Community Forums

wseyler · 07-09-2016, 10:53 PM

I have a 2004 workhorse W22 chassis with the 8.1 liter engine. Yesterday, I had the misfortune of having a catalytic converter go bad. I cannot find a replacement anywhere. I would suspect that there must be an aftermarket solution to this, but I cannot find it. Anyone have any ideas of what to do?

Davel · 07-10-2016, 12:34 AM

There are high performance converters, such as these from Jeg's. Magnaflow OBD-II 49-State & Canada Universal Catalytic Converters | JEGS High Performance

They may reduce back pressure for a boost in performance, though it would be small.

Good Luck,
Dave

vettenuts · 07-10-2016, 07:49 AM

Is it plugged or just not meeting performance requirements? Do you have an emissions test on the RV in your state?

Replacement originals are available, but you will need to dig out your wallet: Catalytic Converter

Arch Hoagland · 07-10-2016, 03:00 PM

How do you know for sure that it is bad?

When I was having a low power problem one dealer said both my catalytic converters were bad.

Turned out to be a dirty MAF.

bill06447 · 07-10-2016, 06:46 PM

Is it like this one? http://www.irv2.com/forums/f22/exhau...ec-190692.html

vettenuts · 07-10-2016, 08:32 PM

Quote:

Originally Posted by bill06447

Is it like this one? http://www.irv2.com/forums/f22/exhau...ec-190692.html

No.

wseyler · 07-11-2016, 09:47 AM

Thanks for the replies everyone. I know that the Converter is bad because it almost caught the motorhome on fire. This is my parents RV, and I was following them. My father was barely able to do highway speeds, and I was noticing that there was a lot of heat being sent out of the exhaust (kind of like the wavy haze you see on hot pavement on a summer day). At one point, I thought I saw some orange hot sparks coming out. My father finally pulled over to the side of the road and when I got under it, I noticed that the rubber isolators were on fire. I grabbed the fire extinguisher and put it out. The muffler on the passenger side behind that converter is completely bowed out like one of those stovetop popcorn gets when it pops into the foil. The heat and chunks from the converter were pushed into the muffler and would have eventually melted a hole right through. We had it towed home ($750) and now need to repair it. Wow, Vettenuts, those are some pricey converters. We do have emissions test in our state (WA). At it's heart, it is still a Chevy 8.1 liter. I would suspect that Workhorse did not do anything to the engine that would prevent me from using a converter that was designed for an 8.1 liter Chevy. I guess I am just wondering, is there something special about the stock converters?

jcgribks · 07-11-2016, 01:54 PM

I just had an aftermarket one from Magnaflow installed when I changed over to headers.

vettenuts · 07-12-2016, 07:00 AM

Personally, if the converter is damaged I would first disconnect and core the converter, i.e., remove the honeycomb material so it is a hollow shell. Then use a flashlight and look into the mufflers to make sure pieces didn't break off and block the muffler. Try running with hollow converters first to make sure there are no other issues.

The actual cause might be the fuel mixture is messed up and it is dumping raw fuel into the converter, that will cause it to grossly overheat. Are there any codes or is the check engine light on? Any exhaust leaks? Also, clean the MAF because if it is dirty it will skew the mixture as well.

You should be able to get aftermarket converters for a lot less, but at least you know you can get the original if you need it.

Arch Hoagland · 07-12-2016, 04:17 PM

Quote:

Originally Posted by vettenuts

Personally, if the converter is damaged I would first disconnect and core the converter, i.e., remove the honeycomb material so it is a hollow shell. Then use a flashlight and look into the mufflers to make sure pieces didn't break off and block the muffler. Try running with hollow converters first to make sure there are no other issues.

The actual cause might be the fuel mixture is messed up and it is dumping raw fuel into the converter, that will cause it to grossly overheat. Are there any codes or is the check engine light on? Any exhaust leaks? Also, clean the MAF because if it is dirty it will skew the mixture as well.

You should be able to get aftermarket converters for a lot less, but at least you know you can get the original if you need it.

I second cleaning the MAF as that helps control the air to fuel mixture.
Has there ever been any Check Engine Lights in the past?

wseyler · 07-13-2016, 11:37 AM

We had both converters and mufflers replaced, but it is still not running exactly right. My worry is that the heat from the plugged converter may have damaged the cylinder heads. I may at least need a valve job. Cleaning the MAF sensor does make sense. Maybe that is causing the loss of power now. It also could have caused the original issue that led to the converter going bad. If the MAF sensor was not working properly and the induction system was dumping too much fuel, it could make it back to the converter and cause it to fail.

wseyler · 07-13-2016, 12:06 PM

Oh, and no, the check engine light has never come on.

Brazel's RV Performance · 07-13-2016, 09:45 PM

Get a scan tool on there that displays fuel trims and see where they are both at idle and under load. Also check MAF grams/second under wide open, should be able to hit 220-230+ g/s with a normally functioning MAF

wseyler · 07-13-2016, 10:21 PM

Thanks, Jon. I will put my scantool on it tomorrow. We had the converter and muffler replaced, but I am concerned with running the engine too much without figuring out why the converter failed in the first place. I am thinking a too rich fuel mixture or ignition problem, such as spark plugs or wires. I am going to dig into it all tomorrow. I think that it is a rarity that the converter just fails on its own. Especially since it only has 24,000 miles on it.