Been making a trip to Dallas every 5-6 days the past few weeks for my wife to see a specialist. Was consistently getting 24.5-25 mpg until coming back on the trip last week and it dropped to just under 23. Rolled into Ft. Smith, Ar. and the service engine light came on. Got home here in MO. and pulled codes and it said the catalytic converter was not functioning properly. Put a new one on and headed back to Dallas yesterday and got 26.5 going and 26.3 coming back. The best it has ever gotten since I've owned it. Was a little surprised to get an increase. Same road, route and driving speed, 70-74 mph.

Anyone else had this experience? Not complaining mind you, just asking.

Oh, the converter failure was a loose core. I had been hearing an intermittent rattle under the car and had the dealer look to see what they could find during the last service but they couldn't find anything loose.

25mpg? I run my 80+ 400 miles earlier this year and averages 38mpg? It actually sounds way rich.

Gurus will chime in soon though.

SD

I am actually talking about my car. Didn't even know the bike had a catalytic converter.

I think the california models do

Tug wrote:
I think the california models do

That's news to me, and I'm a CA native. Maybe the latest models do, but to the best of my knowledge, there's no enforcement that I know of, because everyone still puts after market pipes, sans cats on, all the time.

Hi preacher

check your engine cooling system real good. If you have any amount, even a small water and antifreeze leak into an engine cylinder it will pass through with the exhaust and damage the converter. It clogs it up and raises the enternal temperature which could burn it out. It can also damage your engine with the excessive heat build up on that cylinder bank. You may get the converter failure first if you have a head gasket leak in the past and then start having other heat related problems. Not saying this is your problem but I have seen it before. Seen this mainly on General Motors vehicles.

Greg

Thanks for the heads up. I know these Northstar engines are famous for head gasket failures. As are all aluminum engines I have had any experience with. Make sure you don't ever overheat and the chances of a failure go way down but still a definite possibility. If I didn't like the power these engines make and the economy they have to go along with it I would drive something else but for the ride and drive they can't be beat in my book. I was just surprised to pick up about 1.5 - 2 MPG just by changing the converter out. Best mileage this car has gotten since I have owned it.

I just had the cooling system pressurized last week to make sure it was ready for winter but I had the converter problem well before that as I heard it rattling for over a month now. When I took it off the front core was loose and rattling around inside it. Back half was still stable. Glad it finally showed up and threw a code before it broke up and went into the muffler. Would have been even more expensive.

Never know what the newer models have HDs have Cats on them. Can't ever be certain on the requirements for sale in Cali.

SD

Cats suk, I cut them off of every vehicle I've ever owned!!!

I've had a few stop up on me, I usually gut them out and put them back on so when there checked for they see one.