Precat removal - How I did it...

Anonymous · December 2, 2005, 09:29

Thats not a bad idea, i think everyone on here who has had a precat faiure, or two as the case may be. to write into watchdog and see what happens.

Anonymous · December 2, 2005, 12:32

im tempted to do it about the corrosion on my alloy wheels too

Anonymous · December 31, 2005, 15:35

DONE!

The instructions here were great. No major problems throughout the whole process.

The most difficult thing was getting some of the bolts/nuts off. Those things are really stuck on there. I stripped the head off of one of the top bolts on the upper heat shield. I'm not going to worry about fixing that one right now. The hardest ones to get off were the 3 nuts that connect the precats to the main cat pipe. Had to go to Lowes and buy a 30" pipe to aid me there.

A couple of things that I found, the bottom bolts on the upper heat shield and the two "hidden" bolts on the lower heat shied were both more easily accessible from the underneath. Also, there's a bracket that connects the lower heat shield to the block (actually 2 brackets). The 12mm bolt I removed from the block. I couldn't get the 14mm bolt out of the block so I removed the other one that connects the heat shield to the bracket. It was much longer and finer threads, but it came out easily.

Once I had everything back together and cranked it up I noticed a lot of smoke coming from the manifold area. Since it kept smoking when I stopped the engine, I'm assuming it is the penetrating oil burning off. I drove it around some last night and it finally stopped smoking. I'm going to take it out again this morning to make sure everything is good.

So thanks for all the help. Now I can stop worrying about the precats.

Michael

Anonymous · December 31, 2005, 15:46

Congratulations on ensuring you have many years of worry-free MR2 motoring left! s:D

s:D

Oh, and welcome to the club Michael: That's not a bad first post to make there. s8)

s8)

Anonymous · January 5, 2006, 03:27

Yep, smoke must have been the penetrating oil. Feel good knowing that the precats are out and the sound is definitely more throaty.

Anonymous · January 5, 2006, 23:53

Quote from: "aaronjb"Expect them to be... tricky s;) s;)

They should be fine (90% of the time) as long as you use a good 6-sided hex socket and plenty of dismantly lube when undoing them, though - they don't rust anywhere near as much as the heatshield ones generally.

Hello again, its been a while since I contacted the forum and once again my limited knowledge of forum etiquette may mean I am going about thing the wrong way, but I do have another very important issue. A while back I decatted my MR2 after the collapse of one of the precats. I had the situation where the engine management warning light came on, and I was advised to disconnect the battery for 20 mins, however after around 40 miles or approx 3hrs of driving the light keeps coming back on. I have returned the car to the Dealer who informs me that the 02 sensor and all of the precat and exhaust needs replacing. This is a major expence and if anyone could advise me how to correct the engine management warning light.
Regards, Gary

kanujunkie · January 6, 2006, 08:24

Gary, when you removed the rest of the precats after the collapse of one, did you clear out the remenants of the precat material that had fallen down on the cat?

As for them saying you need to replace the pre-cats, well sorry to say it but thats b****x. The precats were only put in so that the car could pass the stringant laws on emissions in california. Do not allow them to replace the pre-cats. If the main cat has not been cleaned properly then the chances are you may have damaged the engine. What sort of oil consumption do you have? if none then you may be lucky and it will at worse cost you a new main cat

Good Luck

Anonymous · January 6, 2006, 20:13

Quote from: "kanujunkie"Gary, when you removed the rest of the precats after the collapse of one, did you clear out the remenants of the precat material that had fallen down on the cat?

As for them saying you need to replace the pre-cats, well sorry to say it but thats b****x. The precats were only put in so that the car could pass the stringant laws on emissions in california. Do not allow them to replace the pre-cats. If the main cat has not been cleaned properly then the chances are you may have damaged the engine. What sort of oil consumption do you have? if none then you may be lucky and it will at worse cost you a new main cat

Good Luck

Thanks for the reply, it seems Toyota have turned their back on me. The situation is my engine management light still comes back on and I am currently monitoring my oil consumption, I still dont know how to get rid of the warning light issue, can anyone help?.
The dealer told me my petrol consumption could increase as the engine management system would try to compensate for the imbalance the pre-cats have caused by not being in there. Once again, how can I clear the warning light issue, how have you folks who have decatted like me stopped the warning light from coming back on.

aaronjb · January 6, 2006, 20:33

Quote from: "garystorey"Thanks for the reply, it seems Toyota have turned their back on me. The situation is my engine management light still comes back on and I am currently monitoring my oil consumption, I still dont know how to get rid of the warning light issue, can anyone help?.

