So I finally got my AAZ's rebuilt and pop tested by Kelch Injector Service. They came recommended by a VW guy who works on the AAZ motors. I had the nozzles replaced with 265's and set to 150 bar.

I just got done installing them along with new heat shields. It starts, and runs great expect that I have nailing in what apears to be 4 out of the five.

No Nailing, as far as i could tell on old injectors

All the lines are tight, no fuel leaking.

I rechecked the timing. Set at 28 BTDC

Compression is good in all cylinders 400 or greater

I am getting ready to take it for a good hard spin on the interstate and see if that helps.

Is there anything I am missing?\

Thanks

Scott

Injection should be quieter with the 2-stage injectors but increasing the pop to 150 and advancing the timing to 28 pretty much cancels that out.

It may be that you have one odd sounding cylinder instead of 4.

Thanks for the help.

So if I back the timing off, I should expect to hear some reduction in the nailing?

Is there any long term issues with the injectors causing the nailing, I am assuming the nailing is still be caused by a small amount of pre-ignition.

I have no smoking or decrease in performance, so all in all I am pleased with the upgrade.

Scott

(10-11-2009 07:07 PM)ForcedInduction Wrote:  Injection should be quieter with the 2-stage injectors but increasing the pop to 150 and advancing the timing to 28 pretty much cancels that out.

It may be that you have one odd sounding cylinder instead of 4.

Quote:So if I back the timing off, I should expect to hear some reduction in the nailing?

Yes. 28* is a little advanced, both mine are set at 26*.

Did you use new nozzles? If you did, you might give them a few days to wear in.

Sounds good.

They are new nozzles, so I'll give it a few days, if not i' look at the timing.

I thought you were running 28 when you had them, so Ill back it off a bit and see what happens.

Thanks

(10-11-2009 08:58 PM)ForcedInduction Wrote:  

Quote:So if I back the timing off, I should expect to hear some reduction in the nailing?

Yes. 28* is a little advanced, both mine are set at 26*.

Did you use new nozzles? If you did, you might give them a few days to wear in.

Well- It is still running good, but deffinitly got some nailing going on in #1 and #5. The other three cylinders sound good.

I swapped the #1 and #2, the nailing stayed with #1 so the injectors are good. I did use new Heat Shields.


I noticed a small leak, drip coming from the #1 DV, so i'll pick up a new washer for it tomorrow.

I have not ID anything particular about #5 to explain the Nailing. I will try swapping it out tomorrow.

I tried to do a Diesel Purge, but NAPA was out, I used SeaFoam, with no noticeable effect.

I may still turn the timing down a bit.

Any other ideas

Thanks

Scott

Then you're in the same boat as me with my #5 still nailing after changing the pump and injectors. My next move is going to be pulling the prechamber and swapping in my good spare.

I have been trying to avoid the P-word. I am not sure what i am looking for when I inspect them.

Tonights research on the FSM is pre-chamber's and DV's

(10-12-2009 07:40 PM)ForcedInduction Wrote:  Then you're in the same boat as me with my #5 still nailing after changing the pump and injectors. My next move is going to be pulling the prechamber and swapping in my good spare.

Well new washers on the #1 Delivery Valve stopped the fuel leak, but the nailing is still present.

I set the timing back to 24* it seems to run a bit rougher now.

Stuff I am thinking may be related and options to fix problem.

1. Ignore it as long as it runs good and get better gas mileage ( 29+)

2. Replace #1 DV. I noticed a small amount of pitting on the side of the collar. I am not sure how this was caused or its effect.

3. Adjust Idle. Idle is currently around 600 rpm. Stock should be up around 800rpm ( right?)

4. Adjust Relief Valve Spring. The car does have 315,xxx miles.

5. Return Lines. Is there a wrong way to hook them up, as long as the cap is on #5 and the line runs from #1 to filter?

6. New Hand pump. Mine leaks when you use it, old plastic type, but no leakage when sealed up.

7. Do a true diesel purge, maybe run some bioside through the tank to be sure.

8. Adjust timing chain stretch. I have the offset key and new tensioner spring in my tool box.

9. Play with injection timing some more, maybe 26*

10. Replace AAZ with old cleaned up injectors, see if nailing follows.

11. Send AAZ's back to be retested.

12. Inspect Pre-chambers- still not sure exactly what i am looking for.


Thats my list any input?

(10-20-2009 07:59 PM)dartrpm Wrote:  3. Adjust Idle. Idle is currently around 600 rpm. Stock should be up around 800rpm ( right?)

Yes, 750 +/-50

Quote:4. Adjust Relief Valve Spring. The car does have 315,xxx miles.

Worth doing even without nailing.

Quote:5. Return Lines. Is there a wrong way to hook them up, as long as the cap is on #5 and the line runs from #1 to filter?

Its all a common flow. You could plug the ends of 1&5 and have the return flow from the middle if you wanted.

Quote:6. New Hand pump. Mine leaks when you use it, old plastic type, but no leakage when sealed up.

If it leaks fuel out, it can leak air in.

