AAZ Gone Wrong

[WeekendMechanic]

So I was driving very slowly and all of a sudden the engine started to vibrate violently,I managed to make it home with very little power and white smoke.
As soon as I arrived I checked the timing and it was perfect.I checked the injectors they all seem good too.I just ordered a compression tester to see if somethings wrong with the cylinder head valve train,that still has to arrive.
This pump is a late model AAZ pump where the timing is done from the 19mm bolt I did unscrew the 19mm pump bolt by mistake when doing timing but re tightened it, maybe I
over torqued?
It works perfectly for a second or two then vibrates violently again.Iv been having this intermittent minor quirk that`s been happening since the timing belt change 2 weeks ago, of the revving a little higher upon startup more than usual... a little but noticeable.
Is there a way to test the pump?
I need to be certain its the pump before I take it to a shop to fix.
Before all this its been running straight for 3 years.
Iv been searching here and on google but cant find an answer.

Notes :  # Timing is perfect (checked with gauge) at 0.82
 
                      # Pump  has 100,000 miles
           
                     # Checked to see if cam sprocket started to rip itself to pieces, its not, I installed a clutch pulley years ago to prevent this as well.

                     #Starts instantly as always, works perfectly fine  for 2 seconds  then goes bizerk as if its running on 1 or 2 pistons.

                     

                     
 
                     
               

[fatmobile]

 Clear fuel lines to and from the pump?

[WeekendMechanic]

Clear fuel lines to and from the pump?

Yes, clear blue diesel.
I took off the return pipe and there is slow flow on idle.

[Giles@PerformanceDiesel]

Since you have said this problem has only happened since you did the timing belt I would suspect it's got to do with that.

Do you know what the timing was set to before you did it? Even if you loosened the front nut on the hub it won't affect the timing as the hub is taper fit and you would need to pull it off with a puller.

Did you have the camshaft locked when you pinned the pump hub? Was the camshaft sprocket loose when you did the tensioning?

Try resetting all the timing and drive it again, try .95mm on the pump sprocket as I feel this is much better. 

I had this engine in my Passat for over 100,000 miles running over 20 psi on the K14 and I had a problem like you described but only on initial cold start-up and only if I gave a lot of throttle. Then it would misfire terribly and smoke like crazy for about 2 minutes.  Sometimes it would stall but would restart ok.

I never managed to find out what was the problem.  Being that I can swap in different pumps and injectors I know it wasn't any of those, came to the conclusion it was something to do with Turbo Stall maybe?
   
Giles

[WeekendMechanic]

since you have said this problem has only happened since you did the timing belt i would suspect it's got to do with that.  do you know what the timing was set to before you did it? even if you loosened the front nut on the hub it won't affect the timing as the hub is taper fit and would need you to pull it off with a puller.  did you have the camshaft locked when you pinned the pump hub? was the camshaft sprocket loose when you did the tensioning?  try resetting all the timing and drive it again, try .95mm on the pump sprocket as i feel this is much better.  I had this engine in my Passat for over 100,000 miles running over 20psi on the K14psi and i had a problem like you described but only on initial cold start up and only if i gave allot of throttle then it would missfire terribly and smoke like crazy for about 2 minutes.  Sometimes it would stall but would restart ok, i never managed to find out what was the problem.  Being that i can swap in different pumps and injectors i know it wasn't any of those, came to conclusion it was something to do with Turbo Stall maybe?   
Giles

Hi
Thank you for sharing...

I've changed 2 timing belts on this golf, the previous I got dead on .80mm last is .82mm.

My immediate thought was the timing too, as it is too much of a coincidence, but I have cranked it over 3 times, cam line is centered and is spot on .82mm on every TDC mark.

Is there even a way to check turbo and pump, or is this something that can only be done with expensive equipment?

I've ordered a new set of nozzles and will be lapping the insides, so I can eliminate injectors.

[rabbid79]

Sounds like a weird misfire.  I'd try loosening each injector line (at the injector) in turn to see if the problem gets worse.  If you loosen a line and it gets worse, then you know that injector isn't contributing to the problem.  If you loosen a line and nothing changes, then at least you know what cylinder the misfire is happening on.  Make sure you wear gloves and put a clean rag around the line to keep fuel from going everywhere.

[WeekendMechanic]

I got the compression tester and diagnosed it further.
It arrived today, I`m getting between 400-470 psi on 2,3 and 4 cylinders but as little as 5psi on cylinder 1.
I would like to know what happened, when I was doing the timing belt I did have the cams line off-center for a moment, whilst turning the crank by hand I did feel a valve at one point, but I did not put that much force onto it. do you think I loosened something up because of this and it came off later is this possible?
Any advice on the next procedure do I have to take off the head I've never touched a head before? 

[ORCoaster]

Before you go hog wild pulling off the head take some time to measure the clearance on the exhaust and intake valves on the #1 cylinder. 

Then pull the camshaft and see if you cracked a valve by removing the cam followers and pull up on the valve stems.  I think if they are broken at the shaft you would have them coming up with the springs. The keepers hold the valve shaft against the spring pressure. 

