RT help. I've new exhaust nuts stuck. Any ideas?
- Thread starter 2001LC
- Start date
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This thread is a pretty good reminder why I do all the mechanic work I possibly can myself. It's hard to trust anyone else with even simple R&R work.
you havwe nothing to lose cleaning it, if it works than it works. if not then you were probably going to repalce it anyways so no real lose
To add insult to injury, O2/AF sensors should be replaced in pairs-( double the cost of the techs error now). I would bite the bullet and replace now while you have everything at easy access- and not waste time cleaning- then later having to remove after youve found the cleaning to not work.
2001LC
SILVER Star
- Thread starter
- #25
Me too. Everyone gets very concerned when buying to see a good service history. I find history useful as places to double check.
I do agree.
I pulled the CAT for a few reason. One of which has to do with diagnostics. I had/have new bolts, nuts and gasket in hand. I'm thinking now I may have enough threads on stud remaining and may be able to restore them, reinstall CAT, O2, plug and see if I get a P0430 again. Then come back later and replace the studs or whatever I need.
I've heard that before. Are they any "studies", "data points" or "what have you" on old vs new performance. I've never really look at these as good, weak or bad.
One thing it did learn, is I did not clogs the CAT when I used 44k, Cat-clean, Seafoam fogger.. Engine does not show nor does CAT of indications of running rich, blowing oil or coolant in exhaust and that Midas screwed this up badly. Could they have done a worst job!
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Cross threading nuts keeps them from backing off. It's a safety thing. 
Old thread but I am curios what fixed the code as I am having similar problems with new aftermarket cats.
I now have at least 3 cross threaded and one broken studs. This is additional headache that I really did not want to have.
Will start drilling and extracting broken one tomorrow.
I now have at least 3 cross threaded and one broken studs. This is additional headache that I really did not want to have.
Will start drilling and extracting broken one tomorrow.
2001LC
SILVER Star
- Thread starter
- #32
Bummer! I hate busted and cross thread bolts.
But my cause and cure for CAT DTC (codes) was/is different than you'll find. In that I've a VVT engine. It's cause of CAT DTC, is only found in the VVT engine (2006-07).
Bottom line CAT go bad for number of reason:
A) Most CAT go bad, are due to up stream of exhaust manifold issue. (all I've seen)
1) Engine operation issue. This is only reasons I've every found for CATs going bad, in the 100 series.
B) They're few issue post exhaust manifold gasket at head back. That can cause a CAT to go bad. The FSM and a few here will say exhaust leak. Which I've seen and correct many exhaust leaks. Some very bad pre CAT went on for 10's of thousands of miles. But I've never seen one have or cause a bad CAT. Although they can cause a CAT DTC.
My P0430 & P0420 & S.A.I DTC in a VVT engine:
For me fixing the mess Midas Muffler made installing the BK2 CAT. Which had air leaks at every point it could possible leak. Was only the starting point down stream.
In addition I found Midas Muffler had replace S.A.I. #2 SW BK2. They messed that up as well. In that the SW's air pipe where it bolts to exhaust manifold BK2 leaked. So there was another air leak pre CAT I had to fix.
But correcting all exhaust leaks. Was not all that was needed. There still was "why did CAT go bad in the first place" at only ~150K miles. Additionally I was still getting S.A.I. DTC's and sometimes even S.A.I. #2 SW BK2 which I had fixed the air leak & replace with OEM SW (Midas Muffler used aftermarket).
Furthermore I started getting BK1 CAT DTC P0420. Even P0430 came back at times, with it's aftermarket CATs leaks corrected. Which I do still have that BK2 CAT Midas Muffler installed in, and had too replace BK1 CAT. But that was not the end of my DTC.
I'd also worked my way up stream to engine itself. I eventually correct the cause that started all DTC from the S.A.I & CAT. It's now been a few years without any DTC.
forum.ih8mud.com
But my cause and cure for CAT DTC (codes) was/is different than you'll find. In that I've a VVT engine. It's cause of CAT DTC, is only found in the VVT engine (2006-07).
Bottom line CAT go bad for number of reason:
A) Most CAT go bad, are due to up stream of exhaust manifold issue. (all I've seen)
1) Engine operation issue. This is only reasons I've every found for CATs going bad, in the 100 series.
B) They're few issue post exhaust manifold gasket at head back. That can cause a CAT to go bad. The FSM and a few here will say exhaust leak. Which I've seen and correct many exhaust leaks. Some very bad pre CAT went on for 10's of thousands of miles. But I've never seen one have or cause a bad CAT. Although they can cause a CAT DTC.
- Exhaust leak.
- Impact to CAT, busting it internally.
- Flood water washing in muck.
- Clog in exhaust.
My P0430 & P0420 & S.A.I DTC in a VVT engine:
For me fixing the mess Midas Muffler made installing the BK2 CAT. Which had air leaks at every point it could possible leak. Was only the starting point down stream.
In addition I found Midas Muffler had replace S.A.I. #2 SW BK2. They messed that up as well. In that the SW's air pipe where it bolts to exhaust manifold BK2 leaked. So there was another air leak pre CAT I had to fix.
But correcting all exhaust leaks. Was not all that was needed. There still was "why did CAT go bad in the first place" at only ~150K miles. Additionally I was still getting S.A.I. DTC's and sometimes even S.A.I. #2 SW BK2 which I had fixed the air leak & replace with OEM SW (Midas Muffler used aftermarket).
Furthermore I started getting BK1 CAT DTC P0420. Even P0430 came back at times, with it's aftermarket CATs leaks corrected. Which I do still have that BK2 CAT Midas Muffler installed in, and had too replace BK1 CAT. But that was not the end of my DTC.
I'd also worked my way up stream to engine itself. I eventually correct the cause that started all DTC from the S.A.I & CAT. It's now been a few years without any DTC.
S.A.I. Filter Modification, in VVT engines. To prevent its failure! Alert Alert!
We've a $2.00 part in the S.A.I. (secondary air injection) system of the VVT engine, that is taking-out ~$7,000.00 $15,000 $25,000 (inflation) in parts. WOW! I've a very easy and cheap WORK AROUND. You are going to love this ;) This thread is dedicated to the 4.7L 2UZ-fe VVT engine, in the...
forum.ih8mud.com
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After spending few days on it, was able to put 3 nuts back on each side.
Lessons learned:
1) Try not to brake the studs. You could cut or grind the nuts but don’t strip or brake the studs.
2) It is easier to deal with the stripped stud than broken stud. Broken stud requires drilling and tapping the threads. Had to buy more tools to work in that tight spot
3). FSM states that those nuts are one time use. I did not know.
I got the codes P0430 P0420 back again. The next steps are new downstream oxygen sensors.
Lessons learned:
1) Try not to brake the studs. You could cut or grind the nuts but don’t strip or brake the studs.
2) It is easier to deal with the stripped stud than broken stud. Broken stud requires drilling and tapping the threads. Had to buy more tools to work in that tight spot
3). FSM states that those nuts are one time use. I did not know.
I got the codes P0430 P0420 back again. The next steps are new downstream oxygen sensors.