Quote:7. Do a true diesel purge, maybe run some bioside through the tank to be sure.

DP is a waste of money. Find someplace that sells B50-B100 and run a tank of it before the weather gets cold. 16gallons of that will clean the entire fuel system far better than 16oz of lantern oil will clean the injection pump. Keep a few extra filters with you.

If it weren't going to be so cold this week, I'd go down to Shoco oil and do the same myself.

Quote:8. Adjust timing chain stretch. I have the offset key and new tensioner spring in my tool box.

Like the relief valve, this is something good to do no matter what.

Quote:9. Play with injection timing some more, maybe 26*

24* may be too retarded with 150 bar pop pressure.

Quote:10. Replace AAZ with old cleaned up injectors, see if nailing follows.
11. Send AAZ's back to be retested.

You already swapped injectors and the sound stayed put, it shouldn't be an issue with injection.

Quote:12. Inspect Pre-chambers- still not sure exactly what i am looking for.

Ball condition, melting, cracks, plugged nozzles, carbon buildup, etc.

You'll also be able to get a decent look at the piston top and cylinder walls if you rotate it to BDC.

Well I got to some of the list this weekend.

Very little progress in decreasing roughness at idle or nailing.

On a positive it still runs solid and is getting better fuel mileage (28+)

(10-20-2009 07:59 PM)dartrpm Wrote:  3. Adjust Idle. Idle is currently around 600 rpm. Stock should be up around 800rpm ( right?)

Adjusted idle to around 700, and adjusted Rack Dampener. Dampener may need to be replaced, it is the gold unit, but its when all the way in with no change in idle quality. Tomorrow I will back it all the way out and try adjusting it again.

4. Adjust Relief Valve Spring. The car does have 315,xxx miles.

Pulled spring it was less than 20mm. I stretched it out to 28 and reinstalled. Has anyone rechecked how long stretching the spring lasts
?

6. New Hand pump. Mine leaks when you use it, old plastic type, but no leakage when sealed up. This is my most likely culprit. There is a lot of air bubbles in the fuel line coming to the fuel filter and returning from the relief valve. New one is on the mail.

7. Do a true diesel purge, maybe run some bioside through the tank to be sure.
Tank of B100 goes in tomorrow

8. Adjust timing chain stretch. I have the offset key and new tensioner spring in my tool box.

9. Play with injection timing some more, maybe 26*
Timing set to 26*

12. Inspect Pre-chambers- still not sure exactly what i am looking for.
On the list for tomorrow



Thats my list any input?

The only way a diesel can suffer pre-ignition is if the fuel is injected before the cylinder is hot enough to burn it.
Back off the injection timing a lot and see if it improves. If it does then advance it slowly until you start to get knocking again, repeat until you've found the sweet spot.

(10-26-2009 12:49 AM)Kiwibacon Wrote:  The only way a diesel can suffer pre-ignition is if the fuel is injected before the cylinder is hot enough to burn it.
Back off the injection timing a lot and see if it improves. If it does then advance it slowly until you start to get knocking again, repeat until you've found the sweet spot.

I am trying to chase two problems at once. I am trying to eliminate all the variable by ensuring that I fix all the little issues, making it easier to ID the final issue. I want to be sure the idle quality is poor or the fuel economy is down because of air bubble or fuel leaks before i get crazy with adjusting the timing.

I did replace the primer pump last night, with some increase in smoothness and idle quality. I have a fuel problem of some sort. The primary filter is completely drained when I accelerate the engine. You can see the fuel sucked out of the bowl and the air bubble forming.

I have ID this as one of the issues and I think I have a crack somewhere that only becomes evident when the engine is warm. The idle quality and smoothness of the engine diminishes once the engine is up to full operating temperature.

This weekend I am replacing all the plastic hard lines and cleaning the tank strainer.

Any other ideas?

(10-28-2009 09:45 PM)dartrpm Wrote:  Any other ideas?

Pressurise the system.
I've had leaks before which let air in but didn't even leak enough diesel to appear wet.
Pressurising the system showed me instantly where it was, of course it took me four hours to fix the electric pusher pump so I could do that.

This weekend was productive, but I lost some ground on Monday

Over the weekend, I adjusted the Valve's. I had adjusted them less than a month ago, but I must have been on crack that day because they were all super tight. I don't know if i used the wrong gauges or what, but the exhaust was at about .10 mm instead of .35mm all the way across. That was step one.

At the same time I installed the new Woodruff key. I had 9* of stretch when I checked it a month ago. All is back to spec with the new key.

Additionally I replaced the hard plastic lines from the lift pump to the filter and from the filter to the IP.

This resulted in reasonable smooth idle and a much better running car.
That was until yesterday afternoon. My 50 mile drive into work was smooth, car ran great, on the way home, I stopped of in town and suddenly the rough Idle was back and the idle speed increased by about 100 rpm.

I checked the idle adjust and it was still tights, I couldn't adjust in down enough to make any difference in the idle speed. I removed the throttle rod to ensure there was no binding causing the issue.

This morning the car was acting better but not as good as it was over the weekend.

