2003 Cat 3126e cold start backfire

[KKH]

Again, thanks for all the responses.

Cat, I appreciate the explanation of what the CAT ET is but is is way over my head. The result I got from the Cat dealer is probably my fault. I thought their computer would show some err codes and we would go from there. They are a good shop.
Since we didn't have another episode on the way back home from El Paso to Seattle, I plum forgot about it. Now we are making new plans for another trip.

Bigd9 mentioned spaying the shinny air bag can, I will give that a shot. Don't know what the life span is for the Holland/New Way air springs. The coach is a 2003 Winnebago Journey 34HD. They probably the original.

I recognize the noise Ray Chez1 mentioned, but this bang was a lot louder, more like a small explosion. It shook the entire coach.

[RayChez1]

Originally Posted by KKH

Again, thanks for all the responses.

Cat, I appreciate the explanation of what the CAT ET is but is is way over my head. The result I got from the Cat dealer is probably my fault. I thought their computer would show some err codes and we would go from there. They are a good shop.
Since we didn't have another episode on the way back home from El Paso to Seattle, I plum forgot about it. Now we are making new plans for another trip.

Bigd9 mentioned spaying the shinny air bag can, I will give that a shot. Don't know what the life span is for the Holland/New Way air springs. The coach is a 2003 Winnebago Journey 34HD. They probably the original.

I recognize the noise Ray Chez1 mentioned, but this bang was a lot louder, more like a small explosion. It shook the entire coach.

If it is not the Air Dryer popping then something is hanging up as the airbags inflate. Somebody mentioned the stabilizing bar or sway bar hanging up on some other chassis part. I know that Monaco had lots of problems with those, but I had never heard or seen that happen on a Freight liner chassis. And if an airbag starts to leak what happened to mine the spring brakes will start setting up and the air pressure will drop. That happened to me leaving TT resort in Las Vegas. And that is why I had it loaded up on a flatbed low boy and taken to Freight liner in North Las Vegas. I told them to change them all. On the road again and they done a fine job. So I bought my coach brand new in 2003. This gives you an idea how long the air bags last on a Freight liner chassis more or less.

[KKH]

I might have jumped the gun on this backfire in the muffler but it is still on the table. A little history here if it's not too boring. Right after we took position of the motorhome, I took it to a local Freightliner (40 miles away) for a wheel bearing evaluation. They were ok but the muffler hanger bracket was broken and needed to be replaced. So that was done. At the time of the loud bang, I assumed it came from muffler and this might have happened before. The noise came from around the muffler area, it shook the whole coach. I went under the coach with a flash light looking for any kind of damage. All looked ok. The rear drivers side air bag is right there but in front of the muffler.
We'll see.
Thanks to all.
KKH