1998 Audi A4 2.8 quattro. AHA. I have been getting a misfire on bank 1 on all 3 cylinders since i have owned the car. It would be easier to state what i haven''t done to rid this issue and that is rebuild the cylinder head and a total timing belt replacement.

I only get the misfire at idle.

i checked Block 093. Bank 1 is 29.0kw and bank 2 is -7.0kw. Idle stabile is 4.0kw on bank 1 and Bank 2 0.0kw. I have not pulled any timing related codes since owning the car. I have checked the timing marks and everything lines up. I have read there is supposed to be 14-16 rollers in between. I followed what Bentley said and that's 16 rollers. Everything lines up.

is this a sympton of a failed timing belt tensioner?

I am stumped. any help would be greatly appreciated.

 

Have you checked compression? How about swapping injectors side to side? Or the O2 sensors. Something is different between the banks, obviously.

 

I have not done a compression test but i have swapped everything. i think its mechanical. it has been consistent since i have owned the car. all parts that have been replaced or thought to be bad has not made any difference.

 

It's not a timing belt issue if your marks all line up and the chain has 15 links between marks on the CCT. It actually would help if you listed what you've done so people don't suggest things you've changed. I'll start though - to throw an idea out there, it could be a failing cam sensor. Swap them between the two banks, clear codes, and see if the misfires move to the other bank. What's the condition of your plugs? Any recent maintenance shortly before the issue came up? Are you dealing with other side effects like sluggish acceleration, worse fuel economy?

 

I noticed that you don't mention that the exhaust cams are timed correctly to the crank. See, you could have perfect timing between exhaust and intake cams, but both would be wrong in relation to crankshaft position. Did you use the cam-lock bar and crank-lock pin to set the cam timing?

 

I had the same issue and ended up having to replace a bent cam tensioner and ultimately the camshaft as well. Diagnose the cam position sensors and check the cams sprocket for broken teeth. You must have already checked the plugs, wires and coil pack. But thes a voice in the back of my mind saying "What if the computer wasnt telling that bank to fire at idle?" and to me that suggests an intake issue. But it would likely be in the manifold on that side of the engine. Just throwing thoughts out there. Like i said, in my experience, i had to replace that side of the cam system. If youre doing the passenger side (I dont know which bank is which), you might as well do the timing belt and water pump as well. It will save you work in the future.

 

Imthedevil- yes I have had sluggish acceleration and bad fuel economy since day 1. I have replaced both cam sensors with working OEM replacements. The list is to vast. plugs are good. I have replaced and switched between everything that can be done aside from timing belt and rebuilt heads. I have replaced all the seals intake, throttle body, coolant sensor, air ducting, vacuum lines, solenoids, suction pump, check valves, oil pressure check valves under the intake manifold, injectors, fuel rail, leak detection pump, evap system, SAI, radiator, transmission fluid pump, fuel pressure regulator, ECU, TCM, plus various clamps and hoses that were missing or crackedl, pcv valve, I have tried new and used o2 sensors both banks pre and post. Pre cat O2 on both sides get the code. Bank 1 starts out at around -1 -2% then after warm up stays maxed at -25% bank 2 reads was I assume is correct for the most part it stays around 0 +- a %. The last time I changed them out I now get a code relating to electrical malfunction code but the internet has no info on this code. It's the only code for the O2 sensor with no info. I took out the cam tensioner on bank 1 cleaned it up all looked well put it all back together ran the same. I do get the 3 beeps and the oil light. I have replaced the pressure sensor and dropped the pan checked the oil pump for sludge etc... and checked the chain and tensioner all looked and felt good. So as you can see I am at a lose.

 

turbo510- I have not checked that timing I was hoping to do that this weekend. I will post an update if I can find the time. Bank 1 all 3 cylinder is a constant misfire at idle. horrible acceleration and worse fuel economy.

 

Sivgote- I have replaced the ECU I thought there may be an issue with that but didn't make a difference. I had a recent moved that put my project on hold. I was working on rebuilding 2 heads to just replace all of that in 1 go. I feel like at this point it is a mechanical timing issue or a short in the harness somewhere but I have not found a short yet. I have Ohmed and Volt tested most of the important connections and all are in tolerance.

 

I have swapped all that can be swapped and the issue does not follow the part. everything remains on bank 1 same readings same behavior. at this point it is either a short that I haven't found yet or simply mechanical in cylinder 1.

I now have a code for an electrical malfunction for O2 sensors bank 1 and 2 pre cat position. I bought new oem bosch sensors replaced the old ones then this codes came up. I have unplugged them and unhooked the battery to reset the system still get codes. I have 3 sets of pre cat o2 sensors they all show the same code.