Bye-Bye Timing Belt!!!!!

[Daft]

Yep that's right. I had a timing belt issue this morning on my way to work.

I was accelerating down a straight piece of road when my car made a "POP" and the rpms dropped like a ton of bricks. Shortly there after the oil light came on. The good thing is that I never heard any clacking that one would hear when the valves are wailed on by the pistons. I can only hope at this point that my valvetrain survived the failure.

I started taking the car apart after the flatbed driver dropped me and the car off at home. I got as far as removing everything up to the lock carrier so, I'mm haveto finish removing things tonight to get a good look at the problem. I hoping that the belt jumped timing just enough to loose compression and piss of the combustion cycle.

On a side note, my timing belt is only 1.5years old and has about 35K miles on it. I changed everything I possibly could when I did the job in 2003 so, it's a major surprise to me that something went wrong like this.

Hopefully I can order my parts tomorrow from ECS to get them for Monday and get my timing assembly together again.

[RedRocket]

holy cow...

You just got that thing all fixed up!! Damn...

Now I'm pissed.

This is why my next car will be a lease. If it's fken broken, the dealer will give me a spare car and fken fix it. Done.

damn....

[bitterchild]

maybe ecs will give you a tensioner at cost since you bought one from them and it went within 35k. If it weren't you I would suspect incorrect installation. More specifically allowing the tensioner to fully compress of uncompress.

[marked001]

damn...wtf.... no luck for you lately!

[RedRocket]

Originally posted by bitterchild
More specifically allowing the tensioner to fully compress of uncompress.

Bitter what do you mean by this? (I just did my timing belt and want to assure myself that I didn't fk-up)

[Daft]

I dunno about ECS hooking me up. I do actually have my receipt from when I bought all my TB parts. I bought everything on 4/25/03 from ECS. I'll have to ask them what they can do. I know Audi won't do a thing because I did the work.

I'm pretty confused about what caused this though. My car always runs great and this was extremely sudden and not under full boost by any means. I betting that the belt or auto-tensioner was weak and today was the day that put it over the edge.

[Daft]

Originally posted by RedRocket
Bitter what do you mean by this? (I just did my timing belt and want to assure myself that I didn't fk-up)

When you install the new auto-tensioner, it is fully compressed with the pin holding it. Once you remove the pin, it begins to extend its piston slowly by the force of the hydraulic pressure in the tensioner body.

After you pull the pin, you should rotate the engine by hand several times and line the crank back up again to see if you cam sprocket is still lined up. Not doing this extra step can lead to incorrect timing because the tensioner can become a bit tighter/slack after it has fully extended.

[marked001]

what's the belt look like? any wear or anythign? or jsut a nice clean random break?

[joeya103]

man that sucks to hear that daft...

kind of making me worried about my timing belt. had it done by a family friend mechanic who normally does volvos. hopefully he didn't mess it up!

[RedRocket]

Originally posted by joeya103
man that sucks to hear that daft...

kind of making me worried about my timing belt. had it done by a family friend mechanic who normally does volvos. hopefully he didn't mess it up!

I wouldn't worry man, worrying a waste of time.

[alen]

Originally posted by Daft
After you pull the pin, you should rotate the engine by hand several times and line the crank back up again to see if you cam sprocket is still lined up. Not doing this extra step can lead to incorrect timing because the tensioner can become a bit tighter/slack after it has fully extended.

Now you tell me that! jk

I'm surprised it gave way after only 35k but give us an update on what actually went wrong.

ANd didn't you just work on your turbo?

[Daft]

I haven't gotten to the TB yet. I still have to remove the lock carrier and the accessory belts first. I had to go to work so, that's where I left it this morning.

I will find out after I get home though. I'm really curious at this point. Pissed too but, curious.

Alen: Yeah, I just buttoned up the turbo on Sunday night and the car has been running great. Figures....

[Audimarc]

It should have happened to someone else. You're good people Daft.

[duhvinci]

Lets hope that there is nothing serious! Been there otherwise

[bitterchild]

Originally posted by Audimarc
It should have happened to someone else. You're good people Daft.

on the contrary, daft is well equipped to diagnose and knock out this issue quickly. now i'm not saying anyone should meet such misfortune but... daft is good people though, you're right about that.

[Daft]

Ok. I removed everything down to just the timing belt and it's rollers/pulleys. The belt is in one piece. The auto-tensioner is fine. The engine turns properly by hand and I can stop the crank at the timing mark on the block and the cam sprocket matches up. This car still has good timing. WTF??!?!?!?!?!?!?!


Now, let me retrace my steps here.

Under medium acceleration, there was a "POP" and then the car went dead, oil light came on and warning beeps sounded.

I connected my laptop while I was waiting for the flatbed and there were no error codes at all. I figured that it had to timing related.

I have checked all my hoses after the turbo:

compressor to hard pipe
hard pipe to IC
IC to throttle body

All the hoses are 100% AOK.

I've rotated the motor by hand about 100 times tonight and it feels smooth and I can't hear anything wrong with it's movement. I get the nice puff of air into the exhaust manifold on each piston's exhaust stroke.

I couldn't have broken a rod or a wrist bearing, I'd have a some noises in the block from the lame rod hitting things. Perhaps the Cam Position Sensor broke? I'll have to take it off and inspect it. Otherwise, I could say that the cam chain snapped but, I am getting intake/compression/exhuast from all the cylinders.

