Pmulls870

Also, is there someone that sells used 2.8l 30 valve blocks? Or block and build kits? At 200,000 I'm thinking it might be easier just to rebuild on a stand and swap Out the engines?

mrk1327

Prospeeder knows Audi as well as anyone so his advice is sold. As far as a complete engine rebuild or swap if the compression check on all cylinders is strong I wouldn't...Imho...I do know a guy with very very reasonable used parts in Pa.

Pmulls870

Lol I come from the diesel world, for us its cheaper to build on stands and swap motors in and out. I'll get used to this eventually . How about a vacuum leak?

Prospeeder

Lean codes are telling you the engine has richend up the mixture to an extent not normal trying to compensate for the lean condition. Which is usually an air leak, like breather pipes from the valve covers, or at the throttle body, all the vacuum lines running around the top of the throttle body area, suction jet pump, pcv breather, the vacuum line running over the drivers valve cover area on top the the chain tensioner down to the vacuum reservoir in the fender area.

The mixture of fuel and air must be just right, so unmetered air entering the air stream ahead of the mass airflow sensor is not compensated for and the engine then has too much air, not enough fuel, so its lean. The engine management tries to richen the mixture as it sees, running the fuel trim numbers up and up until it cannot add any more fuel.

Pmulls870

I started pulling hoses and testing last night, I would say I'm about half done. This engine needed to be gone through and cleaned anyway. So far no BIG leaks. I found a few that looked worn and tested them with compressed air, they were failing at around 18 PSI. The hoses that still look good are failing at around 60PSI. The new hose Won't break with the compressor so I am guessing these vacuum hoses all have a useful life and mine are all at the end of it. I went with different colors for different hose sizes too so it looks kind cool in there now.

Pmulls870

I went through all of the visible hoses and it didn't seem to fix the issue. I am curious what the spec #'s are for ahort and long term fuel trim percentages? I was driving around a bunch today trying to catch live data recording during a misfire, so far no luck and at -13*F, I don't want to play with it too much. Given that the car won't misfire until it is warm, it gets WAY worse thr colder it gets, cylinders 5 and 6 misfire, I get bank 2 and 1 lean codes, and I can watch the throttle go down and down and down and then it bounces around misfiring does anyone have any other guesses of obvious things I might be missing?

Prospeeder

Fuel trim will max out at +-25, normal is for it to float between about +-8

Pmulls870

I ran a bunch of data tracking this weekend and finally caught the elusive misfire and the fuel trim issue during the testing. I will be analyzing the data and will post when complete. Given my issues, are there any particular comparison curves you would like to see?

Pmulls870

While running my tests I a m running into some questions. Bank 1 short term fuel trim sensor 2 is reading n/a and bank 2 short term Fuel trim sensor 2 reads 99.2 constant. Bank 1 short term sensor 1 reads +-8 as does bank 2 short term sensor 2. These are displayed as % on my unit. Should these be displayed as a %? My O2 sensors all read around -.5 I think that is normal. Can anyone tell me if this is normal?

Prospeeder

yes they are in percent. You are only concern on Bank 1 and bank 2 sensor 1. Sensor 2 is for catalytic converter monitoring and is useless data for you.