Problem code P0171

[Ehab]

Hi guys, I would appreciate if you could help me with this I got 4runner 2001SR5 149k last OBD2 code P0171 sys too lean maintenance done:
1- New MAF sensor
2- New o2 sensor
3- New Air filter
4- New fuel filter
5- Cleaned fuel injectors
6- Cleaned fuel tank
7- Cleaned throttel body
8- No vacuum leak
9- No exhust leak
10- Removed catalytic converter
11- New spark plugs
12- New spark wires
after all of that nothing sames to work I still got P0171 check engine along with VSC lights too. The car sames to work fine with no symptoms exempt for very bad fuel consumption full tank around 260mil I am disbred her.
what sames to be the problem, did I miss something?

 

[jgue467]

Did ya' check the air induction system, engine coolant temp. sensor, fuel pressure, PCV valve and hose? After all that, only item left is the ECM. Luck. :cowboy:

 

[Ehab]

Did ya' check the air induction system, engine coolant temp. sensor, fuel pressure, PCV valve and hose? After all that, only item left is the ECM. Luck. :cowboy:

Thanx, I just remembered I also changed the PVC vulve, the fuel pressure sames ok about the coolent sensor should that through a direct code.
the ECM how can I check it?

 

[TheDurk]

Thanx, I just remembered I also changed the PVC vulve, the fuel pressure sames ok about the coolent sensor should that through a direct code.
the ECM how can I check it?

Don't trust the ECM to know if coolant sensor is bad. It only knows there is something in the totality of the sensor readings it doesn't like. If one is bad, it won't know which one. It's easy enough to hook up a live scanner and see if the temp readings the ECM has make sense. The ECM will know about an open or short, but lesser fails may not trigger a separate code.

 

[kball]

Put your cat back on and did you change the pre cat O2 sensor or the post cat?

 

[Ehab]

Did ya' check the air induction system, engine coolant temp. sensor, fuel pressure, PCV valve and hose? After all that, only item left is the ECM. Luck. :cowboy:

Guys I have read that that a bad engine coolent sensor will through a different code not P017.
removing the cat convert will decrease the fuel consumption not the opposite it also through a different code.
Yes Kball, I did replace the front o2 sensor the check engine went off for some time and went went back again.

 

[Ehab]

Guys I have read that that a bad engine coolent sensor will through a different code not P017.
removing the cat convert will decrease the fuel consumption not the opposite it also through a different code.
Yes Kball, I did replace the front o2 sensor the check engine went off for some time and went went back again

 

[marshall87]

Sometimes cleaning an injector doesn't help. We had this code before and couple weeks passed.. misfire code popped up. Turned out to be an injector. Both codes went away after replacing said injector.

 

[Ehab]

I had a misfire before cleaning the injectors after cleaning the injectors the car runs fine but I still get the sane code even after reseting the ECU .

 

[Ehab]

Guys would do u think the check engine light VSC light too just went off today by it self, do you think that I may be an electrical problem.

 

[gamefreakgc]

P0171 is almost always a bad O2/MAF or a vacuum leak. How did you check for leaks?

It's a common code to pop up after working on your vehicle, especially if you re-used any old gaskets or misrouted any vacuum hoses.

 

[Ehab]

P0171 is almost always a bad O2/MAF or a vacuum leak. How did you check for leaks?

It's a common code to pop up after working on your vehicle, especially if you re-used any old gaskets or misrouted any vacuum hoses.

If you check my first thread I changed almost every thing, the check engine light went off by it self while I was driving. Actual it's raining and I think it may be a electrical how can I check this.

 

[gamefreakgc]

If you check my first thread I changed almost every thing, the check engine light went off by it self while I was driving. Actual it's raining and I think it may be a electrical how can I check this.

Ok, that helps a little. I read your first post but often people only check for vacuum leaks by looking for cracked hosed but it's more complicated than that. A visual inspection will rarely ever find a vacuum leak unless there is a hose that disconnected. You have to use unlit propane or carb cleaner on a cold engine to actually find the leak.

If you think it's water getting in you'll just need to open the hood in a covered area and see if water is dripping on any wire looms. If yes, then inspect the wiring for any damage where the water might short the wires.

 

[kingin]

Check ground wire conected to your intake manifold, i had same cel last week after new secondary o2 sensor and numerous maf cleanings. Ended up being a loose ground contact.