nrlarson0107

I would like to start by thanking everyone for the information I have already read. this is an awesome forum!

Here is my issue. Over the weekend I bought my first Audi. Or as my two year old son say "Owie car". It's a 1999 A8. (pre facelift) The story behind the car is the guy I bought it from purchased the car two years ago as a project car. It had been hit in the rear. After two years collecting all the parts he decides to sell it. He starts the car and after sitting for multiple years it now runs like crap. When I ran the codes it had nine codes. One random/multiple misfires and the other eight were for misfire on each cylinder.

I have drained all the gas put a can of seafoam and 6 gallons of gas in. Also I replaced the spark plugs. I have run it for 15 - 20 minutes and it still runs like crap.

Also while running it for awhile the pass side cat started smoking and the drivers side cat started to glow red hot.

Any good ideas on what the issue could be? It hasn't thrown any other code. Just the misfire codes. (it's down to only showing misfire on 4 cylinders #1,6,7,2)

Please help! Thanks guys. Can't wait to hit the road!

albundy3670

Hello and welcome! I can share with you my knowledge of what has worked for me working on the A8's. I let one of my A8's sit for about 9 months and when I started it back up, like you, the car ran like crap. I added fuel and a bottle of Techron fuel injector cleaner ( $6 at Walmart ). That helped. I also had to remove the fuel rail to replace a breather hose on the intake manifiold, so while the fuel rail was off the fuel injectors got a soaking in fuel injector cleaner for a few minutes, that helped more. That got the car to a smooth idle.
My passenger side exhaust was smoking too. It was a leaking valve cover gasket. When I would turn off the car and could hear a drip on the exhaust!
As for the misfire codes, I have gotten them on rough start-ups before and they have not come back.
I don't have anything on the glowing drivers side cat converter, although that should be corrected. Mine were replaced when it sounded like there were marbles in them!
6 gallons of fuel gets us to about 1/4 tank, my advice would be to put in more fuel and a bottle of techron. Hopefully that will get the car to a better start! You are at the right place, all the answers are here in the forum! Best of luck with thge car! P.S. Try the simple inexpensive fixes first, the cars get expensive quick!

silverd2

Agree with the Techron...in particular...no substitute...it's the best AND different from others.
You may also have to remove injectors for a cleaning, after years to gum up...or at the very least, pull em to check spray patterns.

nrlarson0107

Thanks for the advice! Am I ok with mixing the seafoam and techron? I will also put in more fuel. I think I figured out the glowing cat. From doing a little interlink research it sounds like some of the unburnt fuel is getting caught in the cat and burning off there. I know that cat is shot and needs to be replaced. (anyone have one to get rid of? stealer wants $625!)

I will also pull the fuel rail and try some injector cleaner. I'll give an update after.

Thanks again for the advise guys!

nrlarson0107

Injector cleaner didn't work. Now after more research I'm thinking maybe a cam sensor or cam adjustor. Is there anyway to know if they are bad? I'm missing on both sides. I find it hard to believe they would both go bad, at the same time. But who knows...

I should have a vag-com scanner in the next day or so. Will that give more insight than just "misfire detected"?

silverd2

Cam position sensor should throw a separate code that even a basic code reader would detect...plus a CEL. Bad cam adjuster should throw a timing code, also readable and a CEL tripper. But cam adjuster alone shouldn't cause misfiring...a cam position sensor could, but really should show it's own failure code.
Keep us posted on what ya find.

nrlarson0107

I got my vag-com today. Plugged it in tonight and here are the codes I got.

14 Faults Found:
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16685 - Cylinder 1: Misfire Detected
P0301 - 35-10 - - - Intermittent
16691 - Cylinder 7: Misfire Detected
P0307 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent
16688 - Cylinder 4: Misfire Detected
P0304 - 35-10 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16685 - Cylinder 1: Misfire Detected
P0301 - 35-10 - - - Intermittent
16691 - Cylinder 7: Misfire Detected
P0307 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent
16690 - Cylinder 6: Misfire Detected
P0306 - 35-10 - - - Intermittent
16516 - Oxygen (Lambda) Sensor B1 S1: Signal too High
P0132 - 35-00 - -
16536 - Oxygen (Lambda) Sensor B2 S1: Signal too High
P0152 - 35-00 - -
16500 - Engine Coolant Temp. Sensor (G62): Implausible Signal
P0116 - 35-00 - -

Never any code on the cam sensors. Thank goodness! Any thoughts after seeing the codes? The low power came from me leaving the car on for an hour to reset the radio. I forgot I left it on.

Also i had issues with the cowl drains clogging and the cowl filling with water. I pulled the ECU and TCU and both looked dry. didn't see any water in the box.

Ugh! I need to get this figured out! Let me know if you get any other ideas! Thanks again for all the help!

audinutt

Start by changing the ECT (Engine coolant temp sensor) This could make it run super rich and cause misfires, glowing cats, etc...

TerminA8r

Test your ignition control module.
http://forums.quattroworld.com/a8/msgs/39166.phtml

nrlarson0107

I'm guessing the ignition module is the issue. I went to pull the cover back and noticed the Phillips screw was rusted and slightly stripped and the cover was broken. After i moved it out of the way I noticed the bolt securing the modules was also pretty rusty. Also the pins were pretty corroded. I was only able to test the top one. Three tested within spec, the other was low. I found out there is an A8 at a salvage yard about 45mins from me. I need to head that way to get some parts for another project. So, I'm going to swing in and test the modules on that car. If they test good I will pick them up. (If the price is right)

Will give an update tonight.