[cory]

before I took my cat off, my check engine light had been on for over 6 months. the 2nd day I had my cat off it turned off, and has been off for 3 days now. I thought it would make the light come on?

 

[SSRage]

Huh, it might have been the check engine light was on cuz the cat was so stopped up that the computer sinced that something was wrong due to the reduced power and flow of the exhaust. A plugged up cat can affect a lot of stuff.

 

[cory]

thats what I was thinking, because the cat was making a horrible rattling sound before I took it off.

 

[cory]

will taking off my cat make the engine run rich?

 

[SSRage]

can't help you on that question. my diesel runs just fine without it. It shouldn't make a difference in my opinion because you don't have sensors behind the cat so the comp/motor won't know anything is different besides its breathing better. You might also pull your plugs and clean them, and pull your distributor cap as well and check the contacts and rotor for wear.

 

[94 SLT]

It shouldn't make a difference in my opinion because you don't have sensors behind the cat so the comp/motor won't know anything is different besides its breathing better.

Sorry but must correct you on this. The OBDII electronics moved into production in 1996 and with OBDII there is a pre-cat ox sensor and post-cat sensor. If there is no cat there then it sees a problem because there is no diff between the "in" and "out" sides of the cat. He needs a sim to plug the sensor line and "fake" the computer.

 

[cory]

but what does it mean if my check engine light turned off instead of on/staying on?

 

[SSRage]

well, here is a correction to your correction. my truck doesn't have sensors after the cat. i've checked repeatedly cuz I thought it was weird too. but im fixing to cut mine off and redo my whole exhaust. matter of fact my 97 F250 Powerstroke Diesel didn't have a sensor after the cat and it was flashing the check engine light. I took it to the dealer and paid them $160 for them to tell me that it was my cat clogged up and not my turbocharger going out. took the cat off and the power came back along with the gas mileage and everything is fine now. My friends gen II dak with the v6 didn't have a sensor after the cat and his truck was having the same probs as cory's and he removed his cat as well and it runs perfectly with no lights. cory in my opinion just drive the truck and don't worry about it. if you don't have any lights on then thats a good thing. like I originally said I think the light was on because your cat was so stopped up that it was causing other problems but the truck couldn't pinpoint which. so i would say consider the problem fixed and enjoy.

 

[94 SLT]

well, here is a correction to your correction. my truck doesn't have sensors after the cat. i've checked repeatedly cuz I thought it was weird too. but im fixing to cut mine off and redo my whole exhaust. matter of fact my 97 F250 Powerstroke Diesel didn't have a sensor after the cat and it was flashing the check engine light. I took it to the dealer and paid them $160 for them to tell me that it was my cat clogged up and not my turbocharger going out. took the cat off and the power came back along with the gas mileage and everything is fine now. My friends gen II dak with the v6 didn't have a sensor after the cat and his truck was having the same probs as cory's and he removed his cat as well and it runs perfectly with no lights. cory in my opinion just drive the truck and don't worry about it. if you don't have any lights on then thats a good thing. like I originally said I think the light was on because your cat was so stopped up that it was causing other problems but the truck couldn't pinpoint which. so i would say consider the problem fixed and enjoy.

What year was your friends gen II? My comment was referencing Magnum engines.....

 

[SSRage]

oh sorry :slap: . i think it was a 92 i think. he still has it and its got 280,xxx miles on it. uses about a quart of oil every 500 miles but runs good other than that.

 

[cory]

yeah thats what im thinking, as long as the light stays off im good.

 

[cory]

there is a sensor after that cat, why isnt it throwing a code?

 

[SSRage]

i have no idea why but hey... the light could have burned out too for that matter. sorry not much help.

 

[94 SLT]

i have no idea why but hey... the light could have burned out too for that matter. sorry not much help.

I second that.. check the bulb