P0507 and G freak out after WOT
#1
02-08-2023, 07:29 PM
P0507 and G freak out after WOT
Going to need someone to explain this one to me, if you want some other context on symptoms i’m experiencing I have a separate thread open. Earlier today I was at a stoplight when a 5.0 Mustang rolled up on me, revving like he wanted to run it, so we ran it. I dropped it into first gear, and we went on green. I honestly was pleased with the race. We let off around 60, and he didn’t even gap me. Right after this however, I could tell something was wrong immidiately. RPMs started to bounce all over the place, and throttle response was really off, I pulled over and put it in park to see if i blew a line or something, and RPMs went above 1k and sat. Everything in the engine bay seemed sound, so I started scanning and pulled P0507, along with high voltage on both downstream sensors. I was looking at live data on my bluetooth obd tablet, and saw maxed out fuel trims at 25% each, fuel status says open loop(sys fail), AFR is sitting lean around 15.2, as well as Control Module voltage above 17V, yet voltage to the obd as well as voltage on my radar scanner we’re both normal at 14.6 (charging voltage). At this point I have a CEL, and the car is in limp mode. So i’m limping back home, and all the sudden everything goes back to normal. I’m figuring that i would find something back at my driveway, but nothing. I scanned, revved the car, watched live data, nothing seemed too out of place. Any thoughts?
#2
02-10-2023, 12:25 PM
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I'm assuming this all happened when you were down in Mexico on your recent vacation since posting about street racing is a violation of the terms of use on this site 
If I had to guess I'd say the crankcase pressure from the high rpm under load gummed up your PCV valve for a second, then it unstuck itself.
Unscrew the PCV valve, give it a good shake to make sure it's rattling smoothly, if it feels gummed up at all that was probably what happened. Regardless I would clean it thoroughly with some brake parts cleaner.
When the PCV valve sticks the intake plenum is free to suck as much air as it can from down inside the engine crankcase, this is all post-MAF so it causes a really high idle and lean condition until it starts to draw a vacuum on the crankcase and pressures even out. At that point the PCV valve probably shut itself once pressure stabilized.
If your engine drinks oil this is even more likely since the rings are bleeding off more pressure, thus more oily mess being sucked up the PCV and a higher volume of crankcase air being ingested back into the engine.
If I had to guess I'd say the crankcase pressure from the high rpm under load gummed up your PCV valve for a second, then it unstuck itself.
Unscrew the PCV valve, give it a good shake to make sure it's rattling smoothly, if it feels gummed up at all that was probably what happened. Regardless I would clean it thoroughly with some brake parts cleaner.
When the PCV valve sticks the intake plenum is free to suck as much air as it can from down inside the engine crankcase, this is all post-MAF so it causes a really high idle and lean condition until it starts to draw a vacuum on the crankcase and pressures even out. At that point the PCV valve probably shut itself once pressure stabilized.
If your engine drinks oil this is even more likely since the rings are bleeding off more pressure, thus more oily mess being sucked up the PCV and a higher volume of crankcase air being ingested back into the engine.
#3
02-10-2023, 03:09 PM
I'm assuming this all happened when you were down in Mexico on your recent vacation since posting about street racing is a violation of the terms of use on this site
If I had to guess I'd say the crankcase pressure from the high rpm under load gummed up your PCV valve for a second, then it unstuck itself.
Unscrew the PCV valve, give it a good shake to make sure it's rattling smoothly, if it feels gummed up at all that was probably what happened. Regardless I would clean it thoroughly with some brake parts cleaner.
When the PCV valve sticks the intake plenum is free to suck as much air as it can from down inside the engine crankcase, this is all post-MAF so it causes a really high idle and lean condition until it starts to draw a vacuum on the crankcase and pressures even out. At that point the PCV valve probably shut itself once pressure stabilized.
If your engine drinks oil this is even more likely since the rings are bleeding off more pressure, thus more oily mess being sucked up the PCV and a higher volume of crankcase air being ingested back into the engine.
If I had to guess I'd say the crankcase pressure from the high rpm under load gummed up your PCV valve for a second, then it unstuck itself.
Unscrew the PCV valve, give it a good shake to make sure it's rattling smoothly, if it feels gummed up at all that was probably what happened. Regardless I would clean it thoroughly with some brake parts cleaner.
When the PCV valve sticks the intake plenum is free to suck as much air as it can from down inside the engine crankcase, this is all post-MAF so it causes a really high idle and lean condition until it starts to draw a vacuum on the crankcase and pressures even out. At that point the PCV valve probably shut itself once pressure stabilized.
If your engine drinks oil this is even more likely since the rings are bleeding off more pressure, thus more oily mess being sucked up the PCV and a higher volume of crankcase air being ingested back into the engine.
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