Disconnect the battery for 15 minutes. However you need to know what the error code is, really. It could be as simple as a dead O2 sensor - which means you'll clear it, but it'll come back on.

QuoteThe dealer told me my petrol consumption could increase as the engine management system would try to compensate for the imbalance the pre-cats have caused by not being in there. Once again, how can I clear the warning light issue, how have you folks who have decatted like me stopped the warning light from coming back on.

They are talking out of their backsides - sorry, but there's no other way of putting it.

To make this absolutely clear - removing the pre cats will NOT cause the engine management light to come on in ANY circumstances unless there is a legitimate problem with the O2 sensors themselves, wiring, or some other fault with your engine.

Removing the pre cats will NOT affect your fuel consumption in a negative way, in fact, the ECU won't even know they are missing UNLESS your MAIN cat is also knackered. That's because the pre cats are ONLY working for the first minute or so of engine start up, and are ONLY there for Euro III and US emissions standards which we (in the UK) do not go by - hence you'll also pass an MOT.

Right, anyway, back to the subject in hand.

Find out what error code you are actually getting (you'll have to either pay Toyota or see if there's someone local with a code reader you can borrow) and then let us know what that is - my money is that you have a knackered O2 sensor and Toyota are either a) being inept or b) trying to screw you out of a lot of money.

You also need to make sure the main CAT is cleared of debris, in case it's that which is dead.

Regardless, you DO NOT need new pre cats. At all. Ever. Under any circumstances (there, can't make it any clearer than that s;)

s;) )

</Sermon, gets off soap box>

Bongo · January 6, 2006, 20:36

Maybe they've looked, seen no precats and think they've gone tits up as per other cases?

Anonymous · January 6, 2006, 21:24

Quote from: "Bongo"Maybe they've looked, seen no precats and think they've gone tits up as per other cases?

Thanks for the promp reply guys, I recently had the check carried out at a cost of around £95 by the dealer. This is when they told me I needed to replace my 02 sensors, precats and exhaust (£1.3 to £1.5k). If they are wrong about the need to replace the latter items, do you think they may be wrong about the 02 sensors. If I just replace the 02 sensors do you think may will solve the problem. Are they normaly items which are kept on the dealers shelves and have you any idea of the cost.

Anonymous · January 13, 2006, 17:15

Quote from: "aaronjb"
Quote from: "garystorey"Thanks for the reply, it seems Toyota have turned their back on me. The situation is my engine management light still comes back on and I am currently monitoring my oil consumption, I still dont know how to get rid of the warning light issue, can anyone help?.

Disconnect the battery for 15 minutes. However you need to know what the error code is, really. It could be as simple as a dead O2 sensor - which means you'll clear it, but it'll come back on.

QuoteThe dealer told me my petrol consumption could increase as the engine management system would try to compensate for the imbalance the pre-cats have caused by not being in there. Once again, how can I clear the warning light issue, how have you folks who have decatted like me stopped the warning light from coming back on.

They are talking out of their backsides - sorry, but there's no other way of putting it.

To make this absolutely clear - removing the pre cats will NOT cause the engine management light to come on in ANY circumstances unless there is a legitimate problem with the O2 sensors themselves, wiring, or some other fault with your engine.

Removing the pre cats will NOT affect your fuel consumption in a negative way, in fact, the ECU won't even know they are missing UNLESS your MAIN cat is also knackered. That's because the pre cats are ONLY working for the first minute or so of engine start up, and are ONLY there for Euro III and US emissions standards which we (in the UK) do not go by - hence you'll also pass an MOT.

Right, anyway, back to the subject in hand.

Find out what error code you are actually getting (you'll have to either pay Toyota or see if there's someone local with a code reader you can borrow) and then let us know what that is - my money is that you have a knackered O2 sensor and Toyota are either a) being inept or b) trying to screw you out of a lot of money.

You also need to make sure the main CAT is cleared of debris, in case it's that which is dead.

