tcdesignguy

Background: 99 A6 2.8L 200K miles well cared for. 2 weeks ago i kept getting flashing oil symbol on the dash, pulled over checked and oil level fine and it turned out to be sensor was going bad. Ordered new sensor but before it could arrive I hit a chunk of concrete on the hwy and cracked oil pan in 2 places. Well I didn't know the pan was cracked and loosing oil, I though the impact just jarred the sensor. 2 miles down the road when I pulled into my driveway I could feel something was wrong and shut down. After I stopped another quart drained out. BAD LUCK.

So we pushed it into the garage, put a new lower oil pan on, filled with oil ran for 5 minutes (It took a good minute to get it to start, once started had a really rough idle) then I drained into a brand new catch pan. Shined a super bright light in the oil to see how much fleck was in there. Not too much in there.

Drove it around a little and flushed oil again, not much more metal fleck came out, but idle did not improve. So I started checking things...

Compression check: All cylinders are 180-185psi
Vacuum gauge (at intake manifold T into blue connector) 8" and fairly steady on a large diameter gauge.

So as far as I understand good compression and low manifold vacuum is timing is off. I took it to a europsport shop to plug into laptop. Misfire cyl 4,5,6 (Bank 2 Drivers Side U.S)

Pull off valve cover to find the top plastic guide on the Cam tensioner has been chewed. I pulled pieces out.

I decided to order timing belt, water pump, thermostat, gaskets and seals since I was digging into the car this far.

Replaced Bank 2 Cam tensioner with a new one after pulling both exhaust and intake cams out. Chain links = 15.5 roughly on drivers. side.

Bank 1 was fine, and had no intension of touching except with a mirror I could see leaking behind on the seals. WHen I tried sneaking the half moon seal and metal gasket under the tensioner the stupid tiny mesh filter fell out. So I removed both exhaust and intake cams on Bank 1 as well. replaced plastic guides and filter, plus all seals and gaskets. Chain links = 16 exactly.

In order to secure the cam caps I allowed the cams to rotate counter clockwise approx 15deg so the lobe was pointing straight into the lifter. (IF i set the cams correct, I could't get the #4 cam cap started without fear of initial thread damage. ) Once I snugged the cam caps I used the CAM alignment tool to rotate the cam clockwise to correct timing position. no interference was felt other than from number 4 exhaust cam lobe

So with all cams set correct and timing belt plus everything else installed i rotated the engine using 24mm 12point socket on crank 4 times. I was easily able to reinstall the CAM BAR meaning the timing is correct as far as I understand. (I guess it just guarantees crank to exhaust timing).

Put it all back together, hook battery back up and the car starts right up. no check engine light, cold high idle fine. Once the idle drops it is a rough idle. UGH!

I have run the car for 20 minutes, no check engine lights. It is dead smooth from 950 rpm's up.

new spark plugs installed (NGK) at beginning of job


I recheck vacuum and now it is only slightly higher than before at 10"!!!!!!!!!!
I checked and I did plug the secondary air pump back in.
Confirmed Vacuum connections were made to the valve covers...

I AM TOTALLY LOST AS TO WHAT THIS COULD BE. If I had a bad lifter the vacuum gauge would fluctuate when it got to that one. THe gauge is very smooth.

I swear it has to be something stupid. I haven't finished burping coolant yet, but I doubt it would cause this. I have lots of pictures if need be to try and solve this..... If I did damage the head (valves etc) how could I still have good compression??

ONE MORE CLUE POSSIBLY: THe engine sounds different now when I turn to over before it starts. Different than it has ever sounded in the past. Not sure if the computer was unplugged how long it would take for things to adjust?

Thanks in advance!

tcdesignguy

UPDATE

On another site someone suggested resetting throttle body,, by disconnecting battery, reconnecting and turning key to on.... Here is what happened..

I tried it as soon as I got home tonight. Disconnected battery. went in and had dinner, came out and reconnected battery. Then turned key to on position. Throttle body made weird noises for approx 30 seconds then quick.

