355 Thermocouple Question

Not having the 'middle' thermocouple in the muffler will not cause a CEL. Capristo exhausts do not have a provision for it. The 'middle' thermocouple is there to monitor a 'stuck open' condition of the bypass valve.

 

Are you sure? I have heard of folks wiring open their exhaust bypass valve and getting the CE light from the thermocouple getting too hot. So is the fix as simple as removing the thermocouple? I would think people would have done that long ago if it was the solution.

 

In addition if you wire the bypass valve open that adds another can of worms (than just removing the thermocouple). You will absolutely get a CEL with the bypass wired open with or without the thermocouple installed. On a 5.2 355 the cats & o2 sensors may not get the exhaust they need during low RPMs to monitor A/F ratio accurately. Instant CEL.

 

Gothspeed is absolutely correct. I too have the Capristo exhaust and I've got that thermocouple tied to the frame. A year and 2500 miles later, no CEL.

 

I will preface the conversation that the Capristo does have an exhaust valve (or valves depending on version).

 

A Thermalcouple being left out or an inoperative bypasss valve will cause a check engine light. It is however very difficult to meet the conditions required to get it to fail the test. Most of us will never be in WOT long enough to trigger the lamp. The Capristo that is missing the bung for the thermalcouple will typically set the light during our track events.

 

Yes they do integrate the bypass valve(s) depending on version................. but I thought we were talking about the non-existant 'provision' for the bypass valve THERMOCOUPLE..........

 

John, I have the same muffler installed on my car, I have also test pipes and it sounds great. a bit LOUD but great ... In addition it saves something close to 15 kg at the extreme rear of the car which is good also.