ALH Timing Belt Slipped.... now what?

[Reesetricted]

Back story, the car started running rough as I was driving down a street. I got to the light and confirmed my diagnosis, and pulled into a parking lot. It died. I tested compression and it came back good and even across all cylinders. I dropped the pan and check the rods bearing to make sure it wasn't rod knock, they looked outstanding for a 265k engine. It would start sometimes, and it would stay running, mostly, if you kept giving it throttle. However, it was making loads of smoke and running like crap. Seemed like it was off a tooth or so. I tried to start it 1 last time to get it into the garage... It started, then died in the street as I was turning around. No hints of starting since then.(It now occurs to me that I might want to do another compression test.) So, I tore I the timing belt replacement procedure. The PO told me the timing belt\water pump was replaced at 225k, I bought it after he rear ended someone at 235k(I had a Jetta front end waiting to go on this golf). Serpentine belt tension was totally useless and the tensioners slack bolt was rounded... Belt cut. As soon as I got the timing belt exposed enough to see it's tensioner, I knew I found the problem. So much slack. Belt is\was just floppy. It surely skipped teeth.

So, here I am... A guy with a bunch of tools and no VCDS. How do I go about timing everything up? I can't see any timing marks on the cam gear. Crank pulley has a mark, injection pump has a hole to lock it, flywheel has a mark.... But, without the cam shaft, the others don't do much good. Would one of you kind humans direct me to the instructions for re-timing this thing?

 

[Reesetricted]

All I've been able to find is " remove the valve cover, get the cyl 1 lobes in the upward V situation " and that should be TDC... Then I presume I'd adjust the crank and IP accordingly. I'm really flying blind. Any advice would help.

 

[Vince Waldon]

Yes, you need to pull the valve cover... to look for damaged/broken lifters.

Then you need to read the A4 Timing Belt procedure cover-to-cover... there's a couple special jigs required to check/set the timing:

https://www.tdiclub.com/articles/pdf/a4timingbelt.pdf

A great guide, with clear pictures for every step.

 

[tgray]

Slipping a tooth will not do great damage. I blew out a valve once with 2 teeth off but the engine was real loud before it let loose. I found the valve keeper blown out and the valve following the piston up and down - but no serious damage. It can affect the valves and lifters so the engine will run fine now but can crack things that fall apart later. The safest way is to pull the cam and inspect the lifters for hairline cracks and they are hard to see with the cam in the car. If any lifters are found bad it may be safer to pull the head and replace those valves. When a belt breaks is when things can get real bad. Especially when driving at highway speeds. Pull the cover. Check it out and may be advised to just put a new belt on but not the rollers. Slipping a cog may have done damage to the belt. Sure things will work and run when it goes back together with the old belt but the question is will it still be working at the next 100,000? Do the job and look for someone can help you with the timing after it is up and running.

 

[Reesetricted]

Thanks, guys. Im headed out of town, partially to scavenge parts from my other tdi, so, I won't be able to attack it for another few days. I'll report back with the findings. Hopefully not too much is wrong. If it is, whelp, the engine from my Jetta goes in.

 

[Mozambiquer]

That recently happened on my sister's alh. Only the injection pump timing was off. I reset the timing and it worked correctly, connected vag-com and set it spot on. Works great still. The problem had been that the person who had done the timing belt job had tensioned the tensioner backwards (it's a common problem, I guess) and so it got loose and let it jump a couple of notches.

 

[Reesetricted]

Alright, after much, much BS, I have it timed. Crank, cam, IP all good. It's running...pretty well. It's been so long since I've driven it I'm not 100% how it used to sound but, I'm like 90% sure it's a little more chattery than before.

All lifters looked flawless. The whole head looked near new, just like the bottom end.

I'm getting white smoke out of the tail pipe now. This is new...and somewhat concerning. I'm off to research that now. If you guys have input, lmk.

 

[Reesetricted]

BS= my tools being spread between 2 cities... A stripped valve cover bolt... And a stripped IM bolt. I replaced the IM bolts with hex heads and scavenged a valve cover bolt from my other engine(which I stripped a harmonic balancer bolt on). It's worth mentioning that I only use ball end sockets... And they still stripped. I already had all the tools necessary for the timing job. I just used a random 3 jaw puller I had for swapping the 5th gear for the cam sprocket. Worked 1st try.

 

[turbocharged798]

Alright, after much, much BS, I have it timed. Crank, cam, IP all good. It's running...pretty well. It's been so long since I've driven it I'm not 100% how it used to sound but, I'm like 90% sure it's a little more chattery than before.

All lifters looked flawless. The whole head looked near new, just like the bottom end.

I'm getting white smoke out of the tail pipe now. This is new...and somewhat concerning. I'm off to research that now. If you guys have input, lmk.

White smoke usually means retarded timing. Did you check IP timing graph?

 

[Reesetricted]

I don't have VCDS so, I have not. I just set the crank to right on the flywheel mark, with IP pinned in the notch, and the cam set, lobes up, with lock tool. Timing Belt was stupid tight but, per the "how to" saying "it make take a couple tries" I assumed it was supposed to be difficult to get the cam on. Also, I probably should've warmed it a bit prior to trying.

Any ideas how to fix it without VCDS m

 

[Vince Waldon]

The jigs get it close, but no way to dial in the timing other than electronically, with a tool like VCDS that can place the ECU in basic settings mode and properly map timing against fuel temperature.

