Code p0171

[BaseRunner]

Hi all, first time poster here :hello:. I changed my front cat today and when i was driving it home i smelled a strange smell. When i got to my house i parked the car and took a look underneath and i could see a little bit of smoke (im wondering could it have been because of the welding?) anyway the smoke went away but it took a while for the smell to go away. At the same time my truck was idling rough and it was hard to accelerate. I decided to go on the highway and drive it for a little bit and it was a mixed feeling to be honest because i dont know if i had gotten any power from changing my cats. I pulled over and i cleared my cel code for the cat and started driving again. 5 mins later the check engine light pops back on so i pulled over to see what it was. I scanned it with my scangauge and it showed p0171 I drove it around for a little longer and POOF the check engine light goes off. If any of you guys could shed some light on this i would greatly appreciate it. Thanks in Advance guys!!!:thanks:.

Btw ive already got a fuel injection cleaning, transmission flush, downstream oxygen sensor change, front cat replaced and egr valve replaced.

 

[Brian757]

Manufacturers often put oil or another lubricant in their mufflers and catalytic converters to preserve the internal components. Once installed and the car runs, it burns these oils and such. When you put a new muffler in, the oil doesnt pass through the o2 sensor, but a new catalytic converter will pass the burning substance past the o2 sensor. It will pass, also, it does smell pretty bad. Just let time take care of it.

My Magnaflow system smelled bad for about a week. It wont be long.

 

[BaseRunner]

So you think the check engine light coming on was a fluke? I really appreciate the response thanks man!

 

[Brian757]

So you think the check engine light coming on was a fluke? I really appreciate the response thanks man!

It might have just been a fluke. And your welcome. The o2 sensor could have just gotten a bit dirty from the oil and it threw the switch. Clean it out and pop it back in. I would ask if you just clamped the connections or actually did it right and welded the joints but you asked if it "was the welds causing the smoke," so that answered my question. The reason I would ask is because your code, p0171, is a code that is caused from having a "system too lean". This means you might have an "exhaust leak" which would be caused from clamping pipes and not properly welding them. (But does apply to you obviously)

So my other guess would be the catalytic converters residue caused the o2 to malfunction. No worries, the cat is just breaking itself in.

P.S. - Smoke coming out of the tail pipe is COMPLETELY normal after a new catalytic converter/ aftermarket muffler install. It is only temporary.

 

[BaseRunner]

Yea I had a shop put em on for me and it turned out the cat i had ordered myself was $254 and it didnt even fit!!:redbrick: but the shop is a pretty cool place, they offered me a cat and labor for only $220 :thumb3: some good honest people there! but yea Your right it was probably the catalytic converter breaking itself in. The reason i say that is because ive been driving the car constantly today to see a difference and on my scangauge it showed a lot difference in the gas mileage area. Also the shaking rough idling has all gone! Im just learning about my Runner and Man that had me worried there because i did not wanna spend more cash on another problem. I appreciate the info your a cool dude thanks!

 

[Brian757]

Yupp. Any time. Glad your 4runner is okay. And continue to use this forum for anything 4Runner. There are so many informative and helpful people on here it is ridiculous. Good luck!

- Brian

 

[BaseRunner]

Yea even though that was my first post ive been using this website for quite a while, and ive seen how everybody helps everybody and i must say that is pretty cool to see. Im glad im now a member too, its a very helpful place.