Diesel AAZ Intermentent Fuel / Idle Problems

[Orbitald]

I have a diesel AAZ Syncro and I'm having interment fuel problems. The 068 injection pump I have is off a 1.6L Jetta.

Sometimes it has trouble starting and other times not. After its started it seems to run fine except when I come to a stop and its at idle. Then it often starts to die unless I press the gas peddle which revives it. If it dies it takes a fair number of cranks before it will start again.

I thought it might be a clogged fuel filter but I changed it and its still happening.

Note that my van often sits for a couple of weeks at a time between use.

Any suggestions on what to check?

Thanks,

David R.
_________________
'87 Syncro Westfakia, 1.9TD ADE (AAZish), 068 Injection Pump, K03 turbo, 2.5" exhaust, Mercedes nozzles, SAAB Blackstone charge-cooler w/ 800cfm fan, Micro-1000 EGT sensor pre-turbo, boost at about 13psi, 235/70/16 with stock gearing

[ZanaEvyPapa]

sounds like air in the fuel lines. Have you verified there are no leaks? Also I suggest this for fuel lines: http://www.youtube.com/watch?v=SPFg1kyp68c
_________________
82 Diesel Westy
03 Jetta TDI
Gainesville, FL

[MarkWard]

What if it is not moving? I am not familiar with the syncro diesel tank, but maybe the fuel is sloshing away for the outlet under braking? There should still be enough fuel in the filter to run the engine, so my guess is way out there.

The AAZ should only have one lead that actually keeps the engine running. Above the fuel lines where they attach to the pump is a electric solenoid fuel cut off switch. Looks like an oil pressure switch. As a test, remove that wire and tape the end so it does not short out. Then add a second wire between the switch and battery power. For this test don't count on the electical system. Maybe run the wire from the B+ terminal of the alternator to the switch.

Now start the van and drive it. If the van stays running, you have an electrical problem that will need to be diagnosed. Also, you really need a clear fuel line between the filter and the pump for diagnosing problems. Good luck.

Edit, the van won't shutoff with the solenoid hot wired. You will need to remove your wire to shut the engine down if you can't stall it out.

[Orbitald]

Thanks for the suggestions.

I drove it today and it started having the same problem. I pulled out the choke and the idle didn't drop nearly as much and the engine never died.

ZanaEvyPapa: I do want to get that clear fuel line ASAP. I'm not sure how the choke might influence the affects of air in the line.

rsxsr: I'm pretty sure its not a fuel tank delivery problem as it has been running fine for quite a while with the same setup but still a good question.

I will definitely check the fuel cutoff lead and see if it might be intermittent as you suggest. That certainly could be a problem.

Thanks to you both for your great suggestions.
_________________
'87 Syncro Westfakia, 1.9TD ADE (AAZish), 068 Injection Pump, K03 turbo, 2.5" exhaust, Mercedes nozzles, SAAB Blackstone charge-cooler w/ 800cfm fan, Micro-1000 EGT sensor pre-turbo, boost at about 13psi, 235/70/16 with stock gearing

[Jeff's Old Volks Home]

Is the lower crank pulley moving around and throwing the pump timing off? VERY IMPORTANT... Usually what you see in the fuel lines in vacuum bubbles, not air. As the lift pump draws fuel from the tank the stream of fuel breaks and you see what appears to be air. This is normal. By pulling out your cold start you're advancing the pump timing by .23-.35 of a mm, masking the improperly timed pump... I've seen too many of these come apart not to be an alarmist about this. Check it. Check it today.
Sorry, Jeff
PS I sure hope I'm wrong.

[crazyvwvanman]

Like Jeff said, I would be very much concerned that the timing gear is shifting on the end of the crankshaft. This is a common failure on AAZ engines. You should STOP driving the van until you have pulled the timing gear from the end of the crank and closely inspected the parts!!!!!!!! REALLY!!!

Mark

[Orbitald]

Yikes! I'll check it soon!
_________________
'87 Syncro Westfakia, 1.9TD ADE (AAZish), 068 Injection Pump, K03 turbo, 2.5" exhaust, Mercedes nozzles, SAAB Blackstone charge-cooler w/ 800cfm fan, Micro-1000 EGT sensor pre-turbo, boost at about 13psi, 235/70/16 with stock gearing

[Orbitald]

One more question. Do you know of an online resource for this procedure? Do I need to actually pull my timing sprocket off and look at the back or is there something simpler I can do like measure the play with a gauge of some sort.
_________________
'87 Syncro Westfakia, 1.9TD ADE (AAZish), 068 Injection Pump, K03 turbo, 2.5" exhaust, Mercedes nozzles, SAAB Blackstone charge-cooler w/ 800cfm fan, Micro-1000 EGT sensor pre-turbo, boost at about 13psi, 235/70/16 with stock gearing

[?Waldo?]

