Cat. converter glowing red hot

[callbay]

2003 Ford Ranger 4 cyl 133,000 miles. Cat is glowing red after a 15 minute drive and then idling for a couple of minutes. Stayed red hot at idle. Even the pipe behind the Cat was glowing for a few inches.

The truck runs very rough at idle but at speed it runs fine.

Does this mean the Cat. is clogged up and needs to be replaced?

Is this what is probably causing the rough idle?

Thanks a ton!

 

[Lyman]

Sounds like you have a bad misfire and most likely dumping raw fuel into the CAT.

 

[oilmutt]

STOP! DO not drive the ranger,get this checked out first.Had this sane condition and and it caused a fire on the ground.

 

[Chris142]

Too much excess hydrocarbons are getting in the cat. You have an engine problem not a cat problem

 

[Colt45ws]

You have a misfire. The engine isnt running right, so the cat is running too hot as a result. Stop driving it and get it fixed. You probably have already damaged the converter.

 

[Merkava_4]

You have a bad misfire and your Service Engine Soon light should be flashing.

More than likely, one or more of the cylinders is not getting ignition spark.

Be prepared to replace the catalytic converter after you find the misfire.

 

[Trav]

It might also have a leaking injector, the cat is almost guaranteed to be toast now.

 

[Colt45ws]

Originally Posted By: Trav
It might also have a leaking injector, the cat is almost guaranteed to be toast now.

Yup, totally didn't think about that. For sure on the cat.
(Also, Happy Birfday!)

 

[Trav]

Thanks

 

[Gasbuggy]

May also have a bad plug wire, coil, spark plug. You should get a check engine light that will tell you the problem. If it just happened and there is no check engine light, the problem will still show in the scanner as a pending code.

 

[Trav]

Depending on what codes it has or doesn't, the next thing to look at is fuel trim.

 

[spk2000]

Like others have said too much fuel getting into it and causing the red glow. Been there and convertor was shot afterwards.

 

[Merkava_4]

I'm thinking I'd do a spark test first. If the catalytic converter is glowing red hot, that tells you there's plenty of fuel going to it that's not getting burned for some reason.

 

[01rangerxl]

Cat meltdowns are not uncommon on 3.0 Vulcans. If you have precats, those are done too. Just replace all of it.

The good thing is Walker direct fit replacements are pretty reasonably priced and work well, assuming they meet whatever requirements you need to meet in your area. My truck has a Walker y-pipe pre cat assembly that is over 2 years and 30K miles old and is doing fine. It's just louder than stock exhaust.

Do not buy a Magnaflow y-pipe if you have an automatic, it won't fit. The catalogs don't say that. The Walker looks ugly, but fits and works great.

Do you have a CEL? What is it?

Check your ignition coil and wires for any cracks. It happens at this age and could be contributing to the problem, but if the cats have been glowing, they are most likely going to need replacement regardless. You may have a contributing problem, but 3.0s that are worked hard are in turn hard on their cats. It's much more common on 3.0s than 4.0s to have to replace them.

Sorry, misread the OP. Not sure how common cat issues are on 2.3s, it's probably a cleaner burning engine than the Vulcan, but above may still apply.

 

[slacktide_bitog]

Any CEL codes? A misfire would cause it to blink. Most likely culprits are the plugs, coils, and/or wires. Bad injectors also cause misfire, but if it was the injector, then the fuel wouldn't be going through in the first place.

If you have a misfire code P0301/2/3/4, and the engine is coil-on-plug, try switching the coil on the bad cylinder with another coil. For example, if you have P0301, switch the #1 coil with #2, and clear the codes. If the misfire transfers to cylinder #2, the code will be P0302 instead, and you'll know that that coil is bad.

If that doesn't work, and/or if your engine isn't coil-on-plug, replace the spark plug on the misfiring cylinder only. See if the code comes back.

 

[DoubleWasp]

Searching for misfire under this condition is doing things completely backward.

A bad catalytic converter on its own can generate misfire in all cylinders on that bank.

If there is any record of misfire present, or detectable when driving, you need to remove the forward most oxygen sensor, clear the codes, and see if misfire is still generated.

If misfire still rears its ugly head, then you start diagnosing the misfire.

Once the misfire is resolved, replace the cat.

If you have no misfire codes, and no detectable misfire, then your cat has simply failed like so many other Ford catalytic converters do. Ford makes some of the worst of them by far.

 

[Trav]

Originally Posted By: slacktide_bitog
but if it was the injector, then the fuel wouldn't be going through in the first place.

Injectors can leak and still be functioning.

 

[eljefino]

I had a 94 B4000 and its fuel pressure regulator had a shot diaphragm. Chris142 figure it out from 3000 miles away! Raw fuel was getting sucked through the vacuum line and you could practically see it shooting out the exhaust pipe.

Under load there was less vacuum and more desire for fuel anyway so it wasn't as bad. But idling was a bad scene!

The diagnosis is to run it with the FPR vacuum line plugged.

 

[andyd]

AMC 360 V8 with a weak coil