So I figured out all of my coolant leaks, and ecu codes. But when I went to start my car again today, my dp and exhaust manifold once again glowed orange. It seemed to start glowing orange on the downpipe side, i have an HKS dp, so the top flange is mild steel, it started on the main cat side, and seemed to be traveling twards the mani. Would that hint to a clogged cat?

Well I thought it pointed to a clogged cat, so tonight I pulled it off, and looked in at it. It seemed to be in pretty good shape actually. I dont really know what im looking for though. Also, I blew air out of my air compressor through it, and it seemed to go right through.

So, my questions are....How to inspect a cat properly, and just to see if it is a clogged main cat, could I just start and idle my car with out the main cat on? I wont be driving it at all, because it would be very very loud, and it woud cause all sorts of boost issues. Im just wondering if theres something im over looking that this would cause a problem with.

 

mods? that would help everyone determine what's goin on with your car. i'm calling either clogged cat or running too ritch. is the MAP sensor unplugged? details, details, details man.

when the cat went on my brother's '89 Merkur Scorpio (went at about 95k, 2.9L V6, 4speed auto) the car wouldn't rev worth ****, had no power, and couldn't get past 25 mph because of all the backpressure. we ripped it off, drove to my grandpa's house, open headers and all, cut the top of the cat off, pulled out all the catalyst, and welded the top back on. has ran beautifully since, had the exhaust replaced at Midas, and they didn't even realize that the cat was hollow.

 

sounds like the cat is having to work too hard. you've probably got a serious misfire dumping raw fuel into the exhaust.

 

Im pretty sure my cat is clogged. I just need to know if its alright to run the engine straight off the downpipe, or will the lack of backpressure hurt something? Im not going to be driving it, just let it idle.

Mods: larger street port, pettit unlimited ecu, apexi power intakes, hks dp, hks catback, light weight flywheel, act s/s with extreme pressure plate....the list goes on, but thats the major ones.

Oh yea, Im positive all of the vacuum lines are hooked up and are in the right posittions because I just did the silicon vac job, and ive had the uim off many times and ive checked.

 

you do not need backpressure after the turbos it is most important for the life of you engine to have little or no back pressure. ( the easier it flows the better your car will run)

oh yeah one more thing if you do have a clogged cat DO NOT RUN THE CAR!! this can cause severe damage to you engine.