If you cracked a valve the yeah, you have a head to pull.  Not a big deal just work getting it off the exhaust and intake manifold if you choose to do so.  Not everyone does that but then they have a lift whereas I do not.  Hard to wiggle that much weight when leaning over the engine that far.  Seems to be a setup for popping the small of your back right out. 

OK, so I am a wimp. 

Oh for future reference:  Once you feel that tap of the piston to the valve STOP and back up the wrench.  Bending a valve may have been the failure here. 

[WeekendMechanic]

How would I go about measuring the valve clearance of the intake and exhaust and why would I need to?
I remember this symptom being intermittent it happened once 2 days after the timing belt change for about 2 minutes then went back to normal for some 12 or so days until it was permanent,  I don`t hear any metal when cranking the key and why only 5 psi what does this all indicate?

[ORCoaster]

5 PSI in a cylinder on a VW engine indicates you have a problem.  But you already know that.  Something is not sealing well.  Normally the rings get worn and compressed air goes past the poor seal between the cylinder wall and the piston.

In your case, there is a huge loss going on somewhere.  Like a hole in the piston or valves that are not sealing.  I suggested checking the valve clearances as a way of getting at a valve problem.  The cams are designed to push down on a small wafer of metal, a shim, of a given thickness, and still have some amount of clearance between the cam and the metal shim.  I was thinking that if the valve is not seated on the head then the spring would be able to push up more on the cam follower and thus reduce the clearance.  Maybe my logic is messed up.  But if you dropped a valve it may have beat a hole in the top of the piston and that is the real problem.

How to check valve clearances.  Read the Bentley you should own for this type of work.  We on this forum can't possibly be directing you for every major repair.  You might find it on the past messages or U Tube but honestly, IF you OWN this car and intend to take care of it get the proper repair manual or you will cost yourself both time and money.  Yes, I understand they are about 50 bucks but there is NO BETTER investment you can make for your money. 

[WeekendMechanic]

5 PSI in a cylinder on a VW engine indicates you have a problem.  But you already know that.  Something is not sealing well.  Normally the rings get worn and compressed air goes past the poor seal between the cylinder wall and the piston.

In your case, there is a huge loss going on somewhere.  Like a hole in the piston or valves that are not sealing.  I suggested checking the valve clearances as a way of getting at a valve problem.  The cams are designed to push down on a small wafer of metal, a shim, of a given thickness, and still have some amount of clearance between the cam and the metal shim.  I was thinking that if the valve is not seated on the head then the spring would be able to push up more on the cam follower and thus reduce the clearance.  Maybe my logic is messed up.  But if you dropped a valve it may have beat a hole in the top of the piston and that is the real problem.

How to check valve clearances.  Read the Bentley you should own for this type of work.  We on this forum can't possibly be directing you for every major repair.  You might find it on the past messages or U Tube but honestly, IF you OWN this car and intend to take care of it get the proper repair manual or you will cost yourself both time and money.  Yes, I understand they are about 50 bucks but there is NO BETTER investment you can make for your money.

I don't understand why you're posting if you're not going to be helpful please refrain from further input as nothing your giving is helping this situation.

Would anyone with a calm mind and heart intervene?

I've taken the camshaft off and nothing looks out of place.

[ORCoaster]

Sorry you find my information offensive.  Just using my calm best I can.  Your only next step is the big pull of the head.  Post some pics they may give insight as to the problem unless it is a gaping hole that is like DUH? obvious. 

[libbydiesel]

With the camshaft removed, all valves will be closed.  Do the lifters all look the same height?

Rotate the crankshaft through two revolutions to ensure that there is no contact from a valve hanging open.  After that, test compression on #1 again.  Without the valves opening/closing you will not get a normal compression reading but it should be more than 5 psi.  If still reading 5, then the next thing I would do is pull the head. 

The real oddity here is that the issue has come and gone. All the explanations I can think of are fairly far-fetched.  Best of them is that a valve is hanging open maybe from a lifter overextending. 

[WeekendMechanic]

With the camshaft removed, all valves will be closed.  Do the lifters all look the same height?

Rotate the crankshaft through two revolutions to ensure that there is no contact from a valve hanging open.  After that, test compression on #1 again.  Without the valves opening/closing you will not get a normal compression reading but it should be more than 5 psi.  If still reading 5, then the next thing I would do is pull the head. 

The real oddity here is that the issue has come and gone. All the explanations I can think of are fairly far-fetched.  Best of them is that a valve is hanging open maybe from a lifter overextending. 

Yes I measured all lifters to be sure, and are all the same height.
I did what you said I turned twice nothings hanging did the test again but i`m still getting 0 psi on 1 cylinder.
I took the oil pan off, underneath the piston look good and no hole.
I did find some metal in the bottom of the pan no large pieces just very small filings.
I`m really confused now I don`t understand why its 0 psi.
 

[libbydiesel]

Next up would be to pull the head.  Tip it up on its side so the intake and exhaust ports are UP.  Pour or spray some solvent into the intake and exhaust port of the offending cylinder.  If it pours right back out of one of the valves, you have likely found the culprit.  If there is only a tiny dribble or no leakage at all, then pull the piston/rod and inspect.  With 0 psi something should stand out.