Check engine light came on since work done

Discussion in '2007 - 2014 Shelby GT500 Tech' started by bottler1, Jun 19, 2010.


  1. bottler1

    bottler1 New Member

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    Hi all, got an 07 gt500 .had the ford shop put on ffrp kit for handling=great.
    problem= the shop did all the work putting on KR exhaust,drive shaft 900hp,upgraded super charger to 605hp,cobra jet throttlebody,ford racing complete intake,
    after all this and about 2 hours of driving my check engine lite came on so i took it back to ford and they told me that I wrecked 1 side of the cat?.
    anybody have a clue as to why i could riun an cat after spending 15k then only 2 hours of driving, ford wants to install new cats (my cost) this is not right.
    the Shelby i bought new in early 07 in Tunsten Great ride etc.:thanks
  2. bdcardinal

    bdcardinal tree hugger

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    how many miles were on the car when you bought it? What were the condition of the catalyst assemblies when you bought it? Were the parts purchased from the dealer that did the install work or did you carry them in?
  3. Lifter583

    Lifter583 New Member

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    I installed a Brenspeed Stage 2 performance package that bumped my 08 Gt500 to 547 rwhp (approx 645 crank)...I had a couple of fouled plugs before and it appears it allowed enough fuel to go to the cats to burn them...last week at full boost(13.5 lbs) I had dust and ceramic granuals blowing out the exhaust... It turns out I had only about 1/4 flow through them...I now installed MRT high flow cats with an H-pipe...runs great! Just trash those stock things and get a high flow set up...( I just turn over 3600 miles) I have to say 15K sounds steep to get 605 HP...
  4. socalwrench

    socalwrench New Member

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    It is possible that the cat. could be damaged and clogged. The honeycomb inside is more delicate than you'd think. A little extra heat and they crack. The downstream O2 sensor sees the change and trips the light. That usually occurs before an engine misfire; which would also trip the light.

    Like Lifter583 said, just swap out the factory units for some high flow units, and monitor you're fuel mixture and boost levels (if you can).

    One last thing- it's been my experience that cats are good for about 90k on a STOCK vehicle. You didn't say how many miles were on the car, so I'm just throwing it out there. I would try to contact Shelby American to find out if they sell any high flow exhaust parts.

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