Code 31 tripped by clogged cat?

Throws

Active member
More fun from PO neglect...

The other day while driving home on the expressway, I tried passing a semi and felt the engine stumble and flash a CEL. (I don't think I was WOT, more like 3/4). I get home and pull the code, 31. Now, in chasing a low boost issue I'd cleaned up a fair amount of things (new actuator, new solenoid, new vac hoses, new relays, new AFPR, new Walbro). The only thing that I haven't done in that whole process is the cat. I'm pretty sure it's the original, and with 150k on the clock I'm concerned its clogging/bad/expired. It's also got leaky valve seals, so I'm sure that's contributed over the years.

SOTP: It's always felt a little weak on the top end. If I were to floor it, it's kinda got a feeling of malaise to it.... bland, uninspired. I'm making full boost (according to mechanical gauge) after who-know-how-long-or-how-many-years of the Ty running crippled @8psi.

Here's some pics of the cat: (looks like something is causing exhaust to rush past the ubolt?)

img2332dn.jpg


img2348b.jpg


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img2334cv.jpg
 

ItsMyTy

Life is beter at 25 PSI
Re: Code 31 tripped by clogged cat?

the pics really don't show anything abnormal

three ways to check for clogged cat:

testing exhaust backpressure with a gauge that connects where the o2sensor is

removing the o2sensor and driving it to see if it has more power (indicating a clogged cat and high backpressure)

hook a vacuum gauge to intake, check reading at idle and then at 2500rpm. if vacuum drops (closer to 0) at higher RPM it usually indicates an exhaust restriction


however i'd be careful with test #2 on a syty, the hot exhaust gas could melt something underhood
 

Throws

Active member
Re: Code 31 tripped by clogged cat?

...hook a vacuum gauge to intake, check reading at idle and then at 2500rpm. if vacuum drops (closer to 0) at higher RPM it usually indicates an exhaust restriction...

Well.. I mean, it hit zero as RPMs go up, but I'm still seeing boost (builds to 14~ish then drops dow to about 11~ish)

-P
 
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