Plugged cats? Glowing red hot

[Explorin'VA]

I was driving a few weeks back when the truck started to misfire and ping suddenly. It went way down on power and the truck was very sluggish. Replacing the spark plugs and wires fixed the misfire, but the truck still has an extreme popping sound, like a backfire inside the cats every time I press the gas peddle. The trucks idles fine but has no power when I drive it and after a few minutes of driving the rear cat gets red hot.

Should I remove the cat and see if that is actually the problem? Or is there anything else that would cause this? Thanks

 

[natenkiki2004]

I believe that's an indication of running lean. There may be an underlying issue that is still causing poor performance and thus hurting the cats.

 

[Explorin'VA]

I have had issues with an open spout circuit. It ran super rough. Took it to a garage and they grounded the spout wire and remove the plastic spout connector. I've been driving it like that ever since. It drives the same with the spout connector in or out. I think this means there's no spark advance which could be why it's running lean.

 

[FR-425]

You need a new ICM and new cat's

(the spout connector is NOT the one near the OBD connector) that is the Octane adjust.. The spout is up front with the ICM.

The spout is used to verify base timing. When removed there will be no electronic spark advance, so that the base advance of 10* BTDC can be checked with a timing light.. this is a fixed and non adjustable preset of the ICM.
An off reading would indicate a bad crankshaft position sensor and/or a bad ICM.

The octane adjust removes 3* from the advance curve when removed.

 

[2stroke]

Cats glow when you dump raw gas on them. It usually means you are flooding the engine with gas, but not always. Also, just because your cats got red hot does not mean the catalyst melted. If you continue to drive it, the cats will melt, or worse. Check your oil, and smell it ASAP. If it's over full or smells of gas do not start the engine. It will be the end of your rod bearings.

 

[malohnes]

Also sounds like your plug wires are still not in correct sequence.

 

[Explorin'VA]

You need a new ICM and new cat's

(the spout connector is NOT the one near the OBD connector) that is the Octane adjust.. The spout is up front with the ICM.

An off reading would indicate a bad crankshaft position sensor and/or a bad ICM.

That would mean the connector the mechanic removed was the octane adjust :scratch:

I recently replaced the crankshaft position sensor but I'll try changing the ICM after I check the oil and firing order.

 

[FR-425]

Pull the cats and have look.. it's common for the front cat to crumble and plug up the rear one.

 

[shucker1]

Perhaps a simple idea.

Connect a vacuum gauge to the intake and run the engine or drive the vehicle till the cats do their trick.

Very low vacuum at idle after the engine is hot would indicate a restriction in the exhaust system.

 

[Explorin'VA]

I also have noticed that the DPFE air hoses keep blowing off when I try to drive it.

 

[shucker1]

Lot's of evidence here suggest plugged cats.

Sounds logical Mr. Spock.

 

[Explorin'VA]

With the cats removed I'm still getting the same backfire when on the gas.

 

[shucker1]

If the cats are totally out with nothing connected it doesn't surprise me.

You need something in there to keep some type of back pressure on the exhaust system.

Without cats, the O2 sensor is probably freaking the computer out try to figure out what is going on.

Did you happen to try the vacuum gauge first?

 

[Explorin'VA]

Sorry to send yall on a wild goose chase for what could have been wrong. I simply had the firing order wrong. No more miss

 

[FR-425]

 

[FR-425]

Replacing the spark plugs and wires fixed the misfire,

 

[Explorin'VA]

The old wires had been burned by the exhaust. At least one cylinder was dead. Even after replacing the wires in the wrong order the truck seemed to run better. Just had a terrible backfire until i fixed the firing order.

 

[FR-425]

just yank'n your chain

 

[shucker1]

Good job!

I'll bet you won't make the same mistake twice.

No worries, that's why we are here.

 

[Explorin'VA]

I appreciate the help. Always learning something here.