Regardless, you DO NOT need new pre cats. At all. Ever. Under any circumstances (there, can't make it any clearer than that s;) s;) )

</Sermon, gets off soap box>

Hello aronjb, its been some time in coming, but finaly I have the info I wanted. Firstly the dealer informs me that whilst Toyota will contribute an amount, I would still have around £1.4k to pay to correct the cat issue thier way. Your last post advised me to get the error code, it is P0420.
What do you think my next move should be.

kanujunkie · January 13, 2006, 18:04

P0420 Catalyst System Efficiency Below Threshold (Bank 1)

aaronjb · January 13, 2006, 18:35

Quote from: "kanujunkie"P0420 Catalyst System Efficiency Below Threshold (Bank 1)

Aye - so, two options here really..

Either 1) The post-main-CAT O2 sensor isn't working properly, or
2) The main CAT is dead..

1) is only really easy to check if you can borrow someone elses sensor - but you'd likely be getting an O2 sensor failed error if that was the case anyway..

2) Makes me worry that other damage might be going on - but your best bet for a resolution would be to get a secondhand CAT off someone like Adam ("Jap GT300" on here - shoot him a PM and see if he has any)..

Anonymous · January 14, 2006, 14:38

Quote from: "garystorey"
Quote from: "aaronjb"
Quote from: "garystorey"Thanks for the reply, it seems Toyota have turned their back on me. The situation is my engine management light still comes back on and I am currently monitoring my oil consumption, I still dont know how to get rid of the warning light issue, can anyone help?.

Disconnect the battery for 15 minutes. However you need to know what the error code is, really. It could be as simple as a dead O2 sensor - which means you'll clear it, but it'll come back on.

QuoteThe dealer told me my petrol consumption could increase as the engine management system would try to compensate for the imbalance the pre-cats have caused by not being in there. Once again, how can I clear the warning light issue, how have you folks who have decatted like me stopped the warning light from coming back on.

They are talking out of their backsides - sorry, but there's no other way of putting it.

To make this absolutely clear - removing the pre cats will NOT cause the engine management light to come on in ANY circumstances unless there is a legitimate problem with the O2 sensors themselves, wiring, or some other fault with your engine.

Removing the pre cats will NOT affect your fuel consumption in a negative way, in fact, the ECU won't even know they are missing UNLESS your MAIN cat is also knackered. That's because the pre cats are ONLY working for the first minute or so of engine start up, and are ONLY there for Euro III and US emissions standards which we (in the UK) do not go by - hence you'll also pass an MOT.

Right, anyway, back to the subject in hand.

Find out what error code you are actually getting (you'll have to either pay Toyota or see if there's someone local with a code reader you can borrow) and then let us know what that is - my money is that you have a knackered O2 sensor and Toyota are either a) being inept or b) trying to screw you out of a lot of money.

You also need to make sure the main CAT is cleared of debris, in case it's that which is dead.

Regardless, you DO NOT need new pre cats. At all. Ever. Under any circumstances (there, can't make it any clearer than that s;) s;) )

</Sermon, gets off soap box>

Hello aronjb, its been some time in coming, but finaly I have the info I wanted. Firstly the dealer informs me that whilst Toyota will contribute an amount, I would still have around £1.4k to pay to correct the cat issue thier way. Your last post advised me to get the error code, it is P0420.
What do you think my next move should be.

Once again thanks for your interest. I would like to try to resolve my problem using the most cost effective methods first(cheapest). I read on the forum that other owners had used an 02 sensor supplied by GENDAN AUTOMOTIVE PRODUCTS. It seems other than the fact I need to solder the sensor wires myself, there is no obvious difference to the sensor supplied by Toyota, and the cost is approx £35 each as opposed to £140 each.
Do you think this is the best way forward?
I will be contact Jap GT300 to enquire about a secondhand cat.

Anonymous · January 16, 2006, 11:36

After recently buying a 2 reading all of this is quite worrying! I myself haven't a clue about the mechanics of a car but think I want to get the pre-cats removed. I live in Dudley, W-Mids anyone know where I can take mine to get them removed?? This is not a job I'm not even willing to attempt myself!!

Anonymous · January 19, 2006, 15:14

Quote from: "jones380"Does anyone know where I can take mine to get them removed?

A regular shop will not do something like this, so you will have to find a friend of a friend who likes to work on cars.

