My first engine diy engine out

OK then if you hollow out the cats you will have a 'check engine' light issue. The O2 sensors after the cats are used to measure 'catalyst efficiency' or how well the catalytic convertor's are working. This ensures that the emissions remain within specs for the lifetime of the vehicle. Just as the pre-cat O2 sensors send information back to the ecu reporting on the previous combustion event which allows the ecu to make fuel trim modifications, the post-cat O2 sensors send information back to the ecu regarding the oxygen content in the after catalyst gases. The signal of the pre-cat O2 sensor ranges from approximately 100mv to 900mv in a typical zirconia sensor and this signal changes quit rapidly sometimes upwards of 15 times per second depending on a number of factors. The post-cat O2 sensor signal usually hovers around 450mv and is quit stable (meaning little change) with a properly functioning catalyst. In my experience you will get a catalyst efficiency code (usually a p0420)if the voltage fluctuates beyond about 350mv and 650 mv during the time that the catalyst monitor is run. This is usually at idle when the engine is warm and the vehicle is in closed loop operation. In other words if you hollow the cats out you will most likely get a check engine light.

However I need to ask the question, unless you are looking to run your vehicle on the track only why hollow out the cat's? In my experience catalytic convertor's present less impedance to exhaust flow than the muffler does. I of course don't have a ton of F-car experience but have done enough other performance work on other brands and for a vehicle driven on the street unless the owner is really serious we leave the stock cat's in place.

Just my 2 cents worth.

Jamie

 

No problem, happy to help. I am starting my own car today and will confirm that it has a Tubi exhaust and still retains the stock cats. Although I will be removing them to have a good look inside. Have fun.

 

Again? Now you are up 14-0 ....looking forward to the pics.

 

Ouch sorry to hear; I just heard of another local guy who had something similar. I would suspect timing being off, causing it to run too lean (high temp). Or I think I've heard that bad exhaust manifolds can also cause the lean condition and high temps...

 

I'd have the injectors checked too. You could have a partially clogged one causing a lean condition. There was another member that had his checked recently. You should be able to find the info with a search.

 

I'm assuming you had a valve guide issue?

 

I will definatly DIY the last one for you. Whooooohoooo!

 

One has to wonder what was on his mind at the time of posting.
I think that may be a PC picture equivelent of whats called a Freudian slip

 

The piping connections look like V-bands. Check this link and see if that's what they are.

http://images.google.com/images?q=v-band%20flange&um=1&ie=UTF-8&sa=N&hl=en&tab=wi

 

Normally, I would suggest "if it ain't broke, don't fix it", but, since you have it out, be thorough.

 

Is this the exhaust clamp you're looking for?

http://www.ricambiamerica.com/product_info.php?products_id=261264

 

Did you replace a 2.7 motor with a 5.2?