So last weekend I overhauled the cooling system. It went smoothly with the help of the posts on this forum. After bleeding the system, I drove the car a couple hours to make sure everything was OK and everything was. Temp was good. Coolant level was good. Car running perfect like before. Today my wife took the car to work (about a 20-30 min drive) and the SES light came on. When she got home from work, I got Autozone to run the code and it gave me the P0171 code. I'm wondering if this is a result of me removing and re-installing the air box incorrectly. Anyone got any ideas? What should I look for?
hawk22
It helps us if you identify your car. We can't tell what year, or what engine. If you plan to use this forum in future, please create a sig with that info. Take a look at mine.
I assume a six, and that code is System Too Lean (Bank 1). This is the front three cylinders. Not related to your work.
Air leak in the intake manifold? I'd clear the code, and see if it comes back.
I assume a six, and that code is System Too Lean (Bank 1). This is the front three cylinders. Not related to your work.
Air leak in the intake manifold? I'd clear the code, and see if it comes back.
The seal at the connection between the throttle body boot and the MAF elbow (pardon my French...) might not be airtight. I'm referring to the connection where two thin hose clamps are attached side by side. That's a fairly common spot for a vacuum leak, which would likely cause the O2 sensor to post a "lean" code.
The section of the intake boot closest to the throttle body is on the list of common failures for the M54. Replacing that piece cured my lean code, as well as eliminated the whistle at 1800 rpm. If/when you remove and/or replace any parts from the air box back, as pleiades said, be sure you get an air tight seal on everything or it will probably throw a lean code.
My car started to whistle today after I cleaned my MAF. I checked the boot and did not see any physical damage. However I thought that I saw something fall when I removed the MAF from the air box. There isnt a o-ring that helps seal off the unit is there? My mind may have been playing tricks on me as I could not find anything in the engine compartment or under the car. This is on a M62TU.
Make sure to reconnect ALL your clamps securely. Even the slightest misalignment of hoses and clamps will cause the engine to run lean. My best advice for you will be to take a bright flashlight, and once-over all the connections in the hose intake system. Chances are that either you misaligned a connection, or a rubber boot has deteriorated . After that, try reinstalling the entire intake system [ throttle body hose, maf hose , air box hose ect] . Do them one at a time and be sure you clamped them in the correct place [ as the rubber boot impressions will show] , in the right alignment. This is very trick, and I hade the same exact issue as you, so I think I would know a thing or two about these things :thumbup: Good luck
Just got back in from double checking. Took the boot off and reinspected. My boot is made of a hard plastic . I did take notice that there is a rubber ring on the outside lip of the TB and was in great shape. Boot to MAF was just that. No rubber ring. MAF to air box did have a o-ring present. All was fine for 70 miles or so until I had to go wide open on the throttle to avoid being ran over by a semi. Thats when the CEL came on. Once I arrived in my brother subdivision I noticed a high pitched whistle similar to a turbo. Im not sure of the rpms it was producing the whistle but it was at a lower speed. 15mph or so. Also getting some intermitent hard downshifts as well. I will need to pull the code\s to give me a better idea of whats going on. I did notice that the bolt below the airtube that secures the tube was missing. I never removed that. Never even noticed it until tonight.
Just had codes pulled. P0171 P0174 I have cleaned MAF twice now and checked connections countless times. I think the MAF has failed on me.
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