Seafoam for a Cat Converter?

I have just started down a rabbit hole of trying to get some better mileage out of my Gen II with 217K on the ODO. It all started with an engine code "Engine fail to start" (P0A0F I think). I looked around at things I could do myself before bringing it in to Toyota. I trust my mech, but he is not a Prius expert. So the first things I did were clean the throttle body and the MAF (since the filter was off anyway). The TB was filthy. I did not spray anything directly into the TB. I brushed and wiped it with TB cleaner. I cleaned the MAF with MAF cleaner. Once again, not while installed. Let dry. After doing this and cleaning the code, I did notice that the car ran a little rough for a few miles, but the slight stalling stopped. The next day I get a Cat converter code. Thought that was a little coincidental. Brought it to my mech and he recommended a bottle of seafoam in the tank every time I fill up just to see if there was any chance it could do the trick. I went ahead and did it this once and came home and researched it. Here too. there are the obvious pros and cons, but no one has talked about actually putting it directly into the fuel intake on a Prius like a lot of the YouTube videos I see. Nothing I have read or heard, even from Sefoam themselves say that it would harm the engine. Could I just take the filter off and spray it down the throttle body? Is there a better place to do it? Everyone else seems to do it in the vacuum line as long as it is along all four cylindars. Where is that on my Gen II? What could it hurt? Of course, I do not want to ruin the engine. But at the same time, the damn Cat converter, even after market is $1600 in parts. The car is only worth $4K!

 

JC91006, That just simply seems too good to be true! I hope you are both right. First I am going to drive it for a few weeks (actually, I do not need an emissions test until August) and see if that simply does the trick. My first guess is that I knocked some gunk down there. I like the idea for now of just simply throwing a bottle of seafoam in there for a few weeks on every fill up and see what happens. But JC91006, if you are right, then I am in business. I am pretty handy. Are there any special tools or tricks involved in installing the converter? I am a certified welder, so if that is the only issue, then no problem. I will take a look tonight, but it would be nice if it is bolt-in-ready. It just does not make any sense though. One of the threads I read here on PC was about Eastern aftermarket converters. After calling them, finding a dealer, then an installer here in Atlanta, it was only going to save a couple hundred bucks over OEM. It is incredibly hard to believe I can buy one on Amazon that will pop right in place and work correctly for $100??? But for that price, I am willing to give it a shot no matter what. Biggest problem I have had lately is getting a damn Prius up on a ramp! I need a low profile jack just to get under the thing!

 

OK, I looked into the converter recommended on amazon. Found others too. I have stopped sweating at the cost. If any of these work, then I will be pleased that I spent under $300. But now I have a question. I could answer this myself once I get under the car but it is 11PM in Atlanta right now and a very rare cold night. Does the Prius have an electronic port for monitoring the cat? I would imagine so. And does this converter? Is it necessary? I saw one complaint from someone who was upset that the cat did not have a port and had to send it back. They did not own a Prius though. On another note. I am slowly learning about cats. It seems the higher capacity (Liters), the better the flow. How important would this be in a car like a Prius? Is it so computerized that it might actually notice the better flow and think there is something wrong? Could it actually help my performance (mpg and/or performance) if I found one that is higher capacity than the original? The 99205HM is 1.5L. I saw some over 3.5L. Not sure of compatibility yet though. But they came up after doing a search on 2006 Prius.

 

Hmmm. Good to know. not that big of a deal. Since you did it I guess it works. It must be a small chunk of metal to not overheat? Then again, I guess it is on a cat after all. And I suppose I could cut out as much sheet metal as I need to get away from the sensor. Was there an obvious place to put it? In the same place the old one was? For a $100, I am willing to do this once a year! Any ideas on the flow I mentioned? I need to do some research.

 

I appreciate that. But I do intend to take the whole thing off to repair it. There will be no way to weld all the way around the pipe if it is still on the car. My plan is to Tig weld it. I hope it is all stainless. Not galvanized. If so, it will have to be Mig welded. Yuk.

 

OK. Well, with any luck my cat will be cleaned out soon, or at least enough after using a little seafoam for a few weeks. I agree wjtracy. I am wondering what is in this thing. I just can't believe there is platinum in a $100 converter. But I am not too worried about that. I am not exactly sure how a cat converter works, but as long as it works, I guess I don't really care. Some more research for a different time. Right now I am giving my car a good ol' Italian tune up on the highway trying to heat the thing up with acidic fuel cleaner in there. That has not been an easy task with a car that rarely gets over 2000 rpm!

 

I looked at the Magnaflow that I can get at my Oreilly's. About $20 more than Amazon, but it is nice to know I can get it down the street. Same one, (99205HM). It is ceramic (in an outer stainless shell). That is all the database says about it. Nothing about metals. Once again, I have no idea what that means good or bad.