 

[Reesetricted]

Wamp. Looks like a buying a dongle.

 

[Vince Waldon]

There's a list here somewhere of folks that have 'em, by city. Dunno how up to date it is, but can't imagine you're the only TDI home mechanic in Houston. ?!

 

[Reesetricted]

Actually, I'm in San Antonio. Splitting my time between Dallas and San Antonio at the moment but, go to Houston fairly often.

I was just thinking... Couldn't I loosen the bolts on the IP sprocket and rotate the pump? I assume I'd need to rotate it counterclockwise by... A very little bit. I'll look up the list in the meantime.

 

[Genesis]

IF -- and I repeat IF -- you have the cam lock in, the crank EXACTLY at TDC and the pin in the hole you should be EXTREMELY close *provided* you do the tensioning and tightening in the right order.

That is....

Cam sprocket on BUT NOT TIGHT -- just on, bolt in, but NOT tightened.
Tensioner not set.
Cam locked.
Crank locked.
IP pinned but bolts NOT tightened.

Now tension and lock the tensioner nut. You will notice the cam and IP sprocket moves JUST A BIT when you do that. That's NORMAL and expected. There is exactly ONE fixed reference when you tension -- the crank.

Remove the cam lock (you NEVER want to torque that sprocket with the lock in; if you load it you'll break the slot end of the cam.)
NOW counterhold the sprocket (DO NOT allow it to move!) and torque the cam sprocket bolt. Re-insert the lock - it should NOT have moved.

Check crank. TDC mark should be be BANG ON.

If it is, torque the IP bolts, remove all three locks, rotate TWO full rotations by the crank bolt in the direction of normal rotation (clockwise); you should feel only compression. Stop EXACTLY at TDC on the bellhousing mark.

The cam lock AND IP PIN should go in. If they do you're good and you do the above correctly you will be VERY close.

You do want VCDS to check it with absolute certainty and adjust it, but I would NOT attempt to tweak it without VCDS since you will no idea where you're coming from or going to, or where you wind up. VERY small movements of the IP sprocket move the injection timing point quite a bit.

 

[Reesetricted]

I did that, exactly as described by the directions. However, when I loosened the IP bolts, there was no movement as predicted by the how to.

 

[Reesetricted]

I mean, the car runs fine but, there eis def white smoke and there never has been. To be fair, I haven't driven it around. Just idled and revved in the driveway for about half an hour. I was waiting to reinstall the intake tube until after the car cooled down. It's easier from the bottom so, I haven't taken it off stands.

 

[Genesis]

There isn't always on the IP. What you usually have to do is "bump" the center nut (CAREFULLY!) to nudge it with the bolts just *somewhat* loosened. It's somewhat of an art to move it the tiny bit you want to get the timing where you want it and is VERY easy to go too far. Really, you need to know where you are -- the static setting only controls starting and the maximum adjustment the ECU can make; once case pressure comes up the ECU controls exactly where injection occurs within the limits available. The reason putting it "slightly advanced" (top half of the graph) is often preferred is that it gives the ECU a bit more advance range on the top end.

If you've got white smoke at idle after it starts I suspect you've got a hole that is not firing cleanly where there wasn't before, and that's not a good sign considering what happened. You definitely want the intake tube back on; the car cannot sense MAP and MAF correctly without the entire intake connected.

 

[Reesetricted]

Hmm, rereading your order, I'm not certain that it's the same as the order in the link above.

 

[Reesetricted]

Excellent point about the MAF. Ill get to a VCDS, one way or the other, prior to tweaking anything.

 

[Reesetricted]

I didn't check compression today, I will tomorrow. I had a bad glow plug (3, iirc) prior to this happening so, might as well.

 

[Genesis]

These engines will fire and run just fine with no glow plugs working down to around freezing temperatures. I had a harness that was fried for a while and because I lived in Florida at the time didn't bother fixing it. I couldn't tell it was not there, other than a small puff of white smoke on a cold start.

You're in Houston so..... same deal. That's not the problem.

 

[Genesis]

I did that, exactly as described by the directions. However, when I loosened the IP bolts, there was no movement as predicted by the how to.

There should be exactly ONE fixed reference when you tension the belt -- the crank which is locked. All the other sprockets float BUT the cam and IP themselves are both locked. The IP is pinned but the sprocket bolts are NOT tightened and the cam is not either.

Put the intake pipe back together before doing anything else. The ECU controls fueling based on its view of airflow and manifold pressure and it's not seeing the correct values with the pipe off.

 

[Reesetricted]

No, no... That's not what I meant. I meant, the code is annoying and I have spare glow plugs, since I can clear the code AND check compression at the same time, it's motivation. It'll also give me peace of mind knowing that the head\valvetrain isn't hurt.

 

[Genesis]

Yep.

 

[Reesetricted]

Hmm... I think I tensioned it with everything free. I need to look.

 

[Reesetricted]

Yea, I did it in the correct order... Or, I think I did. I believe.i followed the instructions to the letter.

 

[Reesetricted]

I sincerely appreciate the assistance, you guys.

 

[Genesis]

If the three IP bolts were tight when you tensioned timing can be quite-materially off. That also side-loads the teeth on the belt which is not a good thing to do in terms of getting the full life out of it.

 

[Reesetricted]

They were loosened but, I didn't see it move. Perhaps I should've tapped it.