Could my catalitic converter be clogged? boost just keeps getting lower and lower

[damian9669]

The car ran very well for a little while.Then the car started to loose boost response and boost.I was making 10 psi and then it started to drop to 9.5
Then I was at 8psi.Now im at 6.5 psi. Could this be a sign of a bad catalitic converter.I have noticed that the exhaust has become a lot louder and I also have a few other symptoms as well.Bouncing idle,low idle sometimes,backfires when i let off the throttle.So im thinking exhaust restriction

[jake1.5]

if the converter is plugging you would loose power the higher the rpm you were at because pressure would build between the cat and your engine. what type of car is it, most imports you can unbolt the exhaust in front of the converter, the car will be loud as hell, and if it is OBDII it won't run very well because you eliminate the 2nd O2 sensor. That is one sure way to tell.

hope that helps

[HONDA GHANDI]

^ what he said, Its possible that your cat is going away but,

The secondary 02 sensor on a OBD-II car doesnt have any affect on hoe the car runs, it is merely a test sensor to determine cat efficiency. So if your car is OBD-II it would have set a P0420 code for bad cat.

[damian9669]

You know I think the car is obd 1.
The car is a 3rd gen rx7 and power does fall of as rpms climb.At redline boost falls off considerably.Would low end power be affected as well? would boost response also be affected?

[DiSekt]

Could be a boost leak?

[damian9669]

thats what I was thinking as well.Either a large boost leak somewhere or a clogged cat.The reason im suspecting the cat is because my airpump failed about a year ago and without it they say that the cat will eventually clogg up.

[damian9669]

I want to punch the cat out and see if it fixes my problem.But with 3rd gen rx7's doing so will uncork the engine too much.So if i were to spike in boost above say 10 or 12 psi boom there goes the engine.Otherwise I would have put on the nice ss midpipe i have laying around.

[doctorstupid]

A cracked wastegate flapper/turbine housing can cause boost to drop like that, though first thing I would do is check your intake for leaks.

[damian9669]

how would i go about checking for a cracked turbine housing? carb cleaner?

[doctorstupid]

Take it off? :p

[damian9669]

theres no other way besides removing the turbos? or can you take the turbine housing off without removing the turbos?

[WRX Harvey]

You can also remove the downpipe if the wastegate is integral. The flapper door and housing will be right there saying hi.

[damian9669]

I suppose thats a possibility.I really hope its not a damaged wastegate door.That would suck big time.

[doctorstupid]

There are several other things it could be, an old worn out wastegate actuator may not close fully or creep open a significant amount with exhaust pressure.

Although the easiest thing to check for is intake leaks, if that checks out I would investigate the wastegate and exhaust housing next.

[damian9669]

sounds like a plan doc.
I remember I was having precontroll issues before this came about.
The precontroll is in charge of pre spooling the second turbo in case you didnt know what it was.

[doctorstupid]

Oh, I just realized we're talking about an FD, there are a bunch of things it can be since that turbo setup is pretty complex...

Good luck!

[damian9669]

Yeah.LOL
Now you see the nightmare I have to deal with when it comes to the fd's sequential turbo system.Its very nice when it works correctly.But as it stands right now Ive had it work correctly for about 2 days out of the two years ive owned the car.Im going to need all the luck I can get.

[doctorstupid]

Yeah.... you have fun with that :p

[damian9669]

Gee thanx.LOL
Yeah its a pain in the ass.If I had the money the car would have a apex rx6 single that spools almost as fast.Full boost by 3200 rpms versus 3000 with the twins.But none of the bullshit I have to deal with the sequentials.

[4130]

I have a 1988 accord, I took it to the exhaust specialist and they told me that my catalitic conveter was plug. They told me after 50,000 miles the catalitic converter needed to be replace. So it depends how many miles you got in your car. If it has alot of miles you should get it check, they did not charge me for checking the catalitic converter. I believe your catalitic converter is plug because my car was acting like your car when it was plug. ;NutKick;