Evening Scotty!
I have a 2005 dodge Dakota st 3.7l v6 4x4 automatic 124147 miles. I had replaced the starter about three months ago along with plugs injectors and coils. I got codes po 172 and po 175.
So I went back over everything could not find anything wrong. I checked air filter when getting home. Nothing wrong next day before starting truck checked air box again and smelled gas. And sure enough when I started it dreaded check engine light same codes. So I assumed the injectors were leaking so since under warranty had them replaced. Put new ones in still had the codes. So checked the fuel pressure and it was low. So replaced the fuel pump in the tank with a bosch 67744 fuel pump and housing assembly. had been having starting issues also when it was warm outside last summer. While there replaced the charcoal canister with the leak detection pump and filter. also cleaned the gas tank. So got it finally fired up after today after about 3 months and took for a test drive. I noticed the gas tank was dropping more than it should. Got Home checked the codes still po172 and po 175. I am lost as to the problem? I also replaced the Map sensor also while working under the hood. I rechecked over everything and can not find any issues. Do you have any ideas scotty? Thanks I am lost for words.
Could it be the computer?? It was fine until after I started all this? By the way first time back after installing starter it would not let me clear the codes. Today it would let me clear the codes.
Also when I work on my stuff I always unhook battery completely.
Thanks for your help I am sure you will know!! 🙂
Brian
Well unfortunately you're going the guess route Ion fixing cars. If I were you I would pay a mechanic like me to hook up a very high level scan tool take it for a road test analyze the data for some reason the vehicle is running rich then you'll get bad gas mileage. There are literally dozens of things that can cause that and the live data and historical data on a fancy scan tool being analyzed by mechanic will always find the fault. Jesse is expensive and often doesn't work. Now I have no idea what type of injectors were put on perhaps somebody put the wrong injectors on wrong injectors will flow incorrectly
Morning
Ok thank you scotty I hope I can find someone close to me that knows something? That is a hard job around this small town of Chatham VA . I have the scan tool you recommended blue driver. Would there be anything I should look for in the data that would stand out?
Brian
You may want to use your BlueDriver to look at the Live Data fuel trims to see if those negative fuel trims get better or worse under different RPMs and engine loads.
Check what the ECT and the IAT sensors are reporting during cold start through operating temp.
Make sure that new MAP sensor is reporting the right pressure to begin with at key on, engine off.
Watch your O2 sensor voltages during warm up to make sure their heater circuits are ok and they're heating up fast enough.
Look at the EGR Desired and EGR Actual positions to make sure they aren't off by too much.
Make sure the Evap Purge valve isn't leaking.
Your engine is getting up there in age so maybe make sure that this isn't a case of gasoline vapors getting past the piston rings and into the crankcase and being sucked into the intake through the PCV valve. You could unplug the PCV valve hose and then plug up the side going to the intake manifold and watch if the negative fuel trims start getting better.
You can check your fuel pressure and make sure it isn't too high.
Also look at the Freeze Frame data from when those codes are being set. Again, is it always at a certain rpm range or load range or engine temperature, or are they randomly being set throughout all engine speeds and loads? Record the data, clear the codes, and then when the codes return look at the Freeze Frame again. You'll have to do it several times to see if there's a pattern.
In the end, if everything else checks out OK then it may come down to if you used OEM fuel injectors or aftermarkets which may not have been manufactured to spec and are putting too much fuel into the cylinders. (a big clue would be if you checked out all this other stuff and the high negative fuel trims are happening throughout all engine rpms, loads, and engine temperatures)
Thank you so much sir! Yes i know it is getting up there in age and mileage. But it has been good since i got it in 08. Plus being disabled and very low fixed income for both of us just mine It would be hard if not impossible to get another one.
I will do all that and if I remember correctly from earlier today looking at the data the fuel trims yes all the neg high trims were in all rms. Yes they were after market ones. I was wondering about the bosch ones from RockAuto?
Thank you for your help.
Brian