what was Toyotas fix for precats issue 03-05???

[z27ls3]

does anyone have an idea what toyota did to address the MR2 spyder precat issue, I keep seeing that after 02-03 (whatever) the issue is fixed.
sooooo what was "the fix" ?
I need the fix.
00 spyder, mint cond and 50K miles.
no intention of letting it go and want to make this possibility go away.
also looking for a bolt on swap, what would be best ?
maybe a salvage later model manifold? or???
some of the aftermarket options seem cheaply made.

[MR2Jedi]

I had an '01, lightly moddified and never had an issue.
Not sure what you're talking about.

[RPAltman]

On model year 2000-2002 Spyders, there was a known problem with piston rings 'sticking' on the 1ZZ-FE engine; Toyota issued a Technical Service Bulletin to its dealers in the UK (but not the US). Toyota changed the design of the piston rings on the 'facelift' version of the Spyder introduced in late 2002 as a 2003 model.

It is the source of much "chicken or egg" debate whether it’s a case of:

(1) Stuck piston rings fail, which causes oil to drip onto the pre-cats, which leads to pre-cat deterioration from oil exposure, which results in pieces of pre-cat sucked back into the engine, scratching and scoring the cylinder walls, which leads to more oil passing by the piston rings and being burnt off without you even realizing it, or
(2) The pre-cats break down due to age and blow into the main cat causing excessive back pressure, which leads to leads to greater oil blow-by, which leads to more oil passing by the piston rings and being burnt off without you even realizing it.

Regardless.. it's a very bad thing either way. Common symptoms of pre-cat failure are (1) extreme oil loss and (2) lack of power all the way through the rev range. By the time the oil pressure warning light comes up, it's too late to do anything.. there’s almost zero oil left in the engine.

There are isolated cases reported on the forums of 2003+ models (which had improved piston rings) suffering pre-cat failure.. so the piston ring design did not eliminate the problem. Ultimately, there is no hard evidence available to conclude on which is the cause and and which is the effect.. and Toyota isn't interested helping prove they sold a car with a defective design given the low sales volume of the vehicle and cost to repair.

All we know for certain is that, while you can’t remove piston rings from the engine, you can remove the pre-cats from the exhaust header manifold. If you have no pre-cats, there's nothing to get sucked back into the engine.

Rich

[z27ls3]

thanks for the response, I'll be blowing the pre-cats out as soon as possible.
only have 51 or 52K miles on and its been on mobil1 as far back as 20k as I can prove.
I suspect I'll be ok on the rings, thanks again for the info.

[MR2Jedi]

Wow. I guess I was lucky. I got rid of my '01 Spyder with around 65K miles and never a single issue. Niether excessive oil consumption, or cat failure. I did have a freer flowing Team Moon Dual exhaust, but I can't see that that would have prevented any of the problems brought up here.
Interesting.

[RPAltman]

Originally Posted by MR2Jedi

Wow. I guess I was lucky. I got rid of my '01 Spyder with around 65K miles and never a single issue. Niether excessive oil consumption, or cat failure.

In addition to the "chicken or egg" debate regarding the source of the problem, the magnitude of the problem is very uncertain altogether. I know there are Spyder owners on the forum and Spyder owners I've run into on the street who've driven 150k miles (or more) without removing the pre-cats or suffering the ill effects of pre-cat failure.. but I've also seen plenty of Spyders on the forum and on the street that have experienced a sudden and mysterious loss of oil combined with the destruction of the pre-cats which led to a sudden and unexpected catastrophic failure of the engine.

[MR2Jedi]

Interesting.
I did hear about the excessive oil usage and the SMT's,but never anything about the precat.
I did get rid of mine at around 66K miles and even though it was lightly mofiied, I thought it was just too under powered for it's looks.
It was to drive though.
Thanks for the FYI.