Issues/codes after Vanos seals - but vanos working great
I have searched but have not found much information on my particular issue. Anyway, I bought the double vanos seals from Besian (Thanks Raj) and with the help of my brother (which is a mechanic) we replaced the seals and re-installed the unit. The good news is according to my scanner the exhaust cam is dead on now. If it asks for 113 degrees, the cam is at 113. Intake was always within 1 degree. So the Vanos seal replacement was a success.
Backing up one step; in November I replaced the valve cover gasket. Then it started getting cold here in Houston and the M52TU cold start jolts got worse to where the car would die if you started it and just let it idle. Before then, when it was warm, it would jolt every 20-30 seconds, but never die.
OK, after the first valve cover gasket change, car ran great other than the cold start jolts or sputters. No codes. I also just changed my thermostat because the old one was stuck open and I did have a pending code for cold coolant temp.
Decided to do the Vanos seals, and now I am getting codes P1188, P1189, P0173, P0170, P0130, P0150. So, at first I thought I must have a large vacuum leak. The only vacuum hose on the passenger side of the engine is the one to the air pump valve, but my understanding it is only active during startup (30 sec to a couple minutes). Plus, I checked all along that hose and it is fine and hooked up at both ends (valve and solenoid behind intake). I pulled my air box, pulled the intake hose, cleaned the maf, checked the ccv hose from the valve cover to the ccv and all look intact - no cracks.
Just for giggles, I thought maybe I killed the 02 sensors because at the first startup after the vanos, the exhaust smelled like eggs (it ran rich and had some misses on cylinder 2 and 6) All I did was pull the two coils and tighten them back down and those codes went away).
Now I put two new Bosch front 02 sensors and still the same issue. The scanner shows them at .42 volts with the car off, as soon as I start it, the 02 volts dive down to .02 volts on both banks and it stays there. If I rev the car to 2000 they go only up to .04 volts (not .4 volts) and when I let off it goes back to .02 volts. I am going to remove the valve cover in hopes that somehow a piece of it didn't seal. I can always reuse the vc gasket from November since it so new.
Any words of wisdom?
Current Car 2000 528i, M52TU, 74K miles.