F-Body Europe

I just came back from a 2-week deployment, and when I started my car, my service engine light came on. I know that I have a small exhaust leak where the CATS are. Could this leak, coupled with the colder weather cause the light to appear?

Put a small bead of rtv on the flanges to the cats and that'll cure that up if you do have a leak. I put it on there anyways even if the v clamps are supposed to be superior to anything else.

No
Your SES came on because of the longtubes place the cats too far down the exhaust system. That code is probably for cat inefficiency within the first minute of startup. The only cure is to buy O2 sims for the second set of oxygen sensors.

I have had the headers on for a few months now, and the light never came on. Now all of a sudden it is on. I have O2 sensors on the tubes now, so where do i put the O2 sims for the second set of oxygen sensors?
And what is a "bead of rtv"?

Ken
The cooler weather is triggering the light. It is taking your cats longer to light off or reach their optimum operating temp to burn hydrocarbons. This is what the second set of o2 sensors measures. With the O2 sims you simply unplug the rear set of o2s and plugg in the sims and zip tie the sims out of the way. Leave the rear o2s inplace but zip tie the ends out of the way.

A bead of silicone is a simply a single continuous layer of silicone aplied to the component you are trying to seal. Silicone adhesive comes in many colors and mixtures. You ill want the high temp silicone with copper . It is coppery color. It works very well but will burnout if temps go over 500 deg F.

Mine did the same thing. I just learned to not notice it..

Jack
you must be well discplined to the light. That light would annoy the hell out of me.

Me too. When my light kept coming on due to the faulty EGR valve, it drove me nuts until I just had to replace the valve. I guess that light keeps the GM Parts Department in the red.

Well there are all kinds of lights that I like.... BUD LIGHT... , RED LIGHT DISTRICT... , being LIGHT HEADED (DRUNK)... , but that damn SERVICE ENGINE SOON LIGHT is NOT one of them!!!

Anyways, I thought that maybe carbon build up could be a factor... so I went out on the autobahn, and cleaned out the carbon... and that damn light went off... go figure. Could be it got hot enough as Roy suggested. Anyways, its off until the next time it comes on... better not be anytime soon...