supawyde

I have a 1.8T A4 with 150,000. I recently had my timing belt done however shortly after, my car started to sound like a diesel truck engine. I got the code "Cam Shaft position actuator A-bank one timing over-retard". I really don't feel like taking the car back to the original guy that did the job. Stealership said it was a 5 hour job ($600-$700 assuming I don't need parts). I also have the catalytic converter check engine but that's nothing new. I put aftermarket cat and O2 sensors (bad move).

oceanbreeze

can you elaborate on what "shortly after" means -- 10, 100, 1000 miles?

engine code and MY would be useful too.

the actuator refers to the VVT feature of the the cam adjuster. check if it is plugged in, or remove the connector and check for dirt. The car should still run if the adjuster solenoid is not plugged in, but when the ECU commands it to move to effect intake cam advance/retard, it will see that it has not done so because the cam position sensor will continue to report the same timing info.

Beyond that, hopefully less likely, it could be that:
- the solenoid went bad (if you already have a CEL on you'd need to scan it all the time to detect exactly when the new code got registered in fault memory);
- the tensioner itself is going bad due to pad wear, or other internal failure;
- your oil pressure is so low that the tensioner cannot extend properly;

The dieseling sound is a typical sign of a failing tensioner, worn pads, or low oil pressure especially when hot.

there are two types of timing on this engine:
- static: the timing belt, and cam chain with tensioner
- dynamic/VVT: the cam chain tensioner/adjuster/actuator

If for some reason the timing belt was installed off by a tooth or so you need to fix it. It's not the most difficult DIY in the world, if you feel up to it.

You probably know this already, but the cat and O2 sensors are rather important on most modern engines and not just for keeping the air clean. There may be some aftermarket ones that will work as this car expects them to, but obviously the ones you got are probably not it.

HTH.

lyleswk

All good info, but I think it is a simple matter of your mechanic not paying attention and letting it slip a tooth. Oceanbreeze's timing question is key. I have done 2 on the 1.8; one didn't move and the other did. I was glad I had marked the position and counted teeth before I started. If you have a relationship with the original guy, get him to fix it. If not, I wouldn't take it back...ever. I would drive it very carefully because if you have predetonation going on, you could easily damage the engine.

supawyde

I've been reading up quite a bit and most cases it seems that the timing is in fact off by one tooth. Getting it fixed this weekend. Unfortunately I have been driving it like this for at least 10 days. Hopefully I haven't or won't do any additional damage. Thank you for the info

oceanbreeze

Don't drive the car in this state. In fact, don't run it, or crank it with the starter even. Unplug the negative on your battery and don't plug it back in until this is fixed.

You don't know factually what the problem is. if it's just the TB that was installed one tooth off AND that is the only problem on your timing, it's fine. One tooth off is not going to cause any damage. Two teeth off probably won't cause any damage either. These engines have some tolerance there.

If it is the tensioner, that is a much much more serious problem. it does not fail in discrete step-wise fashion like a timing belt jumping one tooth does.

You already have the warning, so you have lost the ability to know if it is getting worse than it already is. You won't get any additional warnings if you are getting closer and closer to bent valves.

Also, when you take things apart, do it slowly and along each step investigate each part for possible signs of wear or failure (think forensics here). When you get to the timing belt, first determine that it is indeed off (and by how many teeth, and in which direction). If it looks like it is set correctly, take a break, go do something else, then come back and re-confirm. Post some pictures if in doubt. If the belt is okay, you will need to diagnose what else might be causing the off timing.

oceanbreeze

Oh, one more thing. You may need new parts if something is worn, damaged, or failed.

normally, you want to take this back to the shop to have them correct it unless it's some creepy guy or a cash deal, or something like that. then, definitely fix it yourself, or take it somewhere else. but it gets more complicated if some part has failed and you want a replacement under warranty.

supawyde

Thank you for all the good info and advice. Mechanic says I need a valve cover gasket and the timing chain tensioner gasket at the back of the head. Hopefully I don't get price gouged and my car trouble is resolved for a bit. Oh, the timing was reset and that part is thankfully resolved. Car sounds totally normal again

oceanbreeze

Great that you got the timing set properly.

Do the valve cover. It's worth the money, or do it on your own and save big. Make sure your PCV system is not clogged before you do all that though. A clogged PCV is what causes the VCG and tensioner seals to leak.

One of the worst side effects of a valve cover leak is that the oil seepage over time will coat anything and everything in the engine bay. That oil coating will make dust and road grime stick to it and work its way into everything. If you can, get an engine cleaning of some kind. Again, you can diy this and save (use brushes and some engine degreaser spray to work it in and loosen up the grime).

supawyde

Timing has been reset and valve cover gasket and tensioner have been replaced. The guy (mechanic doing side jobs) charged me $125 to reset the timing and then $100 for the gasket replacement. Decent pricing? (def compared to dealership). Feels great to have my 11 year old car back and running properly. Thanks for the assistance.