Damn "Check Engine" Light...

[94_camaro_z28]

My damn car's check engine light comes on periodically especially on the interstate after about 30-45 min of driving. (Some days it doesn't come on at all). It'll stay on till the car's turned off and then, when its turned back on, no light. Like even after restarting it right away... I've had it tested at like autozone and they all say the cars fine. I heard from around it might have to do with my cat-less exaust. (Catback without the cat). Like some sensor for back pressure measurements or something. Can anyone explain this better to me or have the same problem? Thanks...

[fabolous24]

that is probably it. My friend has a '95 Trans AM with now cat and he is having the same problem. His car also doesnt seem to be running right because there is no backpressure, but he just ordered a high flow cat so ill let you know if that fixes his problem.

[fabolous24]

o and he also has longtubes bTW

[94_camaro_z28]

The thing thats so weird is that the car runs fine. iIt does have an after market exaust on it though (couldn't tell you the kind, bought the car a month ago as is). Just wondering if there's a fix or just deal with it...

[coindex]

This is more likely your problem. Your O2 sensor is sensing rich due to your catless catback system. I have the same problem sometimes, but what i did to rectify this was to increase my ignition output in turn burning a better fuel mixture so the o2 sensor recognizes a better burn. I have had to problems with my light now since i've changed my oem coil and wires to the ho accel performance coil and wire set

Im running a v6 with bosch platinum plugs, accel coil, 300+ wire set, advanced timing 10deg, performance distributyor and coil
I also put a 3" muffler system on my car, with a high performance muffler which also helps alot

barely no backpressure which the O2 sensor would recognize

[94_camaro_z28]

Does the hollow sounding rumble that sounds when i rev the motor (like showing off, you know how it is) have to do with the o2 sensors too? It sounds real strong when i'm feeding it some gas but when i let off it kinda grumbles to its idle. It this cause of those too and how might you fix that?

[Chevyracincamaro]

the stumbling down when you rev is excess fuel burning off in the system. basically the comp throws a bunch of fuel in as you rev it up and when you just cut the air out (release throttle) it creates a rich situation which makes the badass stumble in the exhaust sound...

[94_camaro_z28]

Do all Camaro's do that? cause i had a 3.4L 95 Camaro with a cat-back on it and i dont think it did. On the other hand it didnt sound nearly as burly as the Z does. In other words is it completely normal and ok or is something worn out?

[scott07422]

Originally Posted by coindex

This is more likely your problem. Your O2 sensor is sensing rich due to your catless catback system. I have the same problem sometimes, but what i did to rectify this was to increase my ignition output in turn burning a better fuel mixture so the o2 sensor recognizes a better burn. I have had to problems with my light now since i've changed my oem coil and wires to the ho accel performance coil and wire set

Im running a v6 with bosch platinum plugs, accel coil, 300+ wire set, advanced timing 10deg, performance distributyor and coil
I also put a 3" muffler system on my car, with a high performance muffler which also helps alot

barely no backpressure which the O2 sensor would recognize

i flip the air cover over now the check engine light comes on and off when i play with the heat ??

[twdz28]

its your egr valve, dont worry about it... if you really dont like the SES light have the AIR! and EGR! programed out of the computer...
MADZ28.com
or
PCMFORLESS.com