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Joined: Oct 2003
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Pizza Geek
2002 Toyota Celica GT
Pizza Geek
2002 Toyota Celica GT
Joined: Oct 2003
Posts: 1,547
Likes: 1
Question, I had a custom exhaust run from the header back, removing the cat and had a better res. put in. It was fine for 2 days and then the CEL came on, I reset the ECU and it was fine for another day or 2 and then came on again. Is there anything that I can do, short of removing the light bulb? I had them put the 2 02 sensors in the same place but the cat was removed so it's probably getting a real rich reading. It's really not a problem but was wondering if some had a solution. thanks in ADV. thumbsup

Joined: Oct 2002
Posts: 2,667
ECelica Staff
ECelica Staff
Joined: Oct 2002
Posts: 2,667
The removal of the Cat is your problem, those two sensors work together ... one is suppose to take the reading before the cat, the other after.

By removing the Cat, it is throwing off the ECU and you will always get a CEL now. I believe the ECU is now always confused to it goes to a pre-program a/f curve to protect the engine, it's not going to make any adjustments, so by removing the car I don't believe you are getting the gain that you hoped for.

Last edited by RicePowered; Nov 7, 2003 1:53pm.

Joined: Aug 2003
Posts: 392
sappy
2002 Toyota Celica GT
sappy
2002 Toyota Celica GT
Joined: Aug 2003
Posts: 392
Would that hurt perf.???? Cutting the cat off and all?? Seems like it would lose back pressure.


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Joined: Oct 2002
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ECelica Staff
ECelica Staff
Joined: Oct 2002
Posts: 2,667
Originally Posted by saspence22
Would that hurt perf.???? Cutting the cat off and all?? Seems like it would lose back pressure.

no back pressure is great for high reving ... you will loose power on the low and midrange.

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Pizza Geek
2002 Toyota Celica GT
Pizza Geek
2002 Toyota Celica GT
Joined: Oct 2003
Posts: 1,547
Likes: 1
ok, so just ignore the light?

Joined: Oct 2003
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Pizza Geek
2002 Toyota Celica GT
Pizza Geek
2002 Toyota Celica GT
Joined: Oct 2003
Posts: 1,547
Likes: 1
I have actually notice a big improvement in the hole shot

Joined: Aug 2003
Posts: 392
sappy
2002 Toyota Celica GT
sappy
2002 Toyota Celica GT
Joined: Aug 2003
Posts: 392
Wow...I always thought it was a bad idea to cut that off!! I was wrong I guess. So, if I had a larger pipe ran from the headers, cut the cat off and ran no muffler or a glass pack; It would be better than what I have now?? (No res. and glass pack)


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Joined: Oct 2002
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ECelica Staff
ECelica Staff
Joined: Oct 2002
Posts: 2,667
I don't know about any kind of gains but I know that the ECU goes into a protect mode when those two sensors are NOT working correctly.

It says so right in the Toyota Maintenance Manual. I don't remember 100% but I doubt it's very good for the engine. I'd have to read it again.

Joined: Oct 2003
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Pizza Geek
2002 Toyota Celica GT
Pizza Geek
2002 Toyota Celica GT
Joined: Oct 2003
Posts: 1,547
Likes: 1
KEEP the res. I took it off at first and you could hear it for miles!!! rofl but I have a 2.5in pipe and it make a big dif.!!!!! thumbsup

Joined: Sep 2003
Posts: 45
Member
2002 Toyota Celica
Member
2002 Toyota Celica
Joined: Sep 2003
Posts: 45
is custom piping better confused do you feel a lot of difference confused wave wave

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Pizza Geek
2002 Toyota Celica GT
Pizza Geek
2002 Toyota Celica GT
Joined: Oct 2003
Posts: 1,547
Likes: 1
I never had a name brand aftermarket exhaust, but over the stock exhaust there is a huge difference in the lower end.

Joined: Nov 2003
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Member
2000 Toyota Celica
Member
2000 Toyota Celica
Joined: Nov 2003
Posts: 242
Likes: 1
removing the cat is a big improvment in performance for the celica gts! but unfortunatly the ecu clamps down on the gains after a few days.the only way it can be done without the ecu messing things up is to get one of those devices that immitates the second o2 sensor(showing a normal reading of o2 to the computer).


HYBRID:resulting from the combination of two or more mechanically dissimilar origins!
"...... code":every man is a shadow,let him be treated as such,until proven otherwise by a show of character or code!

Joined: Apr 2003
Posts: 894
Senior Member
Senior Member
Joined: Apr 2003
Posts: 894
Originally Posted by hybridcelica
removing the cat is a big improvment in performance for the celica gts! but unfortunatly the ecu clamps down on the gains after a few days.the only way it can be done without the ecu messing things up is to get one of those devices that immitates the second o2 sensor(showing a normal reading of o2 to the computer).
i've heard of these, but where can you find one for the celi?


rip celi...
95 240sx

Joined: Nov 2003
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Member
2000 Toyota Celica
Member
2000 Toyota Celica
Joined: Nov 2003
Posts: 242
Likes: 1
Originally Posted by element_celica
Originally Posted by hybridcelica
removing the cat is a big improvment in performance for the celica gts! but unfortunatly the ecu clamps down on the gains after a few days.the only way it can be done without the ecu messing things up is to get one of those devices that immitates the second o2 sensor(showing a normal reading of o2 to the computer).
i've heard of these, but where can you find one for the celi?
you can search the forums for the info on how to make one or you can contact splitsecond.com this is a partial clip message from splitsecond.
"We have the ESC2 which connects to the rear O2 sensor(s). It keeps the
>check engine light from coming on when you take off the cat.

>Regards,

>Mark "
hope you get it soughted out,its an awsome feeling with you cat out,right!



HYBRID:resulting from the combination of two or more mechanically dissimilar origins!
"...... code":every man is a shadow,let him be treated as such,until proven otherwise by a show of character or code!
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