Here's the deal. I just bought this car yesterday knowing it had a CEL. It's a 2001 a4 quattro 2.8. The previous owner told me it needed a cam sensor before I showed up, so I brought my scanner with me, and confirmed that it indeed was throwing a p1392 code. It was also showing a major evap leak. I did the typical gas cap check, etc. I found that the big vacuum line that runs across the front of the motor was split in several places, and taped back together. No big deal, I've already got one ordered, should be here Wednesday. I'm also going to replace the rest of the lines with the silicone ones that everyone here seems to recommend. I ordered 20ft to make sure I had enough, and extra in case I screw it up, or need more in the future.

Back on topic. The car idled a little rough, and felt like it was lacking some power. The only thing I have to compare it to, is my cousin's 01 s4, which there IS no comparison. That car is insanely fun to drive. Anyways, after I got it home, I started digging through the piles of receipts that he gave me, and noticed that a shop had JUST done a timing belt, water pump, and brakes on it. The invoice was dated August 13th. I bought the car August 14th (Yesterday). Scariest part about it, was it was Discount Auto and Tire (yes, THAT Discount Tire).

I did some more research on the p1392 code, and noticed that the most common cause for this code, was an incorrectly installed timing belt.

Do you guys think it's worth buying a cam sensor to see if it does indeed need one? Or see if the old owner will work with me and get the shop that did the work to fix it? I know it's a pretty easy job to change the sensor, but forking out the 160 bucks that the audi dealership wants for the sensor doesn't sound like a novel idea "just to see" if it will work.

 

You can buy a cam sensor from a parts car for about $20 and change it yourself. That code is a cam sensor that has hard-failed - open or shorted. It's possible that the belt is on wrong but you'd definitely know it. These engines are very smooth and being off a tooth would make it run noticeably worse.

The sensor being called out - bank 2 - means it's on the driver side. It's on the back of the head so it'll be a little tougher than the passenger bank sensor, which is on the front. It's held on by two 10mm bolts and has a harness plugged into it. If you move the coolant tank and solenoid panel on top of the rear of the engine it should be accessible if you work delicately. It'll probably take you 20-30 minutes to do it.

Trust me (and all the others you'll see on here) when we say owning an Audi is much easier if you work on it yourself. These cars aren't very hard to work on and there are hundreds of DIYs, not to mention many very experienced owners here who can and will help you. If you plan to pay shops for all your repairs, you're going to pay a fortune.

I'd pick up a part-out cam sensor and swap it to see if that's a fix before ripping the front of the car off based on Internet research. Cam sensors aren't the most common failure by any means but they do happen and it sounds like you're dealing with one.

 

I had all the covers off the motor today, and was able to get to both of the bolts on the drivers side cam sensor. If anyone local to Temecula, CA has a take off cam sensor that I can buy from them, I'll come get the damn thing tonight... lol. It idles pretty rough, and has a hesitation when accelerating. It runs better when it's cold. I don't plan on paying anyone to do work to the car, since my brother runs a very large shop in North San Diego County. I won't say the name, since I'm sure there are sponsors on here that pay good money to advertise. I know how it is, I sponsor an ATV forum with over 20,000 members.

My only question was are the odds good that the shop that the previous owner had work on the car, screwed up the timing belt installation, and the cam sensor is still in fact good? I read the DIY on testing the sensor, but wanted a little input before I went and pulled off the old sensor, and had to go buy a decent multimeter.

 

It's possible that they could've messed up the belt job, for sure. My reasoning behind doing the sensor first is that it's cheap and much less labor-intensive than redoing timing. Very good that you have access to a shop - it'll make your work much easier. Maybe try this - swap your driver and passenger cam sensors, clear the code, and fire it up. See if the code changes to indicate a bank 1 failure, which would prove the sensor bad. If it comes back the same, I'd start thinking about the timing being off.

 

Alright, just an update. I was wrong about the code, it was p0340, meaning Bank #1. I bought a new sensor today, and put it on, and still threw the code. Something strange happened, though. Today, before putting the new sensor on, I scanned it, and got misfire codes on #1, #2, and #3. Replaced the sensor, drove it, and it FELT like it had a ton more power up top, but still threw the p0340 code. No more misfire codes.

I'm stumped. I read on another forum while googling the problem, and someone said something about the one of the cam sprockets jumping a tooth? Wouldn't it barely run if that were the case?

 

Bumpski, Anyone?

 

That's possible but it still seems to me that being off a tooth, you'd feel a decent difference in the way the car runs, particularly at lower RPM operation. Does the car feel like always?

 

Re-read your first post. If the cam sensor code comes back with a new sensor on it, it's your timing. The shop screwed it up and it's off a tooth on the bank 1 sprocket. It's easy to have that happen once you apply tension to the new belt. You almost have to set it up off a tooth so it drops into place. I doubt it jumped a tooth - I think it was off when they assembled it. Take it to them, with the prior owner who paid for the work, and make them redo it at their expense. They screwed it up.

 

That's the answer I was looking for. I was just getting frustrated, because the previous owner told me "Well, I drove it the day we picked it up, and it felt fine."... Guy was kinda douchey though... if that's a word. The work, according to the invoice, was done at a Discount Tire... I didn't even know discount did timing belts; ESPECIALLY on an Audi. I'm not getting much of a response from the seller at this point, so it looks like I'm going to have to get pushy.

 

Another update.

I just got a call from the shop that was supposed to be re-doing the timing belt, and he informed me that the guides on the cam chain tensioner inside the head, are broken, causing there to be slack in the chain thus throwing the timing off.

Sound like it makes sense? He said the tensioner still works, moves in and out, but the pads are either gone, or broken. He's kind of hard to understand due to his very thick accent.