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Old 05-17-2014, 12:17 PM   #1
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Default 2002 Audi A6 3.0 Basket Case or Basic Repair?

To those of you who frequent multiple Audi forums, I apologize in advance for the redundancy. I have posted this question on several forums in hopes of getting maximum feedback.

This is the first time I have ever posted a question on a forum. I am a career lurker, and forums have been of tremendous help to me with other vehicles. I have scoured the Audi forums, and gathered a lot of information, but havenít really been able to come up with a clear direction for troubleshooting my latest challenge. I am hoping the Audi community will be as helpful as other automotive communities have been, and will give me some guidance.

At 45 years old, I have owned many cars. With the exception of mounting and balancing tires, alignments, exhaust, and machine work, I have done every repair on every car. I have owned foreign and domestic, cars and trucks, and have done repairs as involved as replacing the top end of a Ford Taurus, replacing the transmission on a Ford F150, and replacing the timing belt and steering rack on an Acura RL. I currently have two BMW 3-series, both more than 10 years old. Not trying to pat myself on the back, just giving a point of reference on my level on mechanical aptitude. I like owning and driving older luxury cars. It has worked out well for me, and I have had great success maintaining them at a reasonable cost.

Five days ago I bought a 2002 Audi A6 3.0 Quattro. The guy I bought it from (maybe in his late-20s) got it from his father a couple of years ago. His father was the original owner. The guy gave me all of the maintenance records, and it shows that during the time his father had the car, it was meticulously maintained, and all at the dealership, with the exception of a couple of more recent repairs (serpentine belt, exhaust camshaft at 1,2,3 cylinders, mass air sensor, and coolant temp sensor Ė all done in January 2013 at a different shop). All routine maintenance was done, all the recall work, plus misc other repairs. When I bought it, the CEL was blinking. The car started fine and ran alright (I have no point of reference, since I have never owned an Audi), but was noticeably rough at idle. I had the codes pulled at Advance Auto Parts before I bought it. It came up with the common misfire codes Ė P0300, and misfires on all cylinders.

Here are the details of what has happened over the last several days.

Tuesday
Drove the car home, approximately 15 miles. I think the CEL was blinking the whole time.

Wednesday, Thursday
Bought an OBD reader. Pulled codes (the same) and cleared them. Reset the codes, drove around, and pulled codes again. Repeated this cycle a few times. The P0300 and the 4,5,6 cylinders codes seemed to come up first, but they all came back up eventually. Sometime the CEL was off, sometimes it was solid, and sometimes it blinked. I couldnít identify what variables made the light status change.

Friday
Did compression test. Results were: Cylinders 1,2,3 (passenger side) were all right about 180 psi, cylinders 4,5,6 (driverís side) were right about 130-135 psi. Spark plugs looked fine when I pulled them, but plugs from cylinders 2 and 3 had oil on them. I already knew that I had an oil leak at the valve cover gasket, so the wet spark plugs were not a big surprise. I also noticed that when I pulled the wire harnesses off of the coil packs, the locking mechanism was broken on many of them, and the screws that secure the harnesses to the engine were missing.

Noticed that a t-fitting near the front of the engine didnít have a vacuum hose attached to one of the nipples. Found that the hose that should be connected had fallen behind the timing belt housing on the driverís side. Hose is damaged, so I didnít try to reconnect. I am going to order new hose and replace it and others. In the meantime, I taped off the open nipple in hopes that it might change something.
I drove it after the compression test and got a new code Ė P1296. Did the research and determined maybe itís the coolant temp sensor, although it was just replaced a little over a year ago.

Saturday
Decided that since the compression test came out OK (although I donít know why there is such a difference side-to-side) that I would pay the sales tax and transfer the title Ė my commitment to keep the car.

With license plates on it, I decided to put it back on the road. I ran an errand to a location approximately 10 miles from my house. About 4 miles of the trip were on side streets, and the other 6 were on the highway. I actually kept my OBD reader plugged into the car the entire time, so I could continue to check for codes. CEL was blinking most of the trip there. The exception was when I exited the highway. As I was exiting, the CEL went solid, and stayed that way almost the rest of the trip (just a couple of miles). There was also a short time at the beginning of the trip where the light was off.

