i have this post on another forum but i figured i would branch out so ill try to sum up what we have found already

Ok I got a 02 a6 with a 3.0 v6. Needed a motor. Had a cam gear eat into the head. I got a motor off eBay. Guys said it ran perfect he drove it into the shop to pull the motor when I bought it. I put the motor in and started in up. It ran like crap. I pulled the codes. P0391, p0366, p0346, p0341 and a random misfire code. All 4 camshaft position sensor range codes, I tested the sensors and even replaced 2 of them off the old motor. Tested the engine speed crankshaft sensor. New plugs swapped the coils with other motors, when i turn it over it cranks and locks up for a quick second and continues to turn over, every once and a while I'll get a backfire, then after 6-7 times of cranking and feathering the throttle it fires up. Revs up and the dies. Start, rev, die. If I give it slight throttle at about 2000 rpms it will smooth out and run. But I get a slight rattle sound like a diesel chatter. I was listening around the motor to see if I can pinpoint it and I saw the cat was glowing red hot. After like 1 minute of running. We shut it off. I figured cat was clogged. Lowered motor and pulled cat. Blew air through it, it had good flow. Reassembled everything, put new plugs in, fired it up. And this time it actually ran but it ran rough but it was surging really bad, up and down up and down up and then dies. Figured I had a vacuum leak. I checked everywhere and couldn't track one down. I unplugged every line and capped it, with no results. I figured it time to bite the bullet and check timing. I pulled the covers. And the driver side cove had a crack in it. When I pulled it off the very thin lip on the driver side exhaust cam gear was bent in and it would bearly touch the intake gear. I'm thinking when it got hit maybe it locked the two gears together enough to jump 1 tooth. If I jumped 1 tooth on the exh cam would it cause all my symptoms? I don't have the cam lock tool. And I have called every shop in Knoxville and no one has this style. Only 2 euro shops and I can't borrow it. They will only do the whole belt job. So I have to pay a couple grand to let them line my cams up. Boo. Anyone got any other ideas. It's hard for me to believe it's the timing when the guy I got it from swore it ran fine and even offered me a replacement. (if he's even serious) I'm out of money and out of options. I have google myself into insanity trying to figure this one out. What could it be?

i have now put a new timing belt on and redid the timing twice. it is dead on perfect. every step for the timing was done properly.

I pulled the fuel rail and all the injectors and swapped them with the rail and injectors from the other motor. No change. I unplugged the maf an no change to the surge. I unplugged the lil valve next to the air box with a wire plug and two air lines. No change. I've checked for air leaks. What about the egr system could a leak in it cause this? Why would it throw cam codes

ok. i just redid the timing again. it took me a while to find that socket. this time i locked the crank, locked the cams, lossened the cam bolts.took the socket and turned it all the way clockwise till it stopped. then the other side. released the belt tension and checked the adjustment with the socket again. tightened all cam bolts. released the cam locks, released the crank lock bolt. put eveything back together. fired it up, reved up and ran smooth for a second or two then started surging again. pulled the codes. all four cam positioning sensor range codes and a random misfire. the timing is dead on perfect. it runs so smooth at the top of the surge and at the bottom of the surge. i give up.what is wrong with this thing.

do all the cps wires run independently to the ecu. or do they run together anywhere in the harness. what r the odds of me having a bad break in my harness. i have 5v and good ground going to each sensor.i was ohming out some wires. and at the crank position sensor. the blue wire wasnt getting any connection through the plug. so i cut off that plug from the other wire harness. and soldered in on. re tested that wire and it was getting good connection. cleared the codes. started it up. and it still surged but instead of instantly throwing the codes. it actually took about 15 sec. but then it still threw the 4 cps codes again. prolly irelivant but i figuered ide throw that out there. if my crank position sensor was goin bad would it throw the cps codes? i can unplug the crank or engine speed sensor and it wont start and gives me a engine speed sensor code. so i think its working fine. but the car does take forever to start. after it runs for a few cycles it starts pretty easy. not right up but u only gotta crank it for about 5 secs at that point.

i just checked the wiring and ohmed the signal wires from the sensors to the ecu. and they ohmed out ok. so there isnt a break in the wire.

 

When you had the valve covers off did you inspect the cam chain tensioners? I believe this car has hydraulic tensioners on both sides which consists of a reddish plastic (phenolic?) guide which is pushed up by hydraulic pressure to tension the chain connecting the input and output camshafts. The tensioner guides and tensioners are a weak point.

By the way, your red hot cat was caused by unburnt fuel getting into the cats. This could be cause by bad valve timing or failed coils or miswired plugs. Are you sure that in the process of changing the engine that you got all of the ignition wires installed correctly?

 

This motor doesn't have the chains. It's cams are ran directly if the belt. And I don't have wires I have the individual coils on each plug

 

Sound like the ECU needs to be reset or in less you also swapped the ECU too.

But first is the engine the same code? If not, don't know what to say.

Well your ECU needs to relearn the engine and also TCM too.

Well good luck with that.

 

how do i go about getting the reflash done? does the dealership do that. or can any euro shop that works on audis alot do it? does the computer need to be in the car to do it, or can i just send the computer to them.

 

This is using a ross tech VCDS/VAG COM Cable.

how do you reset ecu using VAG? - AudiWorld Forums

Read post #8
http://forums.vwvortex.com/showthrea...-reset-the-ECU

 

heloo im having the exact same problem with my car .. i was wodering if you got anywhere with yours ??? im out of ideeas and desperate for some help .... thanks a lot