1990 240SX Burned Air Filter

[SullivanRacing06]

block off the tube that runs from your egr to the air box between your inspections and see if the airfilter still gets burnt, if so then idk wtf is wrong with your car, if it stops then its either you egr sticking open or your cat is clogged

[dferraro]

To All: I took the AIG apart over the weekend. It was completely clogged. I cleaned and polished it to remove all of the soot. I also flipped the air filter around to get a clean end. I will run it this way for a week to see what happens. I will keep the thread posted with the results. Thanks

[dferraro]

To All: I checked the Air Filter; it is already showing signs of condensation & charring. At this point, I guess that I am looking at replacing the Cat. Has anybody ever replaced one? Do you think that someone with average mechanical skills and tools could do it? I also discovered a hairline crack in the Radiator. Does anybody have any thoughts on Bar's Leaks Liquid Radiator Stop Leak? Does it really work or am I wasting my money? Thanks

[Koshin]

dewd, just replace your cat....hopefully this fixes your problem, they have been telling you that for a month

[SullivanRacing06]

dewd, just replace your cat....hopefully this fixes your problem, they have been telling you that for a month

lmfao!

if you dont have emission tests then delete the cat, or replace, just get allot of pb blaster!

[dferraro]

NY does have emissions inspections so I need it. Understand that the following questions are because I'm trying to understand how things work. My emissions inspections results have been practically the same since I got the car. Granted they go up a little each year, but not much. I've had this problem for a few years now. If the Cat is bad shouldn't I have had problems passing the emissions tests, wouldn't the test results have shown a big change? What would cause the Cat to fail, the O2 sensor? From what I 've been able to find, it seems like a Cat failing by itself is very rare. Something usually causes it to fail and unless that something is fixed the new Cat will fail as well or so other sites have said. Thanks

[ZOMG.SR20]

Cats generally meow when there full

but anywho the Cats lose there effectivness around 100k and need to be replaced

[dferraro]

Does anybody have any thoughts on Cat mfgrs? Catco, Eastern Bosal, etc. Should the Oxygen Sensor also be replaced? Has anybody ever replaced the Cat? What am I getting into? Is it worth it to let a shop do it? Thanks

[BearTrap]

The cat will probably be rusted on both sides of the flanges that attach to your header and then the backside of your exhaust. Having said that, good luck on getting the bolts unloose to take the cat out. If the system is rust free (which I doubt), replacing the cat is a very simple bolt on.

Your best bet (since it will be rusted) is to take it to a shop, have them cut it out and weld on new flanges to bolt in or weld on a new cat. FYI, you wont find a "high-flow" cat at your local Meineke, so if you're concerned with that, order online with Catco, Random Tech, etc.

Is the o2 original? It couldn't hurt the situation, and it's only $30 bucks.

[IanS]

Its not burning per say, its soot build up, most likely from the AIV system backing up. I would test your AIV pump to see if it has failed, it should have a one way valve built it.

[dferraro]

I had taken the AIV apart and cleaned it. It was completely caked. There are some reed valves that I think are supposed to prevent the backflow. Can the Cat be so clogged that the backflo is forcing the reed valves open yet enough exhaust passes thru the Cat for the car to pass the emissions test?

[dferraro]

I just got off the phone with a Cat distributor (www.discountconverter.com) that I was going to use for the new Cat and Oxygen sensor. Before they would sell me the Cat they wanted to know why I thought that I needed one. I gave them the story from the burned air filter thru the cleaning of the AIV to the reburning of the air filter. They asked if I had any issues with the A/T shifting. When I said no, they stated that the Cat could not be clogged. They said that if air could not pass thru the Cat, the A/T could not shift properly or at all. I have no problems driving the car at city or highway speeds. I can feel the shifting as well as see it on the tach. They felt that it was still an AIV issue. Does anybody have any thoughts or comments on their take on the problem? I am confused again. Thanks