P0421 code

[littlemoule]

In short: Mental health, in long: I tend to spend some time in my car just sight seeing sometimes with engine on. Cat converter is not only for emissions/environment but also for yourself. Without cat, the car produces notorious amount of CO gas at all times compared to a car with a cat converter. In the right conditions, with wind blowing and my windows down sight seeing, gas can accumulate a bit towards me.

[7milesout]

In short: Mental health, in long: I tend to spend some time in my car just sight seeing sometimes with engine on. Cat converter is not only for emissions/environment but also for yourself. Without cat, the car produces notorious amount of CO gas at all times compared to a car with a cat converter. In the right conditions, with wind blowing and my windows down sight seeing, gas can accumulate a bit towards me.

2 things:

1. I didn't know you people up in Canada "reckoned." I thought that was limited to us in the SouthEast U.S.

2. I also own a 1972 Plymouth Scamp with 0 emissions equipment (and 0 muffling equipment too). Let's just say, I get exposure. Although, I have the son of a gun tuned to run back and forth through stoich as much as possible. The scant amount of hydrocarbons or CO you *might* breath from your LS is not going to be an issue, at all. That is, unless you are a person with some serious breathing issues then it might. On top of that, if we all realized how much exhaust we breathed from other cars while in traffic, you'd be alarmed (maybe). So I wouldn't be concerned about the exhaust from your own car, it will be small potatoes compared to what you're getting from heavy traffic areas. The only way to avoid it is to live rurally, and not go anywhere.

[Wallythacker]

2 things:

1. I didn't know you people up in Canada "reckoned." I thought that was limited to us in the SouthEast U.S.

2. I also own a 1972 Plymouth Scamp with 0 emissions equipment (and 0 muffling equipment too). Let's just say, I get exposure. Although, I have the son of a gun tuned to run back and forth through stoich as much as possible. The scant amount of hydrocarbons or CO you *might* breath from your LS is not going to be an issue, at all. That is, unless you are a person with some serious breathing issues then it might. On top of that, if we all realized how much exhaust we breathed from other cars while in traffic, you'd be alarmed (maybe). So I wouldn't be concerned about the exhaust from your own car, it will be small potatoes compared to what you're getting from heavy traffic areas. The only way to avoid it is to live rurally, and not go anywhere.

I recall the era when you were sitting in traffic and there were quite a few muscle cars around you the smell of raw gas was nauseating. I'm talking 1974-80 era when there were still plenty of 383+ - 454 cubic inch 4 bbl cars on the road. Those things were only 25% efficient at best, meaning 75% of the fuel became emissions. And we're talking about cars that got 8-10mpg when driven gently.

As a motorcycle rider in that era my lungs must have been screaming please stop! It really was a brutal time.

[7milesout]

My Scamp is 360 cubic inches, 4 barrel carb, tuned with a view of a wideband AFR sensor. So it is tuned well. Tuned for max hp, tuned for max mpg. Just the 'round town useless driving I do in it, it gets about 13.5 mpg. Cruising the interstate, maybe 17.5 mpg, but I only go 60 mph because it is screaming 3,000 rpm at 60 mph. I think it has a 3.55 gear and 14" wheels (24" diameter total), so those little skateboard wheels are turnin'! Fun car, but it loves gasoline, probably does better than most other 360's in both power and mpg. Since it was given to me, I've tuned it (no mechanical changes) to the point it is up about 65 hp.

But yeah, it can be smelled from a mile away.


On edit: I lied, I did put all new exhaust on it, including headers. And a new smaller cfm carb.

[littlemoule]

just a quick update. Same code appeared again and then disappeared. Just updating my fellow idiotic but smart friends. Starting to save up for a new catalytic converter so maybe in 2 months I will have it.

[Wallythacker]

My Scamp is 360 cubic inches, 4 barrel carb, tuned with a view of a wideband AFR sensor. So it is tuned well. Tuned for max hp, tuned for max mpg. Just the 'round town useless driving I do in it, it gets about 13.5 mpg. Cruising the interstate, maybe 17.5 mpg, but I only go 60 mph because it is screaming 3,000 rpm at 60 mph. I think it has a 3.55 gear and 14" wheels (24" diameter total), so those little skateboard wheels are turnin'! Fun car, but it loves gasoline, probably does better than most other 360's in both power and mpg. Since it was given to me, I've tuned it (no mechanical changes) to the point it is up about 65 hp.

But yeah, it can be smelled from a mile away.

On edit: I lied, I did put all new exhaust on it, including headers. And a new smaller cfm carb.

I forget. Was that a Carter carb on those? Were Carters all built with the larger bore secondary's or just some models? I liked them but I had so much experience with Holly (and Solex and Lucas and Mikuni and Tillotson and Walbro) there was no point to me trying to learn another.

[7milesout]

Wally - I'm not positive. It came to me with an Edelbrock, I learned that carb and stuck with the brand. Although I'm not happy with it. It has an off-idle lean stumble that irks me to no end. You can drive off aggressive no issue. But if you want to pull away in no particular rush, it lean stumbles after it consumes the pump shot.

I think the car came with a thermoquad. My understanding is the Edelbrock is more or less a thermoquad. There's no way a factory tuned car would stumble like this one does. Now, many drivers would not even notice the stumble. But I hardly watch the road for staring at the AFR gauge. And I watch it stumble and then I can feel it. Tis quite annoying. I don't know carburetors except Edelbrock. I want to try a Holley. I hear they're mo' bettuh. There's actually some highly tuneable Holleys, I forget the details. Seems like there's an aftermarket company that buys bulk Holley, and swaps out various parts to increase the tuneability. That's what I'd like to have. If I were retired, and had time to play with tuning a Holley day in and day out, that would be fun.

[Fummins]

I thought carters were usually similar to edelbrocks with similar sized primary and secondaries. The secondaries on an edelbrock are slightly larger. I've seen people install quadrajets in place of the plastic thermoquad, which I thought had considerably larger secondaries. I could look it up but that's almost like reading.

[7milesout]

You may be correct. I'm no expert on the history of carburetors. All I know is Edelbrocks (and their annoying lean stumble).

[littlemoule]

i have no idea what you guys are talking about lol