hey so I just got new Catback installed at "Exhaust Pros" and now my service engine soon light is on and the fans kick in all the time. The fans don't usually come on until near red (220 or whatever the normal is) but now they turn on when the car is at running temperature and at the same time the service engine soon light comes on. Also when the fans go off...so does the light. I think its the 02 sensor that was messed up/removed. But if anyones knows whats up....let me know...and also please tell me how to fix it. Thanks

 

have it scanned for trouble codes and let us know what comes up.

 

i dont think 94 had rear o2s so it should affect anything with the catback,i think its just a coincidence that this is happening, and its really something else

 

the "service engine soon" is on...which means that it wont bring up any trouble codes...the only time you would get a trouble code is if the "check gauges" light is on

Also I think there is a "Rear 02 sensor" because I have seen them for sale...thats why I thought thats what the problem was, only thing is I don't know how rear it is...but again I'm not sure

 

you are completely wrong.If the SES light is on, it can be scanned for codes.When the check gauges light is on,its letting you know you should check the oil,coolant temp or voltage gauges.Im not positive as to when rear o2 came into effect with 4th gen f-bodies.

 

if the ses light has been on repeatedly then u will have trouble codes. im not sure were u heard that ses warnings will not trigger a trouble code but u are wrong. most times a check gadge light will not trigger a trouble code. ali knows his stuff so listen to him. the 02 sensors on an 94 are up by the motor on the exhaust pipe just after it comes off the manifold. one on each side.

 

well my apologies, I was told by 2 people from a local shop that you need the "check gauges" for codes...guess im not going back there ever again :S again....sorry....I'll take it somewhere else and have it checked and let you know what happens.

Again, sorry...I was misinformed

 

My 95 Z only has the 2 front O2's if that helps any with timeline

 

Rear O2 sensors (downstream sensors) were put in all cars in 1996 when the Feds mandated the switch to OBDII.

Deprnding on the trouble code, the fans may go on when the check engine light is lit. This is done to protect the engine.
If the check gages light goes on, it means just that. Check the gages as something is out of normal, such as temp, oil pressure, etc. If the engine overheats the check gage light may come on, and the fans should also come on due to high temp.

 

hay guys. dont let the day end without voting for your choise of the july rotm rides. lets get some votes in.