, and 7 are missing. I deleted them as they were mistakes. Also, most of the other markers are still accurate and reflecting a little blip, but might not be. The first couple were definitely blips.

I have no idea how to read logs, but I notice that the "actual start" in group 004 spikes (correct term?) right where I made the first couple of marks / noticed a sputter or flat spot.

FYI, it never did a hard-core sputter on me. I think it likes the timing advance.

Also, some facts I remembered to note (which may or may not be related):

(1) Car gets about 13-15% less FE than the wagon w/ same size wheels and same driving. I know, a million things can impact FE, but thought I'd post that.

(2) IMO, the car *sometimes* gives me a mild stumble / miss at idle. It's barely noticeable, but it's there...not all the time, though. I tried to get it to do it for Matt-98AHU @ the GTG, but it wouldn't.

thoughts?
 
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