cut cats off need tune....

onebad2v · May 19th, 2008, 03:00 PM

I did a search and couldn't find anything but i'm not really liking the way my car is running after I had my muffler guy cut off my cats and put pipes in place of them. I'm thinking after I get some 4.10 gears I'll have a tuner tune my car but i'm wondering what's wrong...

At idle the car sometimes takes a while to go from.. lets say 1050rpm to normal ~900rpm....and sometimes it will go up and down from 900-1000....I went to the track yesterday and they were racing more for fun and the time board wasn't coming on at first but when it did the guy I was with said my trap speed was only 95mph and i was running only 14.4 at best....

Last week I was getting 14.2-3 consistantly at 97.7mph~....I'm thinking maybe a tune would help the car and I'm not sure but I hear no cats can sometimes make the car run either more lean or too rich but I'm not sure which i'm doing. Any advice would be appreciated.

~C~ · June 12th, 2008, 09:40 PM

I am thinkin of gutting my cats....so been looking into this....and if i am wrong, some one please post. You have an O2 sensor before and after the cats. The ones before need to stay in place and register so the computer knows you have flow going through the exhaust and cats. the ones after register the exhaust post cat. When you eliminate the cat, there is no change in the registry for the front to back O2 sensors. You would need to get a welded bung and tune or just an O2 sensor eliminator kit to take care of this. It will or may throw a check engine code. Tuning it will take care of it.

Hybridbird · June 18th, 2008, 03:50 PM

Get yourself a set of these,
Mustang MIL Eliminators at AmericanMuscle.com - Free Shipping!

Plug them into your rear O2 sensors and then plug your harness back into them,your car will run normal again and you check engine light will go away as well,you're all done. Actually I just saw they don't have them anymore,they are getting hard to find for some reason,but there are about 50 places in the Mustang mags that carry them,you should be able to find some there.

fastpoknee · July 7th, 2008, 03:30 PM

2nd that

zinc02GT · Yesterday, 06:51 PM

Make your own ftmfw

paladinmicro.com

look under DIY MIL Eliminators. Its EXTREMELY simple and works. Worked on mine and it was a total of like $6 at Radioshack

May 19th, 2008, 03:00 PM	#1
onebad2v Newbie Join Date: May 2008 Posts: 29	cut cats off need tune.... I did a search and couldn't find anything but i'm not really liking the way my car is running after I had my muffler guy cut off my cats and put pipes in place of them. I'm thinking after I get some 4.10 gears I'll have a tuner tune my car but i'm wondering what's wrong... At idle the car sometimes takes a while to go from.. lets say 1050rpm to normal ~900rpm....and sometimes it will go up and down from 900-1000....I went to the track yesterday and they were racing more for fun and the time board wasn't coming on at first but when it did the guy I was with said my trap speed was only 95mph and i was running only 14.4 at best.... Last week I was getting 14.2-3 consistantly at 97.7mph~....I'm thinking maybe a tune would help the car and I'm not sure but I hear no cats can sometimes make the car run either more lean or too rich but I'm not sure which i'm doing. Any advice would be appreciated.

June 12th, 2008, 09:40 PM	#2
~C~ Regular Y2K YellowJacket GT ~TBD~ Join Date: Jun 2008 Location: MD Posts: 120	I am thinkin of gutting my cats....so been looking into this....and if i am wrong, some one please post. You have an O2 sensor before and after the cats. The ones before need to stay in place and register so the computer knows you have flow going through the exhaust and cats. the ones after register the exhaust post cat. When you eliminate the cat, there is no change in the registry for the front to back O2 sensors. You would need to get a welded bung and tune or just an O2 sensor eliminator kit to take care of this. It will or may throw a check engine code. Tuning it will take care of it. __________________ Blower in the garage....Install in T-4 days. MILITARY CREW LT "Like the blind man says......We shall see...."

June 18th, 2008, 03:50 PM	#3
Hybridbird Newbie 98 GT Join Date: Dec 2006 Location: Cape Coral; FL Posts: 30	Get yourself a set of these, Mustang MIL Eliminators at AmericanMuscle.com - Free Shipping! Plug them into your rear O2 sensors and then plug your harness back into them,your car will run normal again and you check engine light will go away as well,you're all done. Actually I just saw they don't have them anymore,they are getting hard to find for some reason,but there are about 50 places in the Mustang mags that carry them,you should be able to find some there. __________________ Quote from: Stevo on Yesterday at 12:30:41 Her ass has gone from 235's to 315's but thats another story. Last edited by Hybridbird : June 18th, 2008 at 03:52 PM.

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fastpoknee Newbie Join Date: Jul 2008 Posts: 13	2nd that

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