When I came back to the car, I pulled codes again. Got the misfire codes, but also got P0118 Ė Engine Coolant Temp Sensor 1 Circuit High. I reset the codes.

I tried to start the car. For the first time, it was reluctant to start. I was able to get it started by flooring the gas. When I let off the gas, it was idling at about 3000 rpm. I tried tapping the gas pedal to see if it would drop the idle, but with no luck. I turned the car off and tried to restart it several times. Sometimes it would start, and then stall, sometimes it would start but idle at high RPM, and sometimes it just didnít seem to want to start at all.

After multiple attempts, I was able to get it started and get it to idle in the normal range. I (fingers crossed) headed for home. Again, the CEL was blinking most of the way; although a couple of times on the highway it went solid. After I exited the highway, a cycle seemed to start. About every ľ to Ĺ mile, the light would change from solid to blinking, then back to solid a ľ to Ĺ mile later. The cycle continued the rest of the way home (a few miles).

I got the car home and parked it. Now Iím looking for help. I want to keep the car (cosmetically it is beautiful), and I have the ability and the money (within reason) to repair and maintain it. Anyone have any ideas on what my best next step should be? Thanks in advance for the help!
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Old 05-17-2014, 12:35 PM   #2
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Wow quite a story!

Two things I would caution you on, first if the cell is blinking don't drive the car unless you don't care about burning the cats down and second of all a vacuum leak will cause misfires and crappy idles.

The cts coolant sensor could be bad even though it was replaced and it is not that difficult to replace, some brands are known to be substandard in quality.
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Old 05-17-2014, 03:12 PM   #3
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BTW, at least the passenger side camshaft was replaced as they have been known to eat lobes that year "more so".

You don't have a basket case just a little understanding of the Audi way of engineering and some minor repairs to get past these issues, you never mentioned the miles on the clock?
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Old 05-17-2014, 04:06 PM   #4
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Originally Posted by jcman View Post
BTW, at least the passenger side camshaft was replaced as they have been known to eat lobes that year "more so".

You don't have a basket case just a little understanding of the Audi way of engineering and some minor repairs to get past these issues, you never mentioned the miles on the clock?
Sorry, missed an obvious detail. Just under 147,000 miles.
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Old 05-17-2014, 04:44 PM   #5
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Sorry, missed an obvious detail. Just under 147,000 miles.
You've got a few good miles left on her based on the care of the other owner and that of your own, hope you have some thick skin here regarding some of the comments about the 3.0, it's not one of the most accepted centerpiece power plants in this forum and I have one.
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Old 05-18-2014, 04:40 AM   #6
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Your mistake is here:

Quote:
Originally Posted by CBVaughan View Post
Decided that since the compression test came out OK
Do a leak down test and check the cam timing.
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Old 05-18-2014, 05:54 PM   #7
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Your mistake is here:



Do a leak down test and check the cam timing.
^^^That is a good thing to do, especially since one side had low compression.
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Old 05-18-2014, 06:12 PM   #8
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^^^That is a good thing to do, especially since one side had low compression.
Agree on that to do again but with three codes non-related to cam timing checking timing would not be needed, four cam position sensors on the 3.0 comparing the crank position and if something is out of phase those codes will be present.
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Old 06-01-2014, 05:04 AM   #9
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OK, so here's the latest.

After replacing all of the vacuum lines/fittings, the check valve and the coolant temperature sensor (they all needed to be replaced anyway, and I think the breakdown of the vacuum lines/fittings is what caused the car to go from running rough to almost not running at all), I did the leakdown test. I bought a new, US General leakdown tester from Harbor Freight. I have never used a leakdown tester, and due to some wild inconsistencies in readings, I didn't have a ton of faith in the accuracy of the tool or my technique. For this reason, I took as many as 10 readings per cylinder to try to establish trends. Here's what I got:

Cylinder 1 - 30-35% leakage - leaking sound seemed to be coming from the left (other side) head area

Cylinder 2 - 85% leakage - leaking sound was coming from the area where the leakdown tool hose screwed into the spark plug hole

Cylinder 3 - 40% leakage - leaking sound seemed to be coming from the left (other side) head area

