On my 95 eclipse,i decided to take it to the shop.They called and said my o2 sensor before the cat was gone....i have racing headers so i guess the shop that did the install before i got the car decided it didnt need a sensor.do i need the sensor?shop said the car was running rich
also my timning was off 2 ticks....3 would have bent the valves.I kinda thought the timing was off myself.
here is my question.
since the car would hesitate and backfire ...usually after it was warmed up....stall going down the road...and idled like poop....do you think the 02 is the culprit or the timing is more of the problem?
also,the car has aem cam gears on it.
Dealer wants $190 for a 02 sensor,shop says they cant find one anywhere any cheaper..I do not want to put on anything i dont need and esp at $200.
any suggestions is appreciated.

$54

http://www.sparkplugs.com/more_info.asp?AAIA=1314733&pid=1989

#1 Was your car throwing codes? If the O2 sensor was missing completely, that'd be a code and a major leak (Im unaware of any headers that don't have provisions for an O2 sensor) but you would have noticed a CEL first thing when you got the car back from having the headers installed. Also, I need a pro here, if your timing is off a tooth isn't that only 5-8 degrees, couldn't that be taken care of with your cam gears, they're adjustable right? I mean, I wouldn't allow it to go on to long, due entirely to princible, but it seems to me your problems could have been cured with two wrenchs, an O2 sensor, and a little time.

Also, you do need an O2 sensor, the car will not run properly without it, some people have realized 3mpg difference from just changing the O2 sensor.

Originally posted by Keith2172
#1 Was your car throwing codes? If the O2 sensor was missing completely, that'd be a code and a major leak (Im unaware of any headers that don't have provisions for an O2 sensor) but you would have noticed a CEL first thing when you got the car back from having the headers installed. Also, I need a pro here, if your timing is off a tooth isn't that only 5-8 degrees, couldn't that be taken care of with your cam gears, they're adjustable right? I mean, I wouldn't allow it to go on to long, due entirely to princible, but it seems to me your problems could have been cured with two wrenchs, an O2 sensor, and a little time. Also, you do need an O2 sensor, the car will not run properly without it, some people have realized 3mpg difference from just changing the O2 sensor.

thanks for the replies.
I was getting cels for the o2 among a few more that i have fixed.The headers were on the car when i bought it as were the cam gears.
I just bought a bosch 02 for $49 and took it to the shop.They are going to mount it so the 02 will read correctly.They are also going to fix the timing.Engine was replaced with a 60k mile engine and the timing belt and cam gears or all new.I think whoever did the work didnt know what the hell they were doing.This came from a tuning shop in atlanta but I will not post their name.
The guy at the shop said the 02 should get the car running right and the timing will put her in great shape.
Maybe after 4 months of worrying with it,my wife will have her car to drive..lol
and leave me alone about it...lmao
and next is custom interior....black and orange...hehe

the o2 sensor is as easy to replace or put in as a spark plug, actually i think its easier imo, you could have done that your self, as for the timing its a little harder but still not worth paying to be fixed unless you just really have no clue about engines, for real though if you could figure out how to open the hood the the o2 sensor should have been a piece of cake.

Originally posted by joeck76
the o2 sensor is as easy to replace or put in as a spark plug, actually i think its easier imo, you could have done that your self, as for the timing its a little harder but still not worth paying to be fixed unless you just really have no clue about engines, for real though if you could figure out how to open the hood the the o2 sensor should have been a piece of cake.

there was no place for the o2 to go,they have to make a place to mount it.I dont have the tools to make the hole for the new 02.

car was fixed by changing the ecu.That's what i thought to start with,should have done that first.saved myself alot of grief.

i just noticed u have -4 points. i didnt know that was possible.

Cam timing being off even 1 tooth, will idle like crap, but off idle will be just fine. 2 teeth off will really idle like crap, and off idle will be choppy as well. For reference, 1 tooth on the cam is approx 10 cam degrees, which is the adjustment limit for most aftermarket adjustable cam gears. If your car runs just fine now, at idle, then i'd say your timing is fine. If it still idles choppy with low vac at idle(10-14 hg's) then timing is off. A dead front o2 sensor will cause it to run rich all the time. The ECU will stay in open loop continuously. The engine shouldnt run bad like this, just give really bad gas miliage and run really rich, esp when fully warmed up.

car gets about 30 mpg.It has a lope to the idle still.I have to tune it and i think she will be fine.The ecu helped alot
the -4 on my feedback were some guys who didn't like what i had to say in some posts.I think they thought the were hot shit..lol