Can this vac line cause bank 1 Lean?
 

http://img530.imageshack.us/img530/5...escolorgn6.jpg

I have been getting have been getting a Bank 1 Lean code since 100 miles or so after seafoaming my car (01 1.8TQ tip) in June. I thought it might be something as simple as a vac line leak and so i have already replaced the three vac lines shown in red and added a boost gauge. While replacing the line going to the DV i took the time to replace the stock DV with a 710N until i figure out my chipping plans. while trying to reconnect that line under the manifold i noticed the green line and was curious where it goes. i pinched it and it feels brittle and dried out. Could this green line be causing a vacuum leak and could this cause a lean code on Bank 1? I'm really hoping that it's not the MAF...

how about indicate north... otherwise its not really a map, more of a drawing.

10 points if you know what im talking about^^

schematics are cool but its helpful to post what those numbers correspond to, im not going to take the time and squint at my computer screen to figure out what everything is. also vac lines, unless completely disconnected, wont throw a lean code when just slightly cracked. it takes a large leak (or a bad maf :P) to actualy throw a code.

The picture is oriented as if you were looking at the engine from the front of the car. I found the Diagram from another Vac line thread so i dont know what the numbers correspond to. the lines themself are not numbered though so i had hoped someone with knowledge about their engine may know what eveything is and its purpose.. it my understanding that the greem line has something to do with a secondary air something?

Probably the maf, but if you got this code imediately after seafoaming, your 02 sensor may have gotten fouled. Try taking it out and clean with an electrical parts cleaner. I don't know if id use brake parts or carb cleaner on it. That vaccum schematic is for a DBW engine so it won't mean much to most people. Instead of guessing or wondering, it would be best to just replace all the vac lines as good measure. But like I said, I bet your maf is shot. If you have anywhere near 100k on the stock maf then it's highly likely.

Im at 85k miles and as far as i know the O2 sensor is fine. i took it out and it looks fine. wouldn't the O2 sensor throw its own separate code? and for some reason after clearing the lean code the engine will stumble a little the next time i start it. I shut of the engine and start once or twice more until its smooth and then its fine and gets full boost while driving.

Same as you're having here?
After you clear codes, the engine goes through an adaptation process which might explain the stumble. If replacing all the vac lines and if all your check valves arent rotted out, and you still have the problem, replace your maf.

I guess that's becoming my only option... Thanks for the help

you cant look at your O2 sensor and tell if its bad, just like you cant look at a car and tell how much gas is in the tank. O2 sensors will slowly get less and less accurate with age. if its telling your engine the exhaust gas has too much fuel in it (too rich), for example, if because its encrusted with carbon deposits which is reads as fuel then the ECU gives the engine less fuel to compensate. and then you run lean.

my car is having a similar problem right now. in the higher rpm range im getting a knock sensor reading that is putting my car in soft limp mode. i have a innovative motorsport wide band air/fuel gauge that needs to be recalibrated to the open air levels of O2 (by taking the sensor out of the exhaust pipe, havnt had time to do it yet). it probably needs this recalibration about now because im running a little lean, which explains the knock. if that doesnt work, il up the fuel injection a little bit.

so if your still on your origional O2 sensors, it couldnt hurt to replace atleast the first one. thats the one that matters. the after cat sensor is just to measure the efficiency of the cat, which isnt really important to performance.

In the other similar thread, Mike@DTH had recommended testing block 032. ive done this but cant figure out lean or rich values. is a lean value within or below the set if values listed by vag-com and rich above the values?

Sure you can. If there is black soot/carbon crap on it, thats a pretty clear indicator that its fouled. He said it happended right after he seafoamed which is why I mentioned it.


Replace your MAF!