Check Engine with mods

[Master]

hey guys, wondering if you can suggest a fix for the following:
After doing the heads, cams, valves, Kooks complete system, I got 1500 miles on the car over 10 days and THEN the check engine light came on. The diagnostics say "Cat Sys Efficiency below threshold (both banks)". Lists all of the possible causes, which I know, of course.
Any idea if this is normal with the Kooks complete system? Shouldn't it have registered within the first day or so? Is there a simple fix?
Love to get some feedback. fortunately, the code seems not to have put the car into any sort of "safe" mode. Still runs great with excellent mileage.
Be great to hear from some of you experienced fellows.
All the best,
- D

[O's Fan Rich]

I'll give it a try...
Do you have an aftermarket tune? If so it removes one set of O2 sensors to help with the Ck light.
After doing the X pipe, mine was on. I removed the negative battery cable for 30 minutes and it has not been back since.

[Marauderjack]

You're probably just too rich and the cats are carboned up!! An aftermarket tune or dyno tune would probably fix 'er up!!:beer:

Marauderjack:burnout:

[Master]

Thanks for the tips. I will try the battery solution to see if that helps. I will also try to save my pennies for an XCalII as I know its running rich at partial throttle. The main mods pretty uch wiped out the mod-fund for now. Would love to have the 410s and a tune all together.
Thanks again guys,
-David

[KillJoy]

so earlyKind of off topic, but, why did you go for Heads and Cams? It's kind of a pricey route for the results.

KillJoy

[Joe Walsh]

If the 'MIL' light comes on again, a cheap cure is to install a set of 'MIL' eliminators on the rear O2 sensors.
I put a set on my rear O2 sensors after a complete Kook's system install without a 'tune'....I've never had a problem with a 'MIL' or a code.
They are @ $59.99 per set from Dallas Mustang Parts, and simply plug in between the O2 sensor and the wiring harness.

[Master]

The contour boys used to use th MIL eliminators. I'll keep thi one in my back pocket as well. AS for why I went this route? We do the heads here in house, therefore, no monetary cost. The Ford Cam Kit came from a Florida E-Bayer, so more savings there. The Kooks, of course, was a no-brainer. If I'd had the money, the delete tips would have been on the list as well. I went from 242 rwhp to 304 rwhp. Thats a lot of ponies for 4k US. Now, when I add the Trilogy (within two years, if they are still available), I should easily see 450 rwhp. Of course, by that point, I'll want to beeef up the internals, which means I may as well go for the big-bore kit, which means a 500 rwhp car isn't out of the question.
All just part of my master plan ;)
Thanks much for the tips!
- David

[Paul T. Casey]

David, a man with a plan. One thing I didn't see mentioned here yet, did you get the rear O2 sensors wet? Sometimes I get a check engine light after a car wash. First time it happened, I read the codes, did the battery disconnect, and it went away. Two more times and the common denominator was the car wash. Kooks system must somehow expose them. Still, wouldn't trade the Kooks for the world.

[Master]

Now there is an interesting thought. I guess when I try the battery solution, I'll have to keep a close eye on the weather as well as the car washes. You could be right. I agree about not wanting to give up the Kooks. Beautiful system. The Magnaflows, however, may not last. They are a bit raucus for my taste.