GreenBucket

I had a problem with my car (97 A6 Sedan) haveing no power and studering under acceleration froma dead cold start. It would fade away after about 30 seconds or so and then be fine.

I was digging thrue old paperwork and found these codes

16554- Fuel trim malfunction bank 1 A
16555- Fuel trim system lean bank 1 b
16558- Fuel trim system lean bank 2 b
16824- Evaporative Emmissions Control System EVAP purge malfunction b

Now I don't think they were fixed becuase I had the car scanned today and there were 9 codes, and my mechanic didn't right them down but he said they were all fuel trim codes being bank 1, one was about running lean, and about multiple misfires to acouple cylinders and about a bank 1 02 sensor being bad. He just cleared them and said maybey it was fixed and never cleared out completely so rather than do any work yet he said if the light was to come back on just bring it back and then we will see what it says again. So I would like if someone could basicly just explain to me what all those codes mean out of mechanics term please and what to start looking for.

austinado16

Bad spray pattern from the fuel injector(s) will trigger the "lean" and "misfire" codes. Running it low, or out of fuel will result in the same codes.

The fact that the car runs poorly/accelerates poorly cold tells me that you don't have an oxygen sensor problem because when the engine is cold the oxygen sensors are not part of the fuel management process.

What your symptom tells me is that you have bad injector spray pattern and probably a ton of carbon and similar goop built up in the intake track and on the backs of the intake valves. The cr@p acts like a sponge for fuel. So cold, when you need an enriched fuel mixture, the sponge is soaking up all that extra fuel and the engine is therefore starved and running lean. The other thing that's happening at the same time, is the injectors are spraying in pee streams instead of a nice fog pattern. This makes things worse, especially cold, because the fuel isn't being atomized nicely, it's being soaked up easier by the carbon, and your lean situation becomes worse.

Here's what I'd do if it was mine:
1) Buy the BG Induction Service 3 can kit off ebay and do an induction service using all 3 cans (one cleans the throttle body, one in the gas tank and one you run the engine on....let cool 15min.....then go drive it.

2) If this doesn't completely cure the problem, pop all of the injectors off (15min job) and spray them out inside with carb cleaner (from the back side) and then tap them out onto a hard surface, spray out again, tap out again, and reinstall. This should bring them back to life.

3) Prior to installing the cleaned fuel injectors into the cylinder heads, leave them mounted in the fuel rail, put down some paper under where they will be spraying (so you can see a print of their spray pattern) and crank the engine over long enough to get a good spray out of them. Re-clean....or replace, any that don't spray like the rest.

This should get you back on the road nicely. If you want to get a little more in depth after this, you can pull the intake manifold, seperate the halves and physically clean it by hand (a soda blaster would be fast and easiest)

Then erase the codes, drive it, recheck the codes and see if you need to dig in further. You may ultimately need to replace both oxygen sensors......but not yet. Cure the cold running problem first and then pursue what it does when hot.

Make sense?

GreenBucket

Ok I will try this, Thanks for all the help.