P0172 And P0175 What to Look For

good everybody welcome to today's video in today's video we're going to look at the engine codes p0172 p0175 system two rich this is another one i get a lot of questions on on my channel now just to give you a little pointer here always look at your long-term fuel trim when it is rich at certain conditions negative value at that airflow indicating decreased fuel is needed so once again we're going to start off with the maf sensor because map sensor in the previous video we talked about how it could give your engine a lean code but it could also make it run rich as well and this comes down to the mass sensor being faulty maybe it's dirty dirty is a very common one because i use this stylo filter and it's one of those oiled filters and it's very common that if the map sensor gets the oil on it gives it a wrong reading now how that does that is the mass of air entering the engine is actually less than what the map sensor is indicating to the pcm the pcm delivers more fuel for more air that is actually entering the engine and this is very common if you start up your vehicle and your map sensor is faulty it'll run rich especially at idle you might get some black smoke coming out the exhaust but it'll be definitely running rich it's gonna almost feel like it's choking out now we go to the fuel system as well if you guys remember a few videos i did on the fuel pressure regulator this also comes down to the engine running lean like i talked about before where i pulled the vacuum line off and then the fuel pressure jumped from 50 to 58 now 58 psi i could tell at idle on this vortec motor it's starting to run rich and that's why if the diaphragm inside is getting bad or weak you might have intermittent issues with the fuel pressure jumping around making your engine run rich and i also talked about this in the uh fuel pressure video i need a light so the fuel pressure regulator of course if you pull this line off and there's evidence of fuel that means that it's bad and that could be a reason why you're running rich fuel injectors are a big one when it comes to running rich because if the fuel injector is starting to stick if it's not sealing properly it's allowing more fuel into the engine making it run rich now if you've been following this video series on the fuel pressure regulator i talked about on the ford that i have a fuel rail pressure sensor and if this sensor is faulty it could give the wrong readings to the pcm and then the pcm could send a higher duty cycle to the fuel pump driver module causing high fuel pressure and we talked about that in the fuel pressure video that too much fuel pressure then what the load is demanding will cause it to run rich now if you're kind of curious about the fuel pressure driver module i did a video on diagnosing and testing the fuel pump driver module if you want to learn a little bit more on that but we're just kind of keeping this to these trouble codes there's so many variables there's no evap on this to show you but the evap has a purge valve you guys see me do videos on it on my bmw uh if you watch me when i built this i actually removed the purge valve out of the jeep 4.0 it was down there now if that purge valve is faulty it could introduce fuel vapors into the motor when it's not needed causing it to run rich this is something that's very important and sometimes overlooked believe it or not and this is for the people who don't do their own maintenance our follow maintenance on their vehicle is that you can actually have a rich condition if your air filter has not been changed if your air filter is dirty not enough air flow is going into the engine and essentially you're choking it out now the maf sensor and the other sensors can compensate for it for a little bit but once it goes outside of those variables that's where you're gonna get the code trigger you that's saying you're running rich always check your air filter it's quick and dirty if anybody has ever had an extremely dirty air filter you'll know especially on a small motor on a small motor it's most noticeable because there's no computers or any of that thing it will choke itself out it will choke itself out so like i said there's a huge amount of variables to go over and one of the common questions i get from people um sometimes this issue happens after they've been wrenching on their vehicle they never had that problem before but also they do it's definitely related to something you did along the way i've been guilty of it too i had an issue on my bmw years ago is that i replaced the valve cover gaskets and then i did a whole bunch of other work too but when i restart the vehicle all sudden is telling me it's running lean my long term fuel pressure trims short term or way out to lunch and what had happened was that the valve cover gasket had rolled but that's should have actually said that on the other video because this one's talking about rich talking about the engine being fooled into running rich so now that those videos are out of the way i'm gonna start looking at diagnosing various parts i could talk about the map sensor and then do videos on diagnosing that using a scanner reading the data comparing the data before and after cleaning it and all that so i hope you guys enjoyed this video if you have any questions or comments post them below i'll see the next one

Channel: BSK Garage

Views: 98,906

Keywords: BSK Garage, P0175, P0172, chevy, ford, gmc, training, rich, car, fuel, truck, fuel regulator, faulty fuel injectors, air filter, motor run, Maf sensor, P0175 engine code, chevrolet, mercedes, gm, pontiac, engine, rich condition, variables

Id: XWCX9d4B0Y0

Length: 6min 50sec (410 seconds)

Published: Mon Dec 14 2020