Anyone interested in a problem solving exercise? AHU no start

So i feel a bit bummed out for a couple reasons.
1) that i haven't contributed anything to this forum and have only asked for help.
a) sorry, after i get this sorted, i'd love to help someone else accomplish a
similar goal.
2) that a motor swap, that should have been straight forward is not...


Ok. So with help, i solved my previous question. Thanks guys!


Now, brand new long block AHU in the westy. No start.
Heres what i've done:
- Checked timing 1308761490u times. every go is the same. Pin fits in pump, plate fits in camshaft, and flywheel mark lines up. Today i even went as far as dial gauging and Libbys vacuum trick to ensure #1 was TDC.
2- All air is out of IP. Used an outboard motor ball pump on the out flow side. Pulled fuel through the pump and had it squirt blah blah blah.
3- Checked Glow Plug circuit. Test Light OK for the plugs, in the 20sec, for the heating with coolant sensor unplugged.
4 - Moved IP throughout the range available for timing the pump. However i haven't yet got the gauge and measured plunger. As the pump was rebuilt, and on a strong working motor before, so i have no reason to believe its out.
5-changed batteries, Full charge each time.
6- Ran a Vag-com auto scan. First came with 6 faults. Cleared the codes, now i have none.
7- Ill post 2 pics and a video, let me know what you hear.


I'm kinda at a loss here, Anyone got any suggestions? Or lives locally that wouldn't mind taking a look with me?

Yes, since the pump was rebuilt, I'm thinking the QA is out. I'd hammer mod it and try again.

But this is after you verify 12v to the stop solenoid on the pump, AND that the QA is getting minimum voltage (Group 019 on VCDS).

Then check the crank position sensor and #3 injector as per Bentley.

Photos and video

Thanks Abacus. How come you think the QA would be out? Additionally, how do you hammermod a car that's not running?

I also checked, were getting 12v to the stop solenoid.

I'm not that savvy with VCDS as this is my first go with it. Hang in there with me, i'll wrap my head soon.

Heres what it sounds like:


https://youtu.be/C4Fg3BYgiU4

It should be cranking over much faster than that,what voltage on the battery?
and do I hear an air leak?

Too short for forums:

12.8v

did you correct those initial hard faults before clearing them ? n109, n108, and g80 will all cause a no start ...either ground or power, double and triple check your wiring against the diagrams, then check again

I agree with Jim, but saw this in the initial post:

freeturns said:

6- Ran a Vag-com auto scan. First came with 6 faults. Cleared the codes, now i have none.

Click to expand...

And 1.9Zook is correct, it should turn over much faster than that. Much faster.

I mentioned the quantity adjuster because whenever a pump is resealed/rebuilt it's nearly impossible to get the QA back in the correct slot. Even tightening down the QA bolts will wildly swing the IQ one way or the other.

cleared codes

Wouldn't the codes come back if i had cleared them, tried to start and scanned again ?

The one that jumps out at me is that N109. It's fairly easy to assess, and easy to fix, if you have a soldering gun.

freeturns said:

Too short for forums:

12.8v

Click to expand...

What is the voltage while cranking?

gets down to 8.8

freeturns said:

gets down to 8.8

Click to expand...

Start with a proper, new battery and charger it overnight first.

Ok Christmas update:

Had 2 half days, thanks family!!

- Traced some of the crappy wiring, found the blue t2 connector was for the generator. Repaired some chaffed crap in the wiring loom.
- re-primed the fuel system, bled injectors etc.
- timed the IP with the dial indicator, i was "close"
- checked the timing again. This time i decided to to the t-belt assuming the flywheel mark was off. Which it was!! Measured piston at the top, counted teeth clockwise and CCW /2 and boom, TDC. Fired up on the second try. Should have been the first, but i forgot to plug in the ECU.. doh.


Anyways, thanks for all the help you guys!

- Checked timing 1308761490u times. every go is the same. Pin fits in pump, plate fits in camshaft, and flywheel mark lines up. Today i even went as far as dial gauging and Libbys vacuum trick to ensure #1 was TDC.

Click to expand...

I guess you should have checked the timing 1308761490u + 1 time.

Mechanical timing off on an AHU/1Z strikes again.

So easy to have the pump off a tooth.

So, did you find that the flywheel mark somehow ended up not at TDC (verified by checking piston TDC)?

Abacus- Yeah, this was my first time timing a TDI... Got it! Sounds pretty good, i think. I think i got pretty lucky with the IP being in the range. When i fired up the vag com, it seemed to be a bit retarded but well within the spec.

Windex -

Exactly, the flywheel was replaced by a guy in ca, he neglected to mark the flywheel on the old motor. the "death bolt" sheared (crank pulley) at 65 and the van was parked after that ~ 2 years a go. Saved some money and a bought a long block and just assumed the "old" mark would be good.

Verified with a welding rod, measured at the top, then counted teeth cw and ccw till the drop. Divided by 2 and was the flywheel was off by 3!!!

Thanks again for all the help ya'll

It's just that most of us were going by what you posted, and you were adamant the timing was on. That's the first place to look on these models due to the ease in which the crank sprocket moves. By posting what you did, you told us emphatically that it was not the timing so not to bother mentioning it.

Had we known the history of the car we could have diagnosed it easier and more quickly.

But no matter, I'm glad it's sorted out now.

Absolutely no sarcasm, I do appreciate the diagnostic help, this is my first ahu. And the more I can learn from y’all the better!

You came to the right place, the people here have forgotten more about these cars than I'll ever know.

Abacus said:

You came to the right place, the people here have forgotten more about these cars than I'll ever know.

Click to expand...

Now, there's some modesty.