Catless and the imfamous CEL

[5.0_Lojos]

Question - When going catless will the CEL light turn on automatically after the initial heat cycle/drive? Or can it take time? I've read, days, weeks etc...

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[GrayS550]

I’ve been cat less and the CEL never turned off. I had the spacers too and it didn’t help. I have high flow cats right now and they still haven’t turned off. I think you have to get a tune to turn them off.

 

[5.0_Lojos]

I’ve been cat less and the CEL never turned off. I had the spacers too and it didn’t help. I have high flow cats right now and they still haven’t turned off. I think you have to get a tune to turn them off.

I guess what I'm asking is, Does the CEL turn on right away when the cats are removed? My CEL did not turn on after removal at least not yet.

 

[engineermike]

It has to go through a cat efficiency test and fail more than once. If you’ve driven more than a few miles and held steady state for more than about 10 seconds then it’s done the test at least once, but I believe it take more than one fail to set the code. It actually commands the fueling to cycle between rich and lean and it monitors the rear o2 sensor signal. If the reading switches rich/lean then it knows the cat isn’t working.

Lots of issues that people don’t realize are caused by deleting cats, even if you install anti-foulers and/or turn off the cel. In fact, most tuners and even tuning software won’t allow it anymore.

 

[5.0_Lojos]

Great explanation, Thanks I did primarily since I'm boosted and didn't wanna run into issues melting a cat down the road. I'm adding the 18" bottle vibrant resinators this week to refine the sound and eliminate or reduce the rasp.

 

[WildHorse]

Lots of issues that people don’t realize are caused by deleting cats

Like ? AFAIK FORD logic does it care about p0420/0430, and it's business as usual. No wrench. I asked you this b4 but never got an answer.

I check my logs after thousands of miles being neutered feline free. Fueling is great. Timing is great. MPG is great.

 

[engineermike]

Like ? AFAIK FORD logic does it care about p0420/0430, and it's business as usual. No wrench. I asked you this b4 but never got an answer.

I check my logs after thousands of miles being neutered feline free. Fueling is great. Timing is great. MPG is great.

Explained to you in detail here one week ago:

https://www.mustang6g.com/forums/threads/cat-delete-tune.168747/page-3#post-3932843

 

[5.0_Lojos]

Like ? AFAIK FORD logic does it care about p0420/0430, and it's business as usual. No wrench. I asked you this b4 but never got an answer.

I check my logs after thousands of miles being neutered feline free. Fueling is great. Timing is great. MPG is great.

Ha! that left me thinking also but I assume it's on an N/A application with no tune? My assumption. My daily is a pathfinder and had an O2 sensor give out and it drove like crap and gas mileage suffered. I think in our case if everything is dialed in I don't think it should suffer, at least I hope not.

 

[Unvaxxed]

Big Daddy o2 spacers got rid of the CEL once I got my headers.

 

[WildHorse]

Explained to you in detail here one week ago:

No, I read that. REARs only measure airflow. It doesn't sniff the gasses.

 

[K4fxd]

No, I read that. REARs only measure airflow. It doesn't sniff the gasses.

Ford's logic uses the rear narrow band O2 sensors to fine tune the front widebands. That is what FAOSC does.

If FAOSC is on the rears get a bogus reading and constantly try to get the fronts in range, so to speak. This will cause the ECU to misread the actual lambda.

How far out will it be? IDK, It will be off

If you turn off FAOSC things should be OK due to the widebands using outside air for calibration.

How often do they calibrate? IDK.

If the widebands calibrate everytime you start the car I can't see it being much of an issue even with FAOSC on., unless you are running on the ragged edge. Lots of catless race cars are doing just fine, so I don't think it is a big issue but something to be aware of.

 

[Zrussian13]

TT and Kittyless for 3 years without defoulers and no check engine light. Can't explain why but all my monitors go green.

 

[engineermike]

@K4fxd is right on and I would add that I did test the effects of cats on FAOSC and the difference was 10-15%. So if the cats are gone and FAOSC is still active then your a/f ratio could be off by as much as 1.8 and you’d never know it because your factory widebands are lying to you. I’d also add that many tuning softwares and tuners won’t disable the FAOSC anymore. I’m not so much worried about losing the calibration as I am incorrect calibration.

 

[WildHorse]

FAOSC and the difference was 10-15%.

LOL. Cat delete FI cars on E85 would be blowing up left, right, & center.

 

[engineermike]

LOL. Cat delete FI cars on E85 would be blowing up left, right, & center.

Would they now? So e85 running .88 or .72 lambda is a death sentence? And are we sure “they” didn’t turn off FAOSC? And are we also sure they didn’t dial in lambda based on power rather than lambda?

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