Throwing a CEL after adding an intake and headers - Page 2 - Toyota Yaris Forums

cali yaris · 07-28-2011, 12:35 AM

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 · 07-28-2011, 07:33 AM

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

07-28-2011, 12:35 AM	#19
cali yaris ULTIMATE View User's Garage Drives: 07 Yaris Turbo Join Date: May 2007 Location: Canoga Park, CA Posts: 14,859	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. __________________ Micro Image forums, online store and shop are now closed. It was a great eight year run, but it was time to focus on other things. I'm still selling parts on eBay under micro*image seller ID and customers can still make requests for anything specific.

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07-28-2011, 07:33 AM	#20
Cap Drives: Toyota Join Date: Jun 2009 Location: California Coast Posts: 4	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