Car wouldn't start... It turned over straight for 15 seconds. went out to inspect engine compartment to find i hadn't plugged in MAF or other connector at the air box (although i don't know if that was cause. key off, key on after a little bit it would fire, stumble and die after achieving about 300rpm. After about 15 times of this I depressed petal to floor and got it to go. it sounded like it was running on 5 cyl for a few seconds then took off.

It was flashing Check engine during this phase (i assume active misfire).

Am I to believe now my timing is STILL off??

tcdesignguy

UPDATE

On another site someone suggested resetting throttle body,, by disconnecting battery, reconnecting and turning key to on.... Here is what happened..

I tried it as soon as I got home tonight. Disconnected battery. went in and had dinner, came out and reconnected battery. Then turned key to on position. Throttle body made weird noises for approx 30 seconds then quit.

Car wouldn't start... It turned over straight for 15 seconds. went out to inspect engine compartment to find i hadn't plugged in MAF or other connector at the air box (although i don't know if that was cause. key off, key on after a little bit it would fire, stumble and die after achieving about 300rpm. After about 15 times of this I depressed petal to floor and got it to go. it sounded like it was running on 5 cyl for a few seconds then took off.

It was flashing Check engine during this phase (i assume active misfire).

Am I to believe now my timing is STILL off??

Prospeeder

you might not have wanted to do that. they run horrid when the throttle controller is bad, or not aligned. you really need a vagcom on a laptop if your gonna do alot of your own work on your audi. i have doubts the timing is off. One tooth on either chain wont make it run like your saying.

tcdesignguy

hmmmm great. I am working on getting the VAG-COM as we speak. Ordering the USB connector to OBD2 today off ebay.

tcdesignguy

For my own sanity I am going to pull off the valve covers again, recount and check timing at TDC.... I don't know what else to go after. At least it finally through a code so that can help once I get the VAG-COM

bydand

ONE MORE CLUE POSSIBLY: THe engine sounds different now when I turn to over before it starts. Different than it has ever sounded in the past. Not sure if the computer was unplugged how long it would take for things to adjust?

Can you explain this bit a little more?

What is different! The engine noise (mechanical), induction noise (air), exhaust (gas) ???
Or just the misfire from Cyl 4,5,6.

The HT leads are plugged back in correctly (all the way in) into the plugs and into the coil pack?

You haven't dropped oil behind the rocker cover and filled the plug pocket with oil.

The vacuum pipes are good and not leaking? I would change them for silicon tube anyway if you have not already.

tcdesignguy

I think timing must have slipped somehow when I did the job..

I reran compression tests and bank 2 cold is ~95 psi. Bank 1 is 155psi And when I start the car and go to the tail pipe very little flow is coming out, comparing to bank 1 exhaust.

When I started the job all cyl were 180 cold (@70degree garage temp)

When I reset timing the second time since I was just working with the cam tensioner etc I didn't put the crank pin in, then when I put tension on the timing belt the pulleys where already locked back to the cams. When I realized I did it in the wrong order i popped the cam pullies and retensioned belt and torqued the pullies after.

I wonder if the crank didn't rotate slightly when I tensioned it the first time while the cam pullies where locked. UGGH. I was pretty careful.

I even turned engine over a bunch of times by hand then by key to check and marks seemed good except the intake cam bank 2 was a tich ahead of the cam cap notch.

Prospeeder

I think you timing is off. I had a tuner shop call and asked me to come down and see why the cam codes wouldnt go away on the S4 he was building. He swore 16 teeth between the marks, but i looked and saw 17. He stared and stared and could not see how i ever could see 17. I had him move it over a tooth, was perfect no codes.

tcdesignguy

Correct. Apparently I cnt count to 15.5! Again most everyone including myself is confused on how to view the cam notches, and where to count the 1st pin on the chain. It is easier that I thought to be off that 1 tooth on the sproket.

If your 2.8 idles like crap after chaanging a cam tensioner, and you suspect timing it probably is your chain timing. especially if you used the proper tools to align cams to do the timing belt job.

Also you'll have a clue in that the bank that is misfiring will have around 90psi compression cold instead of 150-180psi because your intake duration is messed up.

Moved the intake back 1 tooth, and it runs absolutely perfect. Smooth idle and all.


Steve C