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Thanks for the input/advice. Because the P0171/174 codes appeared after changing out the the front engine cover (timing cover) gaskets, crankshaft seal, and camshaft cover gaskets, I did think it was a vacuum leak that I introduced. With that in mind, I placed vacuum on the throttle body using the port connected to the PCV hose. I plugged the other camshaft cover hose and sealed off the front end (inlet) of the throttle body and everything was perfect. A vacuum developed and maintained. That told me there were no leaks in the breather hoses, throttle body and intake manifold. Eliminating the intake meant moving on to the crankcase and while I don't have the equipment to do a smoke test, I was able to plug the camshaft cover outlet on one side and blow air into the other camshaft cover. Because the ventilation is supposed to be a sealed system and air was easily flowing, I knew it was a big time crankcase leak as JagV8 and others had noted. While blowing air into the crankcase, I put a 3/8 flexible hose to my ear and moved it about the camshaft cover and timing cover gaskets to see if I could pinpoint the leak. No luck, but I could hear the air escaping so I continued to hunt until I placed it at the crankshaft pulley and lo and behold, there was the leak. I then proceeded to remove the fan/shroud and hoses so I could get a better look/feel. Once I had access, I blew air in while my hand was in front of the crankshaft pulley and I could literally feel the air blowing out! So, off with the power steering pump, relocating the A/C compressor, removing the crankshaft pulley and all of the other equipment necessary to remove the front engine cover. Once off, I looked at the new crankshaft seal I had installed and that was where the problem was. I pressed the seal towards the back of the timing cover, so the crankshaft pulley was not able to seal off because the seal was pressed back to far. I was able to confirm that the seal needs to be flush with the front of the engine cover on this thread: https://www.jaguarforums.com/forum/x...estion-219574/
Tomorrow, I'll put it all back together and sometime after that, I'll send an update. Long story, but the short of it is I'm just a retired guy having some fun wrenching
I looked at the new crankshaft seal I had installed and that was where the problem was. I pressed the seal towards the back of the timing cover, so the crankshaft pulley was not able to seal off because the seal was pressed back to far.
Glen,
What an amazing job of diagnosis! Thank you for posting this very enlightening update! We'll look forward to learning if the lean codes are resolved when you have replaced the crank seal.
All resolved!. Got the engine cover and camshaft covers back on nice and neat and did an air test. Sure enough, air would not flow - meaning the proper placement of the crankshaft seal stopped the air leak. Put it all back together and the fuel trim at idle and 2,200 RPM is captured in the images below. Not sure what they're supposed to be, but they certainly look better than what the numbers were when the air leak was present. All is well in Central Florida and my daughter can now resume taking the car to work
In general, readings of under +/- 10% are considered normal for both the STFT and LTFT, so you're good. Readings of more than +/- 25% will trigger lean or rich DTCs.
04-18-2023, 05:33 AM
