Throwing a CEL after adding an intake and headers

[Mister Z]

So I added an injen cai and megan headers recently and I have a CEL. According to my obd II scanner I got codes for p0171 and p2195. Those codes lead to running lean/rich and a bad O2 sensor. But I changed the O2 sensor when I added the intake and headers. Any idea on how to fix this problem?!

[cali yaris]

Did you make your ECU relearn after the install?

Why did you change O2 sensors? Did you use a factory O2 sensor?

Have you tried putting the old sensor back on?

[Mister Z]

I changed out the O2 sensor because the oem one was hard to remove from the stock exhaust manifold. I didn't want to strip it so I left it there. I bought a denso brand o2 sensor. And I did unplug the battery after I changed it out.

[cali yaris]

gotta unplug the battery for a while, > 10 minutes at least. is the O2 sensor a Toyota factory sensor?

[Mister Z]

ok. Will do that. I think it is but my mechanic is the one who purchased it. As far as I know the manufacture for the O2 sensor I bought is Denso.

[Cap]

I got codes for p0171 and p2195. Those codes lead to running lean/rich and a bad O2 sensor.

Lets be more accurate..

P0171 is System lean Bank One .. Sys lean is is likely because the Intake you put on is too big.. and the MAF Voltage coming to the ECU, does not match what it will call 'Normal'.. and It's having to add too much fuel..

That is not a 'Rich/lean' ... it's a you screwed up the Calibration of the MAF by the Aftermarket Intake thing.. Tototas really like Stock Intakes..

Cap

[Brian]

Lets be more accurate..

P0171 is System lean Bank One .. Sys lean is is likely because the Intake you put on is too big.. and the MAF Voltage coming to the ECU, does not match what it will call 'Normal'.. and It's having to add too much fuel..

That is not a 'Rich/lean' ... it's a you screwed up the Calibration of the MAF by the Aftermarket Intake thing.. Tototas really like Stock Intakes..

Cap

The Injen intake isn't too big

[Mister Z]

I removed the battery over night and still got the check engine light again. And the same codes. Does running lean affect the engine life, any idea? Thanks

[Brian]

Running too lean is bad. Did you try swapping the old O2 sensor back in? If not, I would try that before anything else.

[malibuguy]

check for leaks

make sure the MAF is fully seated & tight along with all coupler connections

[cali yaris]

it's a you screwed up the Calibration of the MAF by the Aftermarket Intake thing..

The Injen CAI is the same size as all the other major brands, and it's rare that they ever throw any CEL codes. So this is just incorrect. I ran one myself for two years with no problems whatsoever.

However, if the MAF sensor is not seated properly or sealed properly, a lead would definitly cause that CEL.

[Mister Z]

aite thanks guys! I'll check this out!

[bzinn 1]

Recheck the hose that goes to the throttle body from the intake,the big one that hooks it together,if there is air gettign inthere you can get that cel code,get them on scions all the time with intake installs and they go away after reposition and retighten,also check the map and make sure it was installed nice and snug,no leaks,and then check to see the filter is on with no leaks.Then check the engine breather tube that got moved around and make sure it is plugged in correctly.

Alsways make sure the battery is unhooked when doing all this then rehook and let idle for a few minutes and then take for a gentle drive and it will relearn its map needs.

Could be o2 sensor is not hooked up as well,sometimes they dont snap into the plug and the wire is loose....

give it all a try and see what does the trick,if nothing then let us all know and we can try somehting else.

[Cap]

If the Cell Stays after all the Hose Checks.. Look at the Fuel Trim.. Post them..

Then Put the Stock Intake back on.. Run it for a While.. then read the Fuel trims..

I have a PPE intake that will always push the Long term Fuel Trim past 20.. and toss a Cell .. Something about the way it was welded together.. Must not have fit in the Fixture Properly..

Cap

[Mister Z]

Hey guys I check the afr and its reading 14.6 is that the ideal afr? I did the checks and pretty much reinstalled the intake and still got the cel.

[cali yaris]

14.6 is normal idle or flat cruising air/fuel

[Mister Z]

Should I check the afr while driving to see if it makes a difference?

[auxmike]

I've used AFE intakes, no prob. My K&N drop in threw a light once. But once I reset it with the Scangage II, all was well.
Hope you figure it outv and it's not an exhaust leak at the manifold sucking in extra air and leaning you out too much...
I took all that crap off my car last year, my TRD exhaust is my only mod. It's designed by Toyota and thus doesn't screw up my car...:) I also mounted genuine toyota 7 spoke rims. Perfect fit and the car drives nice with the extra 1/2" width (6 inch).

[cali yaris]

I think you need to figure out first if it's the intake or the exhaust. You've made two mods, and don't know yet which one is causing the CEL. Remove the one that's easier and see if you still get the CEL. Best way to test.

[Cap]

14.7 is Good.. That is what you should have.. 14.6 is Fine too.. where was this Reading Taken.. Before or After the Cat.. The only difference After Cat is the Reading will be Dampened.. and the Dithering will be Gone.. Before Cat is REALLY hard to read.. as it always Moving..

Your Lean Code Lite is not really saying the Car is running Lean .. It's saying that it's having to add too Much fuel to get it back to 14.7, from where it should be..

The Danger is Lean at WOT.. If you have a LTFT of < Say> + 22.. This will toss a Cell at you,( lean Code ) and will still run 14.7 on the Road.. But at WOT it MIGHT not be able to Keep the Mixture above 13.5, as the Fueling Choices are done based upon How much Fuel it had to Add During Closed Loop.. and when in Open Loop and the Fuel Trim is past about 15.. ( Plus or Minus ) the Fueling gets Weird..

A Cell will be tossed when the LTFT gets Greater than 20 either + or Minus..

If you can Check WOT fuel Mixture ( Veh Mounted Wideband ).. and the Mixtures are in the Low 13's your good to go.. However.. if the ECU is tossing you a Cell because the LTFT is greater than 20.. chances are you MIGHT be lean at WOT.. Check Them


If you are at 14.6.. chances are you do not have an Exhaust leak.. ( If you were at 14 or richer I say Yes.. ) and the O2 Sensor/ Exhaust Leak is the Problem.. Looks like it is Not.. as the Fuel Mixture is Proper for Closed Loop

Put the Stock Intake back on.. Leave the Exhaust alone.. as it will not affect the Fuel Trims.. Do a few runs on the Old Intake.. ( Engine Cycles from cold to Hot . ) then look at the Fuel Trim.. Long and Short..

If the Long or Short are Greater than 5 each then you Likely have a Plugged Fuel Injector.. Either Swap them out.. or Pull them and Get them Cleaned..

IF the Fuel trim DO settle in the less than 5 Range ( 7 is ok Too ) then I say Something is Up with the Intake.. Either it's too Ruff inside causing a Bad Read.. or the MAF mounting Surface is Mounter Crooked in the Tube.. or it's too big


Cell's and Mods Kinda go hand in Hand.. but if you can Keep Chasing them down. and Dont let them Kick your A$$. then the ECU really is your Friend..

Cap