OEM Catalytic Converters Questions

mlara1129

mlara1129

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Searched a bit but couldn't find exactly what I was looking for.

I picked up a pair cats from a wrecked 03 V8 for pretty much the value of scrap, so I didn't think twice. Worst case scenario I scrap them and get my money back.

Anyway, I'm currently running Thunderbolt hi-flow cats and they don't seem to be running optimally. I'm getting terrible gas mileage. They set of a P0420 code twice and a P0430 (original o2 sensors) once. I cleared them and they haven't been back in almost 2k miles, but I came across these OEM cats and I'm considering switching them out.

Here are my questions:
1) Is there anyway to tell visually or test if they are "good"?
2) Anyway to clean them up to improve my chances of them working properly? (I've seen laquer thinner in the gas tank and even washing with laundry detergent on youtube)
-I'm obviously not looking for them to last a lifetime, but another 15-20K would be nice.

The donor vehicle had 86K miles. I know at 86K my LS was running well and I looked at the engine of the donor LS when it was still on and it seemed pretty sanitary. The coil cover bolts seemed to be unmolested, so I guess that could be good or bad. The guy I picked them up from owns the shop where the car is and knew the owner of the LS. Apparently he babied it and was running properly until it was totaled. One thing that concerned me was that the cats were sitting out in the car without the engine for a while so they did take some rain water and snow...

Sorry to keep bugging you guys with my problems lol but any input would be appreciated.

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If those CATs were bad you would see it when you look down the tube the bolts to the exhaust manifold. They look good to me. I will be doing this soon as well. My Thunderbolts are giving me the same probs
 
Yes that was the drivers side on my LSE. I dont know if I have ever heard of washing your CATS...gotta love Scotty Kilmer...lol

I have to take some of the blame here mlara...We had a lengthy PM together about the Thunderbolt CATs and I steered you wrong on them. At the time of our conversation I had never had any troubles or CELs with mine. They were a good price compared to the OEM but these Thunderbolt CATS prove once again that OEM is the best option on these cars (most of the time anyway). Another member had them too and he was having issues but I thought it was the location of his O2 sensors. Sorry about that bro.

I have had 3 CELs with mine. None for the last 1000 miles since I put my factory O2 sensors back in. I have noticed a huge drop in gas mileage but I thought it was the fact that I always drive in 4th now, because I moved closer to work. I have a 5 minute, 35mph drive to work. I figured not driving the highway at all may bring the mpg down a bit. Now it makes more sense to me that it is probly the CATs helping to cause a drop.

When I installed the Thunderbolts I had a bad CAT. So I didnt have any real reference point of the power the car should have. I noticed a gain in power after the switch but with the CATs I also did 2.5" pipe all the way from the CATs back with an x-pipe, resonators and Magnaflows. So naturally it would be more powerful. I believe now that when I put the OEM CATs back in I will notice an increase from where it is now. We will see soon.
 
No worries man, I knew there was a risk going in. For what they cost, I guess they did their work lol I got a good 8-10K out of them.

You have good OEM cats?

And I can't really say I noticed a difference in performance when I switched out my original cats. Although I did beat a few cars I didn't think my LS was capable of beating lol. Wish I could have dyno-ed it. I did love the difference it made in the sound of my exhaust.
 
I dont yet. I am looking for an exhaust system used to cut them off of. I remember seeing complete systems for sale all over when I was switching to the Thunderbolts. One local for $100, complete Cats to the tips...coulda shoulda woulda
 
Ok so question... how are those Eastern's working. Have to replace the drivers side here since I finally had the chance to checkdown the 0420 problem. O2 sensor was bad but the Cat was gone as well. Thunderbolts are out, What about Walkers?
 
IMCO PRO Universal converter is what I used
Got Rid of the P0430
 
Yeah, trying not to torture my muffler shop working on sizing and fitting my cat so Im going with a direct fit setup and right now Easterns and Walkers are pretty evenily priced on the internetz. Just looking for some reviews because you hear good and bad stories all over this site and half the time people don't know what they are talking about... the ones that do get overlooked.
 
I've heard that cataclean works to clean your cats and o2s
Not sure if its true but at 20 bucks its worth a shot
 
My cats are about shot... Guy who had it before me drove it for close to 6 months with CEL before he stopped driving it and sold it to me. Haven't had the ability to take it off the car with little space in my garage for such things. Ill try the CataClene and see if it helps but odds are im still pulling them off. Which is why I asked who has the better affordable cat.
 
I'm getting an Eastern put on tomorrow on the LH side to get rid of my P430 code. $230 is a lot better than the $1000 Ford wants for an OEM. Shop charging me $95 for the install. Dealership wanted $300 for the install. NOT.
 
Ok, thanks.

I'm trying to get the best flow out of one cat for two banks. :shifty:
 
Hey Hite... Hows that Eastern running for you still. Its about time to get one sent in the mail and I've got my shop to put it on... just trying to see if its causing any problems before I jump on it.
 
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