I had my pre-cats removed from my 2005 MR2 at 10,000 miles as a part of installing a Hass II turbo, and sold them to a man with a 2001 who appears to have experianced pre-cat failure.

He rather suddenly lost all power (best guess was a chunk of pre-cat suddenly clogging his main cat). His engine super-heated and cooked a lot of the stuff around the exhaust. Being out of warrentee he had it taken to a local shop who gave hive a long list of heat damaged parts, but hope that the actual engine would survive.

He bought the entire exhaust removed from my car, from header to chrome tipped tailpipe. I never heard how well the repairs went.

My advice: don't just gut the pre-cats, remove them entirely and replace with a turbo.

aaronjb · January 19, 2006, 18:41

Quote from: "shiftless"
Quote from: "jones380"Does anyone know where I can take mine to get them removed?

A regular shop will not do something like this, so you will have to find a friend of a friend who likes to work on cars.

Actually, some people over here have managed to get either their local Toyota (ok, one person managed that) or a back street garage place to do it for a reasonable sum s;)

s;)

(It's not illegal over here to do.. well.. pretty much anything to your car - no smog or CARB laws over here s;)

s;) )

Anonymous · February 11, 2006, 14:43

Ok............. After reading in several places - the issues that some owners have had - with their pre-cats, going on to cause engine damage, and ultimately engine failure, as I love my MR2 - and have only had it for 5 months or so - hardly any driving in the summer yet with the roof down, I want to keep it. I love this car, and dont want any of the horror stories I have read to happen to me.

I would be very interested in speaking to someone pretty local to myself, who would be able to either complete the removal of the pre-cats for me - or alternatively, let me know if they have had this work completed at a garage etc.

Im an IT guy at heart, PC's not a problem, when it comes to car - air in tyres, water top ups, and checking oil levels, is about as far as my knowledge goes.

So - any one in the Gloucester area that could help me out ?

Willing to pay for the work to be done, dont expect a free-be :-) :-) :-)

Anonymous · February 20, 2006, 22:59

s:cry: :cry: s:cry: s:cry: :cry: s:cry: s:cry: :cry: s:cry: s:cry: :cry: s:cry: s:cry: :cry: s:cry: s:cry: :cry: s:cry:

No one wants to rip me guts out s:-( :-( s:-(

Anonymous · February 22, 2006, 17:51

Just to add that I'd be willing to travel and pay for mine to be done (East Anglia) if anyone has any ideas - eg. another pre-cat gutting meet or whatever.

Roo

kanujunkie · February 22, 2006, 19:06

Quote from: "Roo"Just to add that I'd be willing to travel and pay for mine to be done (East Anglia) if anyone has any ideas - eg. another pre-cat gutting meet or whatever.

Roo

Fraid Mark wont be doing anymore pre-cat gutting meets as he's run out of swear words to use s:(

s:( , if someone else would like to host(airtools, large breaker bar and ramps req as a min) then perhaps another pre-cat meet will be done

Anonymous · February 23, 2006, 17:32

That's fair enough - there are so many swear words you can use! s:lol: :lol: s:lol: Plus it's others peoples' time and stuff, wouldn't expect them just to do it for me for free.

I'm going to try a local garage who I get on with and see if they can sort it. If not, have to reconsider what to do. Really would like to get rid of them though. Far too many horror stories on here for my liking! s:? :? s:?

Cheers

Roo

Peter Wright · February 23, 2006, 17:41

Quote from: "Roo"I'm going to try a local garage who I get on with and see if they can sort it. If not, have to reconsider what to do. Really would like to get rid of them though. Far too many horror stories on here for my liking! s:? :? s:?

Roo
If you have no joy, pop in and see me when your passing my way. I have access to a garage and equipment. Once the manifold is off it only takes 15 min to gut them.
Pete

Anonymous · February 24, 2006, 17:23

Pete - Thanks very much for your offer. I've been to Mr T to get the 'manifold gaskets' as mentioned earlier in this thread. They have a car in at the mo with precat and engine failure s:(

s:( Nearly got them to gut my precats for me, but wouldn't do so as it's not worth the risk if 'something goes wrong' (!)

Try the local garage over the weekend when I go back home, and see if I get on... Fingers crossed s:)

s:)

Cheers

Roo