1221 Code After Cleaning Up Mess Under Intake

[Petebee]

Okay so about a month ago my buddy and I decided to take a 2 hour drive to try out an 88 M3. Upon seeing/driving the car (it was a POS) I couldn't wait to get back into my 318i for the drive home.

As we headed out to lunch the car started bogging down, throwing a CEL when climbing inclines, and generally running shitty. It had thrown a brief CEL on the way to work a few weeks earlier (same bogging feel for a few seconds).

After getting home I ran the stomp test and got 1222 code, which research says can be vacuum related. So I pop open the hood and listen and can hear hissing from the snake of hoses under the intake.

So I ordered all parts for the overhaul and did the following:

Removed all extra coolant/vacuum hoses
Ran new hose from ICV to intake boot (put a connector in the center of the hose to prevent it from collapsing))
Ran new hose from valve cover to port under throttle body
Cleaned out injectors, new seals
Cleaned ICV
Cleaned all the oily crap out of the intake system
Replaced valve cover gasket (including those damn grommets for the vc bolts...ouch)
New spark plugs, air filter, oil change
New gaskets for intake and throttle body (I left the hold heater plate on without anything connected to it)

Couldn't believe how smooth the car ran. On my test run it was perfect until I decided to push it. On a redline shift (6900 have Dinan chip) from 1st to 2nd car bogged just as LSD kicked ass end in line, and CEL lit up. Ran crappy for about 30 seconds and then smoothed out.

At home ran stomp test and now got a 1221 code (oxy sensor). Thought that perhaps I'd introduced a vacuum leak with the hard shift (engine rocked, pulled on the intake boot and let extra air in), so I decided to take it easy.

Ran good for about a week and now it has started flashing CEL about 3 minutes after startup. I can tell when it is going to happen as the car stumbles about 20 seconds prior to the code flash. Weather has been colder in the morning.

Any thoughts were I should begin? I did attempt to replace the header to cat gasket several years ago, but snapped one of the studs (flange at header to cat) in the process and left it alone. Car does have a slight exhaust leak there I believe.

[Petebee]

Okay so tried to trouble shoot this issue some more. Today I had battery tested and it is fine. I went ahead and replaced the fuel filter (since I had one). Tried spraying propane torch around intake and valve cover area and no smoothing or rise in idle.

Thing is it had gotten progressively worse - stalling, poor idle. Got to where I had to really feather the gas to keep it running while it bogged.

I read some posts that the crank position sensor might be an issue. I do have an oil leak on that side of the timing case (outer profile gasket or tensioner...can't tell). Removed cps and it did have some oil buildup on it.
Cleaned it and no better.

Then I thought maybe I should try the ICV, so I unplugged it and presto, idle smoothed out a bit (car was warm) and revved okay.

I took it for a spin around the block - it still isn't running perfect and now is throwing 1222 code, but we are getting closer.

Any hints?

[io_RobbieRodgers]

Did you go over all the vac lines you replaced and made sure they were still sealed well? Sorry if I'm being captain obvious and this was the first thing you checked... did you also clean up the inside of the manifold well when you deleted that crap? When I pulled mine it was absolutely CAKED on the inside with crap, maybe some of it is blocking the vac ports.

[jrobie79]

check the sensors, they may have gotten loose during the work. CPS and theres two more under there, IIRC that might effect the CEL

[mr ilia]

Check this - There is also a tiny vacuum tube going from FPR to the TB, this may have slipped off the TB or cracked when you worked on your intake.

[Petebee]

Thanks everyone I will double check all vacuum hoses (especially that little one from FPR to throttle body).

I did clean all of the crap out of the intake runners and the fuel injectors - plus added fresh injector seals and small sections of fuel line (where hard lines connect to the rail) for good measure.

[bmwm42]

you have a leak plain and simple and most likely if you pulled the fuel injectors that is where your leak will be spray some carb cleaner etc you find it quick but that code is a vac leak

[Petebee]

I am beginning to lean towards the oxygen sensor. I sprayed propane all along the intake and injectors and no change in idle. The exhaust smells like fuel. I replaced the oxy sensor a year ago, but it was a spliced in connection. Maybe it has failed.

1222Oxygen Sensor Lean/Rich Detect (primary) If the signal from the O2 sensor indicates a very lean or very rich mixture for more than 10 seconds, then the computer generates this code. It could mean a faulty O2 sensor, or a problem with another component.

[Threehz]

Yeah I had a 1222 a while ago however the car was running fine, the CEL would only come on after the car had been running a while and after 10 seconds sitting idle. I threw some Lucas fuel system cleaner in a couple days later and took a 300 mile trip half freeway 55-75 mph and since then it stopped.

Sounds like you have narrowed it down quite a bit though. I hope it's something less expensive then a oxygen sensor.