Cat Converter - HELP!!!!!

[tnSHOtime]

Hi everyone - Just got finished with a partial upper 60k service on my 1995 ATX, and had an unusual problem when everything was back together. The SHO now has an intermittent "pop" from the exhaust and a gush of air. Checked it out and the cat converter glows bright orange - have noticed a significant fuel odor from exhaust for quite a while, and fuel milage had dropped to approx 12.5 mpg. Believe the o2 sensor and cat converter are both bad - fpn lists converter at over $2100, auto zone lists a universal fit for 79.99. Any advice???? Any help or comments would be greatly appreciated.

Thanks

 

[Camarok]

well my buddy had that same prob on his suzuki sidekick, the cat was clogged. I don't know if it has anything to do with your 60k job, unless somehting got sucked/blown down to the cat clogging it. Chances are cats are clogged. IMO

 

[shobikes]

You can get a new Catco SS unit for under $300, or a Perf Plus or SHOShop hi-flow cat y-pipe for under $600. Do not get a stock replacement - it is crap. O2 sensors are $50 apiece from AutoZone. Are you throwing any codes?

 

[tnSHOtime]

throwing 13 - 31 - 33. Possible EGR problem???

 

[tnSHOtime]

OK

Talked to a friend of a friend who is a ford mechanic. He says I need a new DPFE sensor (which has caused the cat to clog up) a cat, and new o2 sensors, of course. What do you think???

 

[TYSHO]

DPFE?

 

[Mr Anonymous]

Uhh, you're reading the codes wrong. You actually got 111's all across.

The DPFE can't cause a cat to fail, and if this guy is really a Ford mechanic, I'd avoid whatever dealer he works for.

Your best bet for a replacement dual converter/y-pipe assembly is to find a good one used (try posting a WTB in the WTB section), or you can try FPS in GA for the PP aftermarket pipe for around $600. A universal cat will not direct fit to the y-pipe, and will cost tons in labor to make it fit. The Catco pipe mentioned above is only for MTX cars.

 

[Havok]

I had the same thing happen to my 95' ATX on the way home from purchase. Mine actually melted a hole in the front converter and also melted the inner cv-boot and caught the car on fire.

I took my y-pipe off, cut one side of the top heat shield on each converter and bent them out of the way. I then cut a rectangular hole in the top of each converter somwhere near the middle. Trough the holes I was able to completley gut both converters. I then cut a few rectangular pieces of sheet metal larger than the holes in the converter and used my mig to weld them in place.

I then tacked the heat shields back down. I also found that pieces of my conveter made its way down the exhaust. Instead of trying to get the pieces out down near the bends I just ordered a cat-back exhaust ( it was overdue for mufflers anyway ). Besides the cv-joint clean, repack and boot replacement the Oxs sensors were also replaced.

The actual cause turned out to be one bad plug wire and shorted high-tension leads inside the plug wells (they were full to the top with water). It caused it to dump raw gas into the exhaust that was ignited at the hot converter causing the meltdown. Had the exact same thing happen on my grand cherokee last year although it didnt cause a fire.

 

[MilTownSHO]

shobikes:
O2 sensors are $50 apiece from AutoZone.

Just paid like $38 a piece at Advance Auto

 

[shobikes]

SHOooo:
Uhh, you're reading the codes wrong. You actually got 111's all across.

He's saying that b/c the Gen II's had three-digit codes.

I've also heard of the Catco's fitting ATX's - for the $300 (which I can't really afford either) I'd figure a way to make the cheaper unit fit.

As far as what made the cat fail - sounds like very much too rich or raw fuel got down there somehow - did the new plug wires get installed correctly? Start with the simplest and most obvious, since it wasn't a problem prior to the service.

Good luck!

 

[shobote]

If no problems before the 60k, something may not be reconnected properly; a pop in the exhaust sounds like a cylinder misfiring (or firing when it's not supposed to might try checking plug wires for proper connections or maybe mixed up a couple when you did the re-connection ?
You (or a mechanic) can also quickly check cylinder temps with a handheld digital temp. reading tool that gives a direct temp readout on each cylinder when the engine is running by just pointing it at each one to locate the one that's not firing properly (it'll be colder). Hope that helps....

 

[tnSHOtime]

Thanks everyone for all the advise - looks like I need to do a little more diagnostic work.

 

[silversho89]

Do you know for sure if it's a plugged cat? If not do a vaccuum test. The vaccuum should be normal and then slowly start to drop as the cat is filled up with exhaust. thumb