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!

GTA_Driver

So basically cold idle is fine until the RPMs drop? What happens when you tap the accelerator to bring the RPMs back up?

When the engine is cold it doesn't take readings from the MAF, as far as I know. You could try disconnecting it and see what happens.

Another possibility is that your throttle body needs to be aligned/adapted. Ross-tech has a guide on performing throttle body alignment.


http://www.ross-tech.com/vag-com/cars/throttlebody.html

Prospeeder

yea They run pretty poor when the throttle gets out of sync if the battery is flat for a long time. So no codes huh. possible to have a large air leak? like forgot/broke the air injection hose on the side of the air intake thing next to the throttle body behind the engine. sounds like you did everything correct. If your scanner can do live data, look at fuel trim, is it really lean (trying to add fuel + numbers) or running really rich (trying to pull fuel - numbers)

Zaphodb17

Sounds like a vacuum leak...

jcman

Yes it does

tcdesignguy

When I was resetting the throttle body, I noticed the fuel pressure regulator vacuum hose was broken in half. So I went to dealer and bought 2 meters of the braided 3.5mm I.D. hose and replaced ALL the vacuum lines. Car started better and runs much better than before but still has a slight shake when sitting in the seat.

I hooked up the vacuum gauge again and now I am up to 14in vac at intake manifold. Green is 15-20. If I bump throttle to 950 rpm I am at 17in and smooth as silk. Note: the needle is very smooth on the gauge, no bouncing.

So I pulled the valve covers back off and set crank to TDC. Bank 1 marks are lined up perfect and the tensioner (original with replaced pads) is sitting up above the 2 metal prongs (guides).

Bank 2 (drivers) the exhaust cam is lined up perfect, but the intake notch is about 4mm to the left (toward intake manifold) of the arrow on the cam cap. I also notice the new tensioner I put in is sitting low. Well below the 2 prongs.

This must be my last issue. But I don't know what to do about it. I am sure if the chain was sitting at the proper height the intake mark would be on the money. Could I have done something wrong installing the tensioner? Do you have to prime a tensioner?

When I thought the engine was toast I put rotella T 40 weight in the motor, would that cause this? I was planning to swap back out to synthetic when done...

Thanks for any help!!!!

tcdesignguy

: So I went back out put tensioner tool in Cam tensioner with oil sprayed on the main shaft as It appeared to be dry compared to bank 1. After moving tensioner up and down a couple times with tensioner tool... It now seems to behave like bank 1 tensioner while rotating crank.... They both bounce up and down when I try and turn crank... That being said it still appears the new one I put in the main shaft that goes up and down doesn't get any oil on it.... If I look at bank one it is well coated with oil....

Does anyone have a picture of the cam marks on a 2.8 drivers side?

As it sits now timing looks pretty good... exhaust cam lined up perfect, intake notch is on the edge of the triangle mark... (not sure I can get any closer than that)

jseklund

I wish I could give you an answer on this - but the first timing belt I ever did was on my mom's car a little over a year ago. I had some problems and wound up replacing an entire head - oil wasn't getting to the head and the cams were chewed up, which I note because if you has a FLASHING oil light, then that usually indicates a lack of oil pressure not a level sensor. This could be a bad oil pressure sender, clogged pump, etc.

When I got my mom's car back together, it had the same rough idle and a pretty constant misfire on cylinder 4. I could never hunt it down. Tried swapping plugs, coil packs, fuel injectors, checked all vacuum lines, replaced some vacuum lines, adapted the throttle body a number of times, etc. I also popped the MAF from my car into hers. I checked for vac leaks with propane.

It would idle rough, with a somewhat noticable vibration at idle, but under throttle it would run fine. If I was at idle and goosed the throttle, it would be noticable as the car fell back to idle and would shake just a little more. The idle RPM were in the correct range and did not appear to be hunting at all.

Since she's been driving around and living with the idle issue - she had the flashing red light herself. She took it to a shop (I was busy) and they replaced the oil level sensor (which didn't work obviously), dropped the pan and cleaned it (which didn't work) and then I changed the sensor and it went away. Again, I only note this because of further similarity to your situation, which may just be a coincidence.

Also, you seem to have done everything right so this is just for confirmation - you did use the crank locking pin, correct?

jseklund

When you put the cam caps on, did you orientate them in the correct direction? If you pull one off and look closely, you will see a tiny hole on one side of the cap. If you look at the head, where the cap sits, you will see a similar hole. If you put the caps on upside down, oil will NOT get to the head. Pull one cap and make sure it is correctly turned. If it is, make sure all the arrows and numbers point in the same direction.

tcdesignguy

Here are images just taken from the car.... Is it possible my chain stretched? I could potentially have 16 link but have the intake cam off a bit due to stretch?




I am trying an icloud link to the photo

https://www.icloud.com/photostream/#A15qXGF1uzs6E

See if you can see the images