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Greetings. Things were going well with the Bentley until I decided to change valve cover gaskets. I have double checked my work and I now get P2189 that comes on after driving for a while. I cannot find any vacuum leaks. Here is a picture of something that looks strange with the 3/4 air flow sensor reading. Any suggestions of next steps?
Well, I took everything back apart on bank 2. I applied a new bank 2 valve cover gasket carefully making sure everything was lined up and seated properly. I torqued to specifications. Installed a new intake gasket and torqued accordingly. I inspected all of the hoses for cracks and no cracks were found. I checked the dip stick and oil fill cap. Fired it up and drove and after 10 minutes of driving the mil came on with the p2189 code again. The fuel trim is definitely off. I tried spraying starter fluid and nothing changed. I guess my next step is a smoke test. My car was perfect until I decided to fix a minor valve cover oil leak. Anyone have any other suggestions?
A couple of easier things to consider other than a bad upstream O2 sensor which would be a nightmare to change.
I found a bad MAF once. The wiring on these original factory MAFs is suspect, the pins lose contact in the harness connector. MAFs basically work like a variable resistor. These can get "flat spots" with age where, at some point along its range, it delivers an inaccurate voltage. The ECU sees/responds to the air volume the MAF is saying but it is not correct so the ECU under fuels at that point.
In another case that also actually impacted my car - Any air leak that occurs PAST the MAF and before entering into the intake port will create a lean fuel trim condition. This includes all of the piping PAST the MAF that travels into and out of the front coolers. I found that one of the elbows slipped off at the cooler underneath and behind the front pan. This allowed more air entering into the "mix" after the MAF measured it. It was most prominent at idle as the elbow slipped off creating only a slight gap. At speed not enough additional air entered that fuel trims couldn't correct, just worst at idle.
Thank you BWings. I thought that I had this issue resolved on Saturday. I cleaned the map sensor with appropriate cleaner. Checked the wiring on the plug and associated connections. I tool out the filter and seated the air filter housing making sure it was in the turbo flange properly and put filter and cover back on. Took it for a drive and surprisingly there was no light.
Today I toke it out for an eye appointment and the light is back on. After my appointment I will scan it again. Attached are the fuel trim numbers after I cleaned the map sensor.
Well I hooked up vcds and there was no lean code. The fuel trims looked good. There were multiple misfire codes from bank 2. I cleared the codes and took it for a 30 minute 70 mph run and no check engine light. Ran an auto scan and everything was clear. The only thing I did on the way to the doctors office was get some gas, with the engine running. The cel light came on shortly after. I am going to call it good for now. I will take it out this weekend and report back.
I am still dealing with this p2189 code. Johnny do you have a part number for this turbo gasket. The inlet is sort of loose. Also I want to replace the mass air plug. If anyone has a part number I appreciate it.
thanks
Finally had time to work on the Bentley. What I discovered was the breather pipe on bank 2 by the oil fill was in the valve cover but it was not snapped tight. It looked ok visually. I inadvertently found it when trying to take it out to check the o-ring. Thanks to all who offered suggestions for a fix.
I took it on a long drive in the city monitoring trims. Short term fuel trim at idle is -1 to 0.