The only variables I haven't eliminated yet are that I need a new air filter, mine is oil soaked from a malfunctioning oil separator and I am running straight water in my coolant. I replaced the thermostat and will be adding a tank heater this weekend, so I used some over the counter rad flush and am running it and water till I add the tank heater. temps are a little above 80, but not bad.

Any input?

Thanks

Well I am still chasing the nailing. I believe I have eliminated any fuel issue, short of rebuilding the lift pump.

Today I checked the compression as I reamed and replaced the glow plugs.

All cylinders had over 400 psi. Not bad I guess for just turning 320,xxx.

I pulled the #1 Injector to inspect the pre-chamber. Look's good, far as I can tell. The atomizer ball is present and intact. There appeared to be more oil on the glow plugs than I would have expected.

Is good compression with lots of blow by a sign of head issues..ie valves and or guides?

This nailing and not smooth idle are bugging the crap out of me.

On the to do list are new motor mounts, lift pump rebuild and new air filter setup. The new air filter setup is a copy of Forced's with a home built oil separator.

The only other issue at hand is fuel economy is down from an average of 27-28 to 25-26. The fuel station I use say they don't winter blend, ( I live in Washington State) but fuel economy is down anyways. So I don;t know if this is a fuel issue or a engine issue.

I am about to take it to the Shop and suffer through the $100 hour rate to solve the issue.

Any ideas

Thanks

Scott

Two questions:
Firstly, does your fuel tank pull a vacuum? If so this will be making any air leak much worse after a short amount of running. Get out and vent the tank if it does pull a vacuum and see if that helps.
Secondly, if it's not an air issue, have you tried retarding the timing?

(12-28-2009 07:49 PM)Kiwibacon Wrote:  Two questions:
Firstly, does your fuel tank pull a vacuum? If so this will be making any air leak much worse after a short amount of running. Get out and vent the tank if it does pull a vacuum and see if that helps.
Secondly, if it's not an air issue, have you tried retarding the timing?

Well I backed the timing off to 24 today. I think my timing may have been off last time i did it. I am not sure how much effect having the vaccume shut off valve still hooked up to vacuum would cause. I am assuming its not good.
The nailing is gone now. I may try adjusting up a few degrees and see what happens.

Though the nailing is gone, the engine still feels like it is running rough, almost like it has a miss. The Rack Dampener has no effect on the idle quality at all. I have tried it all the way in to all the way out.
I am sure there is no air in the fuel. I installed clear fuel lines all the way around and can visualize no air.

I don't notice a vacuum in the fuel tank when it is low or any other time. The only time i noticed anything was when i was draining the tank. The fuel obviously came out faster with the cap off than with it on. I may pull the vent and clean it anyways.

I installed the new air cleaner set up. It is the GMC tube air filter attached to a 3" ABC 90* and an heavy rubber adapter, with a catch can style oil separator plumbed into it. The car is a bit louder with it installed. I am sure some of it is from the hood insulation falling away from the hood and the rest from the old aircleaner insulating the sound some what.

I also have a fair amount of blow by. If I got good compression, and blow by, would that make one think valve stems and seals or would it be normal for a 320,xxx mile car.


What else could I be checking.

Thanks

Scott

Bump- Hoping for some input. Ive still got a rough Idle and what seems to be a PCV / blowby issue. I have had random occurrence of oil coming up through the breather drain and the dipstick popping off. I have enough blowby that the hood has dark streaks on it.

The compression is good, over 400 psi on each cylinder. What else could I be checking or doing?

thanks

Scott

Check that the valvecover's internal oil separator isn't clogged. A previous owner might have stuffed something in there thinking it would remove more oil.

Well I took apart the entire PCV system today. I cleaned everything real well and made a few adjustments. There was some gaps in the oil splash guard on the valve cover. I added some more sealant to the cracks. I pulled apart the oil separator in the air cleaner and cleaned and resealed it. The air cleaner stud was broken, so i drilled and tapped it for a new bolt.

In addition i checked the valves, a couple were a little tight, but nothing significant.

I attempted to check the fuel pressure by t-ing into the pressure side after the filter. Unfortunenatly my pressure gauge only went to 10 psi. I guess Ill pay more attention at harbor freight next time.

The issue is once I got it all back together, I cant get it to start now. I have run the hand pump till all the air is out of the lines.
It turns over fast and tries to start when I give it a little Starting fluid. I disconnected the vacuum shut off to be sure nothing was wrong there.
I cracked #1 injector line and had fuel coming out of it when i pumped the hand pump. I clamped the fuel return line to ensure it wasn't free flowing. I have clear fuel lines so I can see there is no major air bubbles in the lines. The only change I made was putting a longer hose on the secondary filter side, moving the filter more level with the pump. Would this have any effect?

Any help or ideas

Thanks

Scott

(01-22-2010 07:57 AM)ForcedInduction Wrote:  Check that the valvecover's internal oil separator isn't clogged. A previous owner might have stuffed something in there thinking it would remove more oil.

It may take some long cranking to get it started 1-2 min solid