dan_c

hello

new to posting, so you might have seen my other ramblings...so now I have found the 944 specific forum (gong)..

Not experienced with mechanics really...but I couldn't help notice the awful clanging which sounded from my cat. So I ordered a new one from all-catalytic-converts.com .....they say it is built to OEM specs and bolt on...

so I never got a check-engine-light even with the clanging...is my o2 sensor dead..? and....the sensor was definitely not ever replaced as I have the service records..

I am hoping that the 02 sensor is the only thing causing my cat to blow out...when I take it apart i will try to inspect it...have never done this type of work before so i don't know how suscessful it will be...

My spark plugs are 15k old...but the car sat for a while, maybe a year or more before I bought it...I pulled one plug and it looked pretty good...but what do I know...
any help is appreciated...btw are bosche supers good plugs for 944S (wr7dc)..? if not what is better, what's the gap and how much torque...?

now I need a drink

pearldrum944

Is it just a rattling noise coming from the cat at certain RPMs?

dan_c

no...I wish it were...the sound, in addition to a rattle, is like bits of metal in a tin can....Tonight I tapped it with a rubber mallet and heard the sound of broken stuff inside...there is also a big dent and scrap marks directly underneath....I do remember a recent bump that I didn't like...but it's hard to tell ...the dent may be old...I'm really curious about the o2 sensor since I plan to replace it...

s928s

The noise you are hearing is the catalist itself has come loose. the catalist is kind of a ceramic porous brick that is mounted inside of a "coffee can". I can separate from its mount over time. some time hitting the casing will jar or loosen the catalist causing it to rattle. Doen't mean there is anything wrong with the motor or management system itself. The engine management or o-2 sensor would not notice the cat. issue because the sensor is reasing the gasses before the cat.. It would have to have a "monitor" sensor past the cat to motice and inefficencies with the cat....so in short, the catalist just probably came apart with age !! I would just replace the cat. or hollow the old one out if you do not have smog testing in your area .

..probably would not hurt to replace the 15 year old plugs though !!

pearldrum944

From what I hear, gutting the cat sounds extremely bad. If you want to get rid of it, most just weld in a straight piece of pipe. My exhaust got moved around a little when I did my clutch job about 3 weeks ago, it's rattling quite a bit. I'm going to try and replace it soon.

dan_c

hey thanks....I thought about the sensor thing and realized that too...it comes before the cat..

oh yeah..the plugs are 15,000 miles ....not years i wanted to try and index them without using any special spacers..but I figure I need a torque wrench or else I'll be guessing how much torque I have to play with....

Should I replace the o2 sensor just for the hell of it since I'll be there anyways and the universal only costs $46..? I read an article online which said it should be replaced every 40k miles.

s928s

thats a maint. call, although you may find it easier to replace it with the new cat. some times getting the old one out is a biatch...can't hurt

pearldrum944

Get the car warm before loosening the O2 sensor. Unless yours is loose it won't ever come out unless the ehaust pipe has expanded.

Bill L Seifert

Boy that sounds wierd. Let me get his straight, you had a bad Cat. replaced it and the new one went bad? I bought a 1987 944S last winter to make into a race car, it had 226,000 miles on it, and there is nothing wrong with the cat, and it looks original. I am going to take it off and throw it away, because you don't need one on a race car. Too bad you are not near Tennessee, cause I would give it to you.

Bill Seifert

1983 944 Race Car
1987 944S Race Car under const.