ALH CEL questions

[pkhoury]

Recently got my ALH working, thanks to the help of Brian (alphaseinor). He finished the timing belt on my ALH, and I'm hoping next go around, I'll be able to do it myself.

Anyways, some codes that come up:

-------------------------------------------------------------------------------
Address 01: Engine Labels: 038-906-012-AGR.clb
Part No: 038 906 012 GN
Component: 1,9l R4 EDC G000AG 4308
Coding: 00001
Shop #: WSC 00066
VCID: 62CBC135EED7AC5FD1-4AE8
3VWSP69M83M065092 VWZ7Z0B4934946

6 Faults Found:
19561 - Valve for Intake Manifold Flap (N239)
P3105 - 35-10 - Open or Short to Ground - Intermittent
17056 - Cylinder 2 Glow Plug Circuit (Q11)
P0672 - 35-10 - Electrical Fault - Intermittent
17057 - Cylinder 3 Glow Plug Circuit (Q12)
P0673 - 35-10 - Electrical Fault - Intermittent
17058 - Cylinder 4 Glow Plug Circuit (Q13)
P0674 - 35-10 - Electrical Fault - Intermittent
16618 - Boost Pressure Regulation
P0234 - 35-10 - Limit Exceeded (Overboost Condition) - Intermittent
16785 - EGR System
P0401 - 35-10 - Insufficient Flow - Intermittent
Readiness: 1 5 0 0 0

I get a CEL, so I don't know if it's for the EGR, boost pressure, or intake manifold flap.

Also, I'm presuming that 3 of 4 glow plugs are bad, given these errors? Everyone says IDParts is a good bet for glow plugs, but does anyone else have any 2 cents on that? And I'm presuming I can install them with a 10mm semi deep socket on a 1/4" torque wrench? I have a Span-On 1/4" torque wrench just for the super precision jobs.

I'm told that the boost pressure can be a vacuum problem or N75 issue. Being my first ALH, I've read what the N75 looks like, but I have no clue what it does.

Final question - if resistance checks out okay, is there any reason not to pick up used glow plugs from the junkyard? I actually got lucky and picked up an ALH long block and other goodies for $99 during a wheelbarrow sale... and learned that even the block by itself is HEAVY lifting it into the back of the JSW by myself (I actually had to lift that block 5 times that day!).

 

[WildChild80]

Used glow plugs could work but you roll the dice every time you take them out, if you break one off you've got fun times ahead...and any money you saved will evaporate instantly.

ID parts is stellar, I've used them many times and they will do you right.

When I did an EGR delete, I pulled the flapper solenoid and it threw a code, plugged it up and let it dangle and all is well, try setting your EGR to 33768 and see if the codes stay away. As for the over boost, look for a vacuum leak and check the vacuum actuator and see when it starts to move and when it stops... assuming it's not crusted up inside and make sure it holds vacuum. Also check your EGR valve for the vacuum leak as well as verify your vacuum pump is pulling 25 inches or so, the nipple at the pump is prone to leaking, there's a fix for that too...



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[BobnOH]

Since they're all intermittent, it's hard to say which one is triggering the light. Proly all or any.
The GP errors could be bad plugs, but could be the harness. Further testing will reveal.
The other 3 have various causes, use the Ross Tech wiki for troubleshooting.
Does it run? Maybe ask Brian to have a gander?

 

[csstevej]

I know I can vouch for IDPARTS....they are great.
I would personally clear all codes and see what comes back.
If resistance is good on GP , maybe your not getting current to the GP’s and it’s the harness.

 

[BobnOH]

Oh yea, you asked about kind-

Bosch and Beru are both OEM. I wouldn't use anything else.

And avoid ebay, amazon, alibabba, prothe, unless you know their source.
VW TDI Search Engine

 

[Votblindub]

How's that glowplug harness doing? I had codes like that on my white car. I replaced one plug at a time. Swapped em around and there was no rhyme or reason to how it threw codes, just threw codes. It disappeared once, but when I rolled 2 car lengths it came back. It all went away after I swapped the harness. It might not be your case, but just check it.

 

[vandermic07]

I suspect a vacuum leak for EGR and Boost codes

 

[pkhoury]

An update. I did take a gamble and changed out my glowplugs with junkyard specials. Of 8 plugs pulled, 6 tested good, but I only qualified 5 as good. One of them had a partially broken tip (but they plug looked fairly new). The other 5 measured between 6 and 10 ohnms.

Oh - the glow plugs. All that I removed were Bosch, and all that I put in were Bosch. For a "cheap" part like a glowplug, I know better than to use Chinesium. Despite my cost saving efforts, I really try to stay from all Chinesium crap parts!

My cylinder 1 plug measured about 200-300k ohms, but it worked. The rest were in the megaohm range, and yes, some had slightly swollen tips, so there was a lot of patience pulling them out. I sadly didn't have any anti-seize around (misplaced it from last weekend), but I hand threaded the replacements back in, and then torqued to 132 inch pounds (which is 11 ft lbs, which is supposed to be the torque spec on these). No more glow plug errors according to VCDS.

I still get an overboost error, but no more CEL. The car feels like it has slightly more power, but that 01M makes it feel rather lethargic at best!

Almost forgot to add - the PO had some funky T-nipple where the vacuum line comes off the pump into the brake booster. I replaced that with factory hose (from the junkyard), and the original vacuum line that went to the EGR valve was tied in a knot. I simply used a T and factory hose, but had it circle to itself, rather than have an open end somewhere.

I did pick up 2 of the vacuum valves, of which I believe one is the N75? I measured all 4 at the terminals, and got 15.6 ohms. So resistance for a relay/solenoid is good. I guess the question now is if the other internals are a-okay?

One more edit - Brian suggested the turbo vanes. I have yet to learn about turbo vanes. Thankfully, I do have a spare ALH turbo laying around (from the same junkyard's wheel barrow sale in the past), as well as a clean intake, so it's tempting to get a squeeky clean intake (as best as possible on an ALH, anyways), and then check the spare turbo, which doesn't really have a lot of play, given how old it is. Ha, there was one turbo on an ALH at the junkyard - talk about a hotdog down a hall way! Makes me wonder if it was a runaway turbo before that car was retired!

On a final note, I'm finding that the junkyard is a great place for figuring out how this stuff works by taking things apart (like engines and heads, transmissions, etc).

 

[WildChild80]

Yes it is... sometimes I experiment on junk yard cars myself

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[P2B]

The other 5 measured between 6 and 10 ohnms.

Your meter is probably bad - good glow plugs measure between 0.8 and 1.2 ohms.

 

[pkhoury]

Your meter is probably bad - good glow plugs measure between 0.8 and 1.2 ohms.

Haha, oops. Thanks for the correction. 0.6-1 ohm. Decimal point error! Either way, the car starts up perfectly now and I don't get any more glow plug errors. And the meter better not be bad. It's a Fluke that's made here in the US, and it's served me well for the past 13 years.

 

[wonneber]

Your meter is probably bad - good glow plugs measure between 0.8 and 1.2 ohms.

That's why I prefer an amperage test for higher current devices, not resistance.

Resistance is good for fuses, switches & such.

 

[pkhoury]

Understood. At least they work for now, anyways. I just need to check VCDS again and see if the other codes are still popping up. After replacing some vacuum hoses and the new glow plugs, the car definitely feels like it has a bit more power. The whole car itself is a constant work in progress, though, including the bubblying purple tint on the rear window that needs to get scrapped with a razor.