I have to do a compression test and see what I've got but, I really can't see how a valve could be bent.

Can anyone think of anything that I haven't checked other than my compression? .

I'm really relieved that my timing belt didn't break but, I won't rest until I know this car is going to work again.

[k0mpresd]

maybe check your oil line connects for your turbo...?

since you obviously lost oil pressure for long enough for the light to come on

[Daft]

Yeah, that's in good shape. I just put the line back on the replacement turbo on Sunday night.

I'm pretty sure that the oil pressure light went off because the motor stalled while I was moving and the oil pressure was less than the sensor expected.

[Daft]

Does anyone have any other suggestions on what I could check?

I'm going to put the car back together tonight and see if I can get it to run.

[k0mpresd]

i dont really have a suggestion on what to check other than that it has to be something on the intake/engine side..post TB

something simple like a hose blowing off would just cause the car to go into vacuum from boost and should cause it to stall

maybe pull the valve cover to make sure nothing looks screwy in there..??

i would do a compression check anyways

[Burntaudi]

I'm guessing a hose popped off somewhere. I had something simular happen a couple of times and in both instances it was a hose close to the turbo. The car would still run after it died but it would sputter and buck if I tried to drive it.

[Daft]

Originally posted by k0mpresd
i dont really have a suggestion on what to check other than that it has to be something on the intake/engine side..post TB

So you mean the intake cam? or maybe the cam chain? That would surely cause the intake valves to stop moving but, the engine is ingesting air and pushing it out when I rotate the motor by hand....odd.

I'm going to leave work early and get the car back together and do a compression test. If it passes, I'm really going to be stumped.

[Daft]

Originally posted by Burntaudi
I'm guessing a hose popped off somewhere. I had something simular happen a couple of times and in both instances it was a hose close to the turbo. The car would still run after it died but it would sputter and buck if I tried to drive it.

I thought that too but, I checked all the charge air hoses from the compressor outlet to the throttle body. Everything is solid and hole free.

When I got the car home yesterday (before I took it apart), I tired starting it and it wouldn't start. I did get a couple pops though.

[Audi A4 1.8T]

oil pump?

[alen]

check if your bpv popped out. other than that, nothing that you didn't already mention didn't come into mind.

[Starting]

wow that is crazy. I was thinking it was an oil problem at first but if you can turn it by hand with no problems nothing is seized. I really have no idea but I would just check the basics. Make sure it's getting fuel and spark. Maybe the ICM went totally dead?

[Lapkritis]

Could you describe the "pop" a little better? Was it an intake backfire? If that's the case then start checking the basics, starting with fuel pressure and injector firing first and then coils/spark. You'll find it, it's just an audi not a space shuddle. ;)

[bitterchild]

Originally posted by Lapkritis
You'll find it, it's just an audi not a space shuddle. ;)

it isn't a space shuttle that's for sure

[RedRocket]

Originally posted by bitterchild
it isn't a space shuttle that's for sure

ooooh looky who's the new spell checker....

[Daft]

Originally posted by Lapkritis
Could you describe the "pop" a little better? Was it an intake backfire?

I know this is going to sound rediculous but, I can vaguely recall the "POP" noise it made. I was cruising at about 3500rpms and I laid the gas down about 3/4 and started to make a little boost. Then suddenly, POP! and the car just died as if the key was turned off.

The pop itself sounded like when a hose blows off or apart (like popping a ballon) but, all my hoses are perfect.

Obviously, I have all the procedures to check all the components but, I lack all the "VAG test harnesses" that they suggest to use for checking signals on all the sensors and components around the engine bay.

I'll tell you what though, I'm checking the CMP sensor first. Usually when a crank/cam angle sensor goes bad the car shuts right off and won't spark until it works again. THe ECU needs the CMP to know when to fire. No cam position signal, no fire.

That's my guess for now.

[Lapkritis]

haha, guess I better give back my diploma from 3rd grade

[nramsey]

Check all the fittings on the intake manifold are tight. It sounds to me like a massive vacuum leak between the throttle body and valves. Brake booster hoses all still connected and tight?

I think (hope) the oil light just came on when the car died because there was no oil pressure once the engine stopped. I think the same thing would happen if you stalled it yourself. If that pop were something mechanical you'd definitely notice noise or grinding or something while turning the engine I'd think. I think a compression test would be a great idea though just to put your mind at ease that the engine itself is good to go.

[RedRocket]

Originally posted by Daft
I know this is going to sound rediculous but, I can vaguely recall the "POP" noise it made. I was cruising at about 3500rpms and I laid the gas down about 3/4 and started to make a little boost. Then suddenly, POP! and the car just died as if the key was turned off.

The pop itself sounded like when a hose blows off or apart (like popping a ballon) but, all my hoses are perfect.

Obviously, I have all the procedures to check all the components but, I lack all the "VAG test harnesses" that they suggest to use for checking signals on all the sensors and components around the engine bay.

I'll tell you what though, I'm checking the CMP sensor first. Usually when a crank/cam angle sensor goes bad the car shuts right off and won't spark until it works again. THe ECU needs the CMP to know when to fire. No cam position signal, no fire.

That's my guess for now.

I guess you can unplug it and see if a code comes up?