Hi everyone,

Thanks in advance for any help you can provide.

I have a 2004 Audi S4 Avant 4.2l (B6) with about 200,000 miles on it. The engine was fully serviced at 100,000 miles.

It has the timing chain slap issue at start-up, as well as a misfire issue with some of the cylinders.

I was driving it yesterday, went around a sharp corner, a red Low Oil Pressure message came on, and then the engine shut down.

I checked the oil and it was pretty low. I just had to put 4l into it to bring it back up to the minimum oil level. There did still appear to be some oil however.

I tried to start the engine a few times and it would crank but not start.

Ended up getting it towed to a shop, which unfortunately, can't look at it for two weeks.

I tried to start it again there and it did start, but ran pretty rough and then died.

It sounds like it's not getting fuel. Not sure if there's possibly an oil sensor that's cutting off the fuel pump. I believe I read something about that.

Now that oil is topped back up, I figured the fuel pump would work again, unless there's a sensor issue.

So, I'm wondering if anyone has any experience with this, and if it's possible that it's just a sensor issue, or if I've thrown the timing off and the engine is toast.

It didn't sound too rough prior to this happening.

I should have checked the oil prior to the 500 mile trip I just did, but had only changed the oil about 1,500 miles earlier and figured it'd be okay. There is an oil leak, and figured it burned a bit of oil due to the age, but not that much.

I've only owned the car for 6 weeks and 1,500 miles. I knew about the timing issue and misfires, and figured the engine was on its last legs.

The body and interior are mint and I only paid $2,500 for it, figuring that the engine would need to be replaced. Just not sure if now is the time, or if I can get away with a cheaper fix for now.

Here are the DTC codes - the ones with a dash- beside them are new since the last scan.

16395- (A - Camshaft Pos. Actuator Circ. Bank 2 Malfunction)
16405- (Bank 2 camshaft: timing change too late)
16556 (Fuel Trim Bank1 System too Rich)
16558 (Fuel Trim Bank2 System too Lean)
16559- (Fuel Trim Bank2 System too Rich)
16684 (Random/Multiple Cylinder Misfire Detected)
16685 (Cyl.1 Misfire Detected)
16686- (Cyl.2 Misfire Detected)
16687 (Cyl.3 Misfire Detected)
16688- (Cyl.4 Misfire Detected)
16689- (Cyl.5 Misfire Detected)
16692- (Cyl.8 Misfire Detected)
16725- (Camshaft Pos.Sensor Circ Range/Performance)
16885 (Vehicle Speed Sensor Range/Performance)
17535 (Long Term Fuel Trim mult. Bank1 System too Rich)
17537- (Long Term Fuel Trim mult. Bank2 System too Rich)
17538 (Long Term Fuel Trim mult. Bank2 System too Lean)
17546- (Long Term Fuel Trim Add.Fuel Bank2 System too Lean)
17831- (Crankshaft-/Camshaft Pos.Sens.Signals Out of Sequence)
17748 (Sec.Air Inj.Sys. Bank1 Flow too Low)
18062 (Please check DTC Memory of control panel ECU)

Any thoughts or suggestions?

Thanks again!

Colin

Addendum: As I've organized the DTC codes and can see it all at once, it looks like it's a timing issue for sure. All of the new codes with a dash seem to indicate a failure. Damn.

 

The cam chain tensioner has failed or had lost the plastic pad (or pads) so the timing is off. Hopefully it has not jumped time and bent any valves. You have a vacuum leak somewhere too. Probably a PVC valve. It's probably not starting because the timing is so off due to the cam chain tensioner.

You might get lucky and save it but running the things low on oil isn't good. The 4.2's take about 8 quarts to fill so being about 4-5 quarts low is really not a good thing at all. The ECU may have shut it down on its own to save the engine.

Have a compression check done on the each cylinder to make sure no valves were bent. If not, that's a good sign. Second, drain the oil and if there is a lot of light colored metallic sludge in the oil, you may have done some bearing damage. However, if the engine shut down happened almost immediately after the low oil warning light came on, there is hope. If you have any bent valves, you're going to have to pull the heads and replace them.

I just replaced the cam tensioner in my D2 A8 4.2 myself. It cost me about $500 in parts. Labor, would have probably run $2000 easy.

The first order of business is replacing the tensioners (do both sides and you should go ahead and replace the timing belt and water pump, at minimum, since all that is going to have to come out anyway) may fix the issues. Pulling the cams during this process will determine whether there is bearing damage as if there is any scoring on the heads where the cams ride, you will see it.

Anyway, if there are no bent valves and bearing damage, it certainly is very fixable. But for God's sake, man, keep oil in that baby....

 

Thanks for the reply, Dave. Appreciate you taking the time.

That's about what I was figuring unfortunately.

Yes, I am kicking myself, big time.