There should not be any play to the timing sprocket. Best check is to pull the gear. You'll need a way to hold the crank from turning. I have a bar that I bolt to the sprocket and rotate until it hits the ground. You'll also need a new bolt for installing the gear as the bolts are single use.

[Jeff's Old Volks Home]

I have an idea, fly me out to California, away from the -20c and yucky weather, I'll bring tools and parts and for free, I'll fix your van, convert it to a TDi crank, time your pump. You need to feed me too...
Blessings, Jeff

[Witless Joe]

[Orbitald]

He,y thanks you guys!

I'm remembering now that I took the timing sprocket off in Feb of 2011 (at the suggestion of crazyvwvanman - thanks!) because I installed a different / used injection pump. At the time the gear and crank looked brand new.

That was less than 10K miles ago. Do you imagine it might have gone south so quickly? The whole engine only has about 16K miles on it.

Also, I ordered clear fuel tubing and will install it when it gets here. Witless Joe suggested checking for bubbles. Does the appearance of bubbles mean bad news, or good?

Last, does anybody know the part number of the once use bolt that I need to get?
_________________
'87 Syncro Westfakia, 1.9TD ADE (AAZish), 068 Injection Pump, K03 turbo, 2.5" exhaust, Mercedes nozzles, SAAB Blackstone charge-cooler w/ 800cfm fan, Micro-1000 EGT sensor pre-turbo, boost at about 13psi, 235/70/16 with stock gearing

[Jeff's Old Volks Home]

It can happen in a hurry. The bolt part # is N 905 771 01 and the TDi crank pulley part # is 028 105 263 D.
Did you check your pump/belt timing yet?
Jeff

[MarkWard]

In the clear line, these are actually "space" bubbles. They can be a result of a restriction in the fuel supply, like a partially clogged filter etc, causing a vacumn and the result is these bubbles. You could also have an air leak in the supply system to the pump and have actual air bubbles. These are external to the pump and fairly easy to solve. If you have clear "space" bubble free fuel supply, that is ideal.

From reading above, I have no experience with this particular engine, but it looks like you need to replace the crank bolt when you have the sprocket off. When you had yours off did you replace the bolt? I recall some time ago a member was advertising the crank upgrade, fix. I remember them being in Arizona, but I could be wrong.

[?Waldo?]

Yes, I can update the crank for the TDI sprocket with the engine/crank in situ. I've had quite a few people come to my place in Flagstaff to have it done. I no longer 'advertise' it, tho, as I plenty of work. If the van made it to Flagstaff i could do that easily enough.

[Orbitald]

I pulled my crank timing sprocket off and found a D shaped mating so I guess that's good news. Sorry Jeff, I was so looking forward to your visit.

And I also found some crud on the tensioning pulley which I cleaned off.

Tomorrow I'm getting a new serpentine belt, installing the clear fuel tubing, and getting it timed correctly.
_________________
'87 Syncro Westfakia, 1.9TD ADE (AAZish), 068 Injection Pump, K03 turbo, 2.5" exhaust, Mercedes nozzles, SAAB Blackstone charge-cooler w/ 800cfm fan, Micro-1000 EGT sensor pre-turbo, boost at about 13psi, 235/70/16 with stock gearing

[crazyvwvanman]

I forgot, you don't have an actual AAZ. You have one of the 1.9TD VW Industrial Motors that were being passed off as AAZ for a while. Those were still made years later than the true AAZ vehicle engines. Looking at VW parts data for the Industrial engines that TDI style pulley was fitted to the 1.9TD Industrial Motor beginning around 1999.

Mark

[Jeff's Old Volks Home]

Please tell me you did measure your pump timing before you went through this exercise...
Jeff

[Orbitald]

Question:

In searching around about the AAZ crank nose key way problem I've seen some discussion about installing a clutched alternator pulley.

Is this something I should do?

In the past I have noted my setup looking exactly like this video with a pulsing in the serpentine belt tensioner:
http://youtu.be/PdrREAVNNcQ

As opposed to this video with the free-wheel alternator pulley:
http://youtu.be/S2vvVPd9YCk

And I've found mention of a few different pulley part numbers:

- 028 903 119 AA

- 028 903 119D

- 022 903 119C

Last, is this method of tapping for an end bolt the best way to install these pulleys?
http://www.vwdiesel.net/forum/index.php?topic=15010.0

Thanks!
_________________
'87 Syncro Westfakia, 1.9TD ADE (AAZish), 068 Injection Pump, K03 turbo, 2.5" exhaust, Mercedes nozzles, SAAB Blackstone charge-cooler w/ 800cfm fan, Micro-1000 EGT sensor pre-turbo, boost at about 13psi, 235/70/16 with stock gearing

[MarkWard]

My ratchet style pulley failed before the alternator did. Seems the speculation is that this setup "saves" the crank sprocket attachment. I would think the valve train, ac compressor and power steering pump would put more "loads" on the crank compared to the alternator. Looking a the link, seems easy enough to adapt. I am more interested in what is smeared to the timing belt tensioner. What material is it and where is it coming from?