Cylinder 4 - 50-60% leakage - leaking sound seemed to be coming from the left (same side) head area

Cylinder 5 - 32-36% leakage - leaking sound seemed to be coming from the left (same side) head area

Cylinder 6 - 22-35% leakage - leaking sound seemed to be coming from the left (same side) head area

Other relevant info:

I removed the upper timing belt covers and both valve covers before doing the testing. I visually inspected the camshafts. One of the lobes on the right exhaust camshaft is noticeably rounder than the rest (the others look great - nice points), but I doubt if it is worn enough to cause all cylinder misfires. Also, this is the camshaft that was just replaced 10,000 miles ago. There is also a worn lobe on the left camshaft, but again, it it just slightly rounded.

With the valve covers removed, obviously I can see the cam followers move up and down. One of the exhaust cam followers spins as it moves up and down. None of the others seem to do that.

At one point in the testing, in an attempt to hear the leaks better, I applied 40 psi of shop air directly to Cylinder 3. I had my socket and breaker bar on the crank nut, and when I moved it back and forth trying to slightly open and close the valves, the cylinder must have sealed and forced the piston down, and it jerked the breaker bar about a 1/4 turn. When I went to move the bar back, it jerked it the other way. Not sure if this could have done any damage.

At one point in the testing, I noticed that as I rotated the crankshaft, the right side camshaft seemed to get hung up temporarily, then sort of pop free. Pop may be an overstatement of the noise/phenomenon, but it stopped briefly, then broke free. I didn't see any obvious place it was getting hung up. It happened at the point just before the exhaust valves at Cylinder 1 opened. I don't think this was happening when I started testing, so I'm wondering if my 40 psi breaker bar experiment may have caused this.

Thanks for listening. I'm all ears, and very anxious for any help you can provide. I'd really like to be driving this car.
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Old 06-12-2014, 06:09 AM   #10
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I fixed it!

So here's the update, for those who are curious, or to help those in the future, if they happen to have a similar issue.

After compression testing, leak down testing, and visual inspection, I made my diagnosis. There were obvious signs that the last mechanic who worked on this car was sloppy, if not incompetent. Screws were missing from the front bumper and the coil pack wire harnesses, the belly pan was missing, and two of the four plastic engine covers were missing. Also, I noticed white paint marks on the camshaft pulleys. With this information, and knowing how important it is to use the cam lock tool, my diagnosis was that the mechanic who replaced the exhaust camshaft in January 2013 didn't use the camshaft locking tool, and that the timing was slightly off. I pulled the trigger and ordered a camshaft lock tool off of eBay (approx $120 shipped). The tool arrived, and it was time to see if I had guessed right.

The tool went on to the left side fine, but it wouldn't go on to the right side. It went on to the exhaust camshaft, but wouldn't go on to the intake camshaft. It looks like I was right! Time to get the timing belt off.

So I basically did a timing belt service, but had to disassemble the right side without the lock tool on. As soon as I loosened the cam pulley bolts, I rotated the intake camshaft and got the tool to engage. Then I put everything back together. Also cleaned up a lot of oil on the front of the engine. My guess is that the hack mechanic didn't replace the cam pulley seals - but I did.

Moment of truth - time to start the engine. It takes a couple of turns to get fuel back into the engine, but then starts right up. After a few seconds, my wife, who wanted to watch the start up to see if the engine would explode, tells me she thinks the car is on fire. Smoke is coming out from under and behind the car. After initially being startled by the smoke, I realized that I had put oil into some of the cylinders when I was doing testing. I assured her that the car was not on fire, and that the smoke would only be temporary as the oil burned off.

I let the car idle for about 10-15 minutes, then took it for a drive. While not perfectly smooth (I assumed because the computer still needed to fine-tune the timing), it ran well. No CEL.

So now it's five days later. The car runs great! I've been driving it every day, and it's a dream. I was really looking forward to driving this car, and was getting frustrated watching it sit in my driveway while I decided where to spend my time and money troubleshooting it.

Total cost of the repair was about $200, most of which was the cam lock lock tool. Now that it's running well, time for basic maintenance and new RS6 replica wheels!

Thanks to all who gave advice.
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Old 06-12-2014, 06:09 AM
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