All,
First off i'd like to say thank you to everyone who participates in these forums. Threads here have helped me keep my Audi's running smoothly and have saved me money since I bought my first Audi in 2014. A big thank you!
Currently I am at a loss trying to figure out what's wrong with my car, so i'm coming to you guys for some advice, pointers, whatever you have to offer. I'm having a strange issue and it's a bit hard to explain, so I've also made some videos. Hopefully I can post them here.
Car Data:
I have a 2007 Audi A4 Avant 2.0 Turbo / 6 Speed Manual S-line. The car has JHM Stage 3 tuning and the TD05HR turbo. It also has an ignition interlock system installed.
Brief History:
Purchased Car in May of last year. installed interlock. Blew Up original Motor in June. Car was previously beat on pretty good (taken to track, etc), so I chalked the failure up to me finishing her off with my lead foot. I Purchaseda used repalcement motor from LKQ and had a reputable Audi/VW shop install the engine. - all good
Fast forward to October and that motor goes south. I was told by the Audi shop that rocker arm failure caused a valve to drop and ruin the engine.
Purchased another used motor from Ebay. had same shop install this motor. Shop calls me up and reports they are having an intermittent misfire isolated to cylinder 4 under heavy load. They do their thing trying to troubleshoot the issue:
swapping coil packs and spark plugs.
Tried new set of injectors (has S3 injectors for tune)
Testing the Wiring Harness (which came back good).
Re-flashing my computer, and also trying a new computer.
Compression test all cylinders, all over 180.
They finally call me up and tell me that they have done their best, but cannot figure out why there is a misfire. They said their next course of action would be to dig into the motor, and that it seemed to be something mechanical. It being an Ebay motor, i'm thinking I guess that's possible. I start looking down the RMA route. After consideration, (basically out of cash) I backed out of the RMA route and picked up the car. I figure at least the car runs and I can drive it to work and back and just stay out of boost, and possibly even fix myself.
Problem:
It's worth noting here that my car was idling for about 30 minutes before I took off. I was paying the bill, talking to the guys about my issue, etc. I then start my 20mi drive home with the car. While getting on the freeway I get into a bit of boost and feel the misfiring (which i expected based on the statement by the shop), so I keep out of it and try to keep it under ~3k RPM. There's lots of traffic so it's pretty easy to do. What happened next is what I did not expect. About halfway home while stopped in traffic and car idling, the car nearly dies. The tach drops to nearly 0, then immediately spike back up to 1.2K. then settle back down to ~800. The car continues to surge and buck while trying to stay running. it starts off mild, but seems to get worse and worse until it's barely driveable. I was able to baby her into my driveway, but barely.
So I leave her idling in the driveway for a couple minutes while it seems like the computer is trying to sustain the engine running. The engine finally dies, and i restart, but it dies. OK, push it up into my garage and get a code reader on it. At this time I could not for the life of me get VCDS to connect to my car. I also cannot get Torque connected to my cheap OBD2 reader. Also the car won't start now, just turns over.
Pulled off the coils, pulled out the plugs and I do a compression test on 4. Plugs all look great, and compression test looks good to me, a few cranks and it's over 180.
Anyway, I let the car sit for a few hours, plug everything back in and start her up. Starts up fine. I go for a test drive, pulls hard, drives fine. At this point no misfires, seems fixed.
Upon driving further, car begins to have misfires again.
I pull back into my driveway and this time I get VCDS connected. I pull the following faults:
P0300
P0303
P0304
P0353
P0354
Based on those I purchase a set of new coil packs.
Installed coil packs and for the heck of it I swap in a cam position sensor from one of my blown up motors, thinking maybe it's related to that.
the next test drive is interesting. The car seems fine and fixed again, however I notice now she's pulling less boost, seems to peg at 10 PSI and not ~20PSI (where the JHM Stage 3 Tune calls for). At this point i'm like whatever, i'll deal with it, at least it works. I drove the car up and down the freeway for about 30 minutes, driving hard and normal. Absolutely no misfires whatsoever. I return home and park it. Deemed it fixed (again).
About an hour later i'm ready to test her again and see if she's truly fixed. Start her up and we're back in misfire city. Car won't stay running. Won't restart. Stuck around the block from my house, pushed her back.
Now I notice that when the car is surging up and down there's some strange things happening:
1. With key on and engine not running, I hear the fuel pump kick on and off, over and over. (Just as if you were to turn the key off and on a million times over and over)
2. I also hear the manifold actuator thingy going nuts, switching back and forth over and over very fast. (Again, as if someone is switching the key off and on very fast)
3. Runs for less and less time and more roughly each time it gets restarted.
4. Intermittant connection to ECU (either via VCDS or Torque)
5. Gauge Cluster temp sensor intermittently reads and doesn't read. (When reads cold, (needle all the way left) and I know car is warm, the car will not start at all) *Noticed that check engine and EPC light flash when the gauge goes south also. Then fan kicks on.
And then when the car will not start at all, these things are happening:
1. Fan is running at full blast / Whether car is warmed up or been sitting for a couple hours and is cool to the touch.
2. I cannot start the car for some time when it gets into this "state". 3-4 hours?
3. Cannot connect to the ECU (via VCDS or torque)
At this point it seems to me like a computer issue, but shop is adamant that they have tried a new computer, and that's not it. They also say the wiring harness has been tested with less than 1/10v loss, and so it's surely good.
I am also no longer getting any engine fault codes.
The next day my buddy and I are testing the coolant temp sensor (based on fan going full bore), when another buddy who is more familiar with JHM tuning stops by. We connected VCDS and he notices the car is in fact back to stock firmware. ??? How the hell? He eventually gets it back to my JHM Stage 3 tune, but he's confused and i'm really confused.
Misfires are back under heavy load, but only after 20 or so minutes of driving. Further driving causes car not to idle, further restarts lead it not to start.
This seeming like an ignition issue, I made an appointment with the interlock folks to have their wiring checked. I had them do their tests this morning, and everything came back good on their end. They also explained to me that they "T" into 3 wires. Ground, ignition, and starter. All connections look good.
Videos trying to describe issue:
ECU Connection Issue after Warm - https://www.dropbox.com/s/4f86qopz39...20Wam.MOV?dl=0
Manifold Actuator Going Nuts when key is on - https://www.dropbox.com/s/z2ayuf4t0m...%20on.MOV?dl=0
Sorry for the super long winded explanation, but wanted to make sure I could get as much info in here as possible. I will follow up with the results from the full scan as well, just don't have that data handy atm.
Please let me know what you think, of if there's any further information I can provide.
Thanks,
Kyle
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Originally Posted by Kyodesle
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