2001 530i lean on both banks

**hondadogie** · 06-10-2013, 10:59 AM

My 2001 530i is throwing me P0171 and P0174 codes for lean on both banks. I replaced the intake runner valve last summer and it did not code all winter and spring. Now it is running lean again. Using generic scan tool seems bank 1 is about 20% lean and bank 2 is around 10-15% lean (0 being 14.7:1). Looking for steps to diagnose what the problem is ie. fuel pressure, things to check etc. The car has about 170,000 miles on it.

**Jason5driver** · 06-10-2013, 12:44 PM

Check the Disa Valve (aka: Adjuster Unit) that mounts to the Intake Manifold.

Real OEM link:
http://realoem.com/bmw/showparts.do?...79&hg=11&fg=40

#7 from Diagram:
BMW part number: 11617544805:

I would also check the CCV as well...

A bad CCV can contaminate/ varnish/ oxidize-(coat everything with hardened oil) the Disa with backed-up oil and condensation...
Thus, causing the Disa Valve to not work properly...

Threads explaining function of the Disa Valve:
1. http://forums.bimmerforums.com/forum/showthread.php?t=1457672

2. http://forums.bimmerforums.com/forum/showthread.php?t=1311694

3. http://www.bimmerfest.com/forums/sho...d.php?t=514543

4. http://forum.e46fanatics.com/showthread.php?t=611798

5. http://forum.e46fanatics.com/showthr...highlight=jfoj

**theWalkinator** · 06-10-2013, 01:09 PM

Check vacuum leak.

**hondadogie** · 06-10-2013, 01:57 PM

DISA valve was the intake runner valve I spoke of...already replaced. I believe I found the problem though just now on break-went out to car with a squirt bottle of water and squirted the area where the DISA valve seals to the intake manifold. The top area of that connection sucked the water in immediately. So I believe although the DISA valve is new, it is aftermarket and the seal wasn't as good as an OEM would have been. So I removed the DISA valve and applied a bit of liquid gasket to the seal and re-installed it. Cleared the codes and allowed the car to idle for 20 minutes to re-learn everything. Went out after 20 minutes and my fuel trim is now hovering right around 3-5% lean (down from 20-25% lean). So I will drive tonight and tomorrow while monitoring with a scan tool. Will post results tomorrow.

**rugbycanada** · 07-01-2013, 11:49 PM

I had the same problem.Although the crankcase breather hose was split, (the one that goes to the dipstick housing), it proved to be a failed DISA. Replaced it with an aftermarket and had another issue, which proved to be just a poor connection, but I pulled the DISA to see if I had a bad seal like you. I didn't but glad I took it out as I saw the inside seal where the flap closes was already failing after just 20 minutes! I returned it for an original BMW. $170 more but far less than a rebuild down the road.

**auaq** · 07-02-2013, 08:35 PM

Originally Posted by hondadogie

DISA valve was the intake runner valve I spoke of...already replaced. I believe I found the problem though just now on break-went out to car with a squirt bottle of water and squirted the area where the DISA valve seals to the intake manifold. The top area of that connection sucked the water in immediately. So I believe although the DISA valve is new, it is aftermarket and the seal wasn't as good as an OEM would have been. So I removed the DISA valve and applied a bit of liquid gasket to the seal and re-installed it. Cleared the codes and allowed the car to idle for 20 minutes to re-learn everything. Went out after 20 minutes and my fuel trim is now hovering right around 3-5% lean (down from 20-25% lean). So I will drive tonight and tomorrow while monitoring with a scan tool. Will post results tomorrow.

What do you mean by liquid gasket? RTV silicone? If so, did you leave it out for a minute before installing it back?