How can I check if a cat is clogged?

646 Views 9 Replies 8 Participants Last post by 220ftlbAndGROWING, Feb 5, 2004

Ganchi

Discussion Starter · Feb 8, 2002

......or can the dealer do this without removing my exhaust?

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Re: How can I check if a cat is clogged? (Ganchi)

Ganchi, you missed me by about a month, i coulda had a look for you.
look for flow rate firstly. if you have an egt gauge that would help.
sportech can check it out for you as well.
when you gonna upgrade to a real exhaust?
if u need me to bring one down when i go back in july we can talk.

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Magnaflow.CA

· #3 · Feb 8, 2002

Re: How can I check if a cat is clogged? (Ganchi)

Ganchi.....a clogged converter creates an enormous increase in backpressure and is often confused with a slipping clutch, the performance feels the same, you step on the gas, and after some hesitation, the car goes.... Removing and physically inspecting the cat is a good check , but you will only be able to see if the visble part of the ceramic substrate is clogged...A simple test that can be done is a backpressure test....a small test hole is drilled pre and post catalyst and a backpressure gauge inserted to measure and compare the two readings....I'm sure someone can perform this test for you....If your converter is contaminated or melted, make sure you have a professional who knows your vehicle inspect and determine the cause of failure...

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chris86vw

· #4 · Feb 8, 2002

Re: How can I check if a cat is clogged? (Magnaflow.CA)

not sure what kind of cat you have in SA, but in the US they are metal matrix, should be the same there. MEtal matrix cats very rarely hve problems, and can even fool the untrained eye to think there is actually is a problem
chris
[email protected]

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Project20v

· #5 · Feb 8, 2002

Re: How can I check if a cat is clogged? (Ganchi)

I you happen to own a infared temp gun you can point and shoot before and after the cat to look for discrepancy's.

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Ganchi

Discussion Starter · #6 · Feb 8, 2002

Re: How can I check if a cat is clogged? (AxeAngel)

Thanx 4 all the replies. The thing is, we have pretty bad quality fuel here in S.A. We also have leaded fuel, I heard this kills the cat.
Axe, first I need a decent chip. Pitty nobody in S.A. can chip the 1.8T without surging.

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27psiBoom

· #7 · Feb 5, 2004

Re: How can I check if a cat is clogged? (Project20v)

What should the delta be between pre and post cat temps?, my flex joint is broken but looks like a lot of aire wants to come out before the cat from holes on the broken flex joint , maybe it's just me

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27psiBoom

· #8 · Feb 5, 2004

Re: How can I check if a cat is clogged? (27psiBoom)

I got a EGT gauge but it's bolted on the DP very near from the flange up top, how do I know if the temps are too high I see 950f crousing at 2500-3000rpms, 1150F at 4000rpms and almost 1450F at high speeds.

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inflatin

· #9 · Feb 5, 2004

Re: How can I check if a cat is clogged? (Ganchi)

Quote, originally posted by Ganchi »

Thanx 4 all the replies. The thing is, we have pretty bad quality fuel here in S.A. We also have leaded fuel, I heard this kills the cat.

If you use leaded fuel, you might as well run catless. I wonder what kind of octane rating your fuel has, since lead significantly boosts octane levels (but, clogs cats and puts out a ton of smog.)

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220ftlbAndGROWING

· #10 · Feb 5, 2004

Re: How can I check if a cat is clogged? (inflatin)

When I drove down to Central America I removed my cat for fear of poor fuel, ( I had heard it was inconsistent and damaging to my cat ) I used a straight pipe instead. Ironically later my truck was stolen and the cat. as well as most everything else was gone. Regarding VW's - my aftermarket highflow cat. ( and I think the stock one ) are fairly easy to remove. Look down the cat with a light, coming in the other end and you should see a honey comb structure ( actually a square matrix ) - square tiny tubes that run parallel with the cat. If its clogged - these will be fuzzy (with deposits ), if not it should be fine. Remember if you're concerned because the octane rating is low - that doesn't mean the fuel is poor - it simply means that it burns faster - that's right. A higher octane fuel takes longer to burn - thus allowing an increase in timing - the goal being - complete combustion 10 degrees beyond TDC. So if it's just lower octane you're dealing with, I wouldn't worry. If it's dirty gas - your cat. might get clogged.
Cheers

Modified by 220ftlbAndGROWING at 3:07 AM 2-5-2004

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