FT86SF UEL Catted Header with CEL

[Infamous_Key]

Disclaimer: This is my first install on my first project. And I’m pretty excited about voiding my warranty

So far, I installed an FT86Speed Factory UEL Catted Header with a Motive Over Pipe. The rest of the pipes are Stock, there’s currently no tune, and the rest of the car is stock (minus Noise Generator... shit shouldn’t have been there in the first place).

With this set up, I shouldn’t get a check engine light, but some magical way I am.
I was trying to do some digging and research from others with my set up but coming up with 2 things. 1) running with a CEL runs rich AFRatio (burns more fuel) I don’t want that. 2) Uncatted header swaps use a tuner to solve their CEL issue after a header install.

I was wondering if I need a tune would knock this problem out or if there is something wrong with my O2 sensors or I fucked up the install 🤦🏽*♂️🤦🏽*♂️

Help ya boy out

[churchx]

Aftermarket header cats are different then stock. Of course O2 readings on cat efficiency & temps can get outside expected ranges. Header being catted in no way prevents CEL, only at best increases time for it to pop up, just like sensor spacers.
Do like others do, ECU tune with cat readiness tests disabled. You can still drive car with cat readiness CEL lit, main drawback - cruise control won't work.

And you should have done homework first. What i wrote above is rather common info. As of now, you have bought more expensive header vs catless, with it will be less gains vs catless, and you still need ECU tune.

[Infamous_Key]

I hear that. I planning on getting a tuner next. I’ll go do some research on them. I know the popular one is an OpenFlashTablet.

I was studying these headers for a while and by biggest draws to them where no CEL, helps torque dip, and they where the best looking and sounding headers vs Borla or Indiva (but that’s all in matter of opinions)

[churchx]

OFT is popular among DIY crowd. Ecutek is more popular overall/among known tuning shops.
I guess ft86sf, when made it, hoped for these to prevent CEL appearing with stock tune .. but IIRC even in thread about those several still reported that got that (eg. here), thus goal was not 100% reached. After all, usually in most aftermarket catted exhaust bits used cats are "highflow", or in other words, - of lesser cell count then stock & lesser emission cleanup efficiency, only toyota knows exactly what parameters/readings to expect from O2 sensor in stock headers, to design something replicating/fooling that, trying will be more of guesswork.
Getting ECU tune is beneficial by itself, providing some power gains even if all the rest is completely stock. And as you saw, it's also needed for CELs to not get thrown. Adding to that, that most legislation regarding emissions does not allow removing / modifying or replacing any stock emission related equipment except with another stock one, there are no pros for catted header on this account too, as this header will still not count as legal.
For all these reasons people deciding on aftermarket exhaust headers usually get catless header + ecu tune, saving money on cheaper and providing more gains headers due absence of cat.
Lot of valuable info is here, in stickied basic bolt on mods guide thread's OP.

In your case i guess you can continue to drive with that CEL (if CEL thrown is P0420 about not passed cat efficiency tests. There is possibility for it being due some other cause) and flash ecu tune with those cat readiness tests disabled (and also for some extra gains). While initial purchase of these headers imho was not the best choice, but you already bought them, thus buying another header makes little financial sense, so make most out of already bought one.

[MCTeeJ]

+1 on getting a pro tune. Your factory header is closer to EL than it is a true UEL, and the stock tune is for that header. Going to a legit UEL design should be reason enough for a re tune, catted or not. I personally recommend an Ecutek Tune from a pro tuner for the 86.

[Infamous_Key]

Well the CEL light is off, I just was going for a test drive last night and it went away before the car finished warming up. Drove it around for a few hours and different roadways and stayed off, drove fine and better than before.

I appreciate for your insight on the topic, but i was just trying to see if someone had a simple solution to (had to be) an simple problem, since FT86SF say they not supposed to throw a CEL; it couldn't have been anything to the level of a tune to turn it off.

Getting a tune is in the works..
Thanks guys

[tomm.brz]

Originally Posted by MCTeeJ

+1 on getting a pro tune. Your factory header is closer to EL than it is a true UEL, and the stock tune is for that header. Going to a legit UEL design should be reason enough for a re tune, catted or not. I personally recommend an Ecutek Tune from a pro tuner for the 86.

i do not agree, sorry but to me looks kinda superficial your answer, stock tune is more emission/economy related

look at stage1 oft ots cams that are more performance oriented, quite different.
stock tune benefits much from a UEL header, so much that the dip almost goes away

of course ecutek is a good idea, i have it and help friends to tune their cars with it
but also an OFt with ots maps is still a nice idea, cheaper and if one is not interested in the ecutek extras, can go without problems with a ots map

[Summerwolf]

The cel will most likely come back. It takes a tune to be rid of it 100%.

You also need a tune to really make use of the header as well.

[chickunfut]

I installed the FT86 catted header without a tune and did not get a CEL. I ran it without a tune for several months and no issues.

Did you start the car without something connected during or after the install? You shouldn't get a CEL with that header.

Scan for codes and go from there. The codes should still be in the ECU even though the light isn't on anymore.

[steve99]

Whats the actual CEL code your getting, if it P 0420 thats cat efficiency, if its a different code you may have exhaust or intake leak or damaged 02 sensor. Dont assume it cat code if you havenypt checked actual code

[KMA KiCKz]

I ran the FT86SF Catted UEL paired with an Invidia N1. Ran it for about 6 months with no problems or CEL. I then went on a long road trip (~3-4 hour constant hwy drive) and the CEL popped up.

This was from an email from FT86SF a while back,

"Most of the time, people can get a CEL from this header when certain situations occur such as sustained rpm on the highway as the O2 sensors do not get enough difference of exhaust fumes between the primary and secondary sensors. Clearing the code by resetting the ecu with a battery disconnect would be your best bet."

Hope this helps!

[Cesium Rainbow]

I've got the same header as you and free OFT off the shelf tune. No CEL. I've run on the stock tune on drives (25 mi. or so away) to the dealer for service and no light. Every car is a little different so it's not like it's impossible that nothing is damaged or otherwise wrong with your car and it's still throwing a code. ANYTHING you change between the first air sensor and the last one can throw a code. I've felt like the OFT has been a good buy solely based on the ability to read codes, reset ECU, monitor and log data. The tune helps but any off the shelf tune won't measure up to a custom tune. It kinda sucks that now that I'm looking at more upgrades and need a full professional tune because professionals don't use OFT, but it will still work for monitoring and the other things I've been using it for. The question I'd be asking myself on the tune is how far you're going to with power upgrades and how fast.


I'm fairly sure you'll see that CEL again. It's not usually til you're convinced that you have the problem solved that it'll pop back on. There are a bunch of types of codes; some will be active but not flip the light on til it happens a number of times in a row. Same goes for the light turning off.



At least if you invest in a tune, you (should) have somebody to help you troubleshoot problems whether it's a manufacturer, tuner or a community like this.


There are cheaper in-between steps if you just want to figure the problem out. There are companies that sell a cable to hook your phone up to the ECU that have no tuning capability. And in the mean time, if you go by any major auto store they'll read your codes for free.