Are you running a st8 pipe or is the main cat still intact?

 

Exhaust leak. Tighten all the exhaust bolts evenly. Did you replace the donut gasket after you gutted the pre-cats?

 

+1 on what Vatik says. Just happened to me and I found loose connections in the exhaust system even though it was torqued to spec on installation. Go figure.


jack

 

@triz - no, the main cat is still there...

@Vatik - it wasn't me who gutted, i bought the car that way, so i donno if gasket was done with it...

@jkohms - i saw your previous post few weeks back! i'm hoping i have same one. is there any specific one i should target for? the bolts around the header?
do you happen to know the the torque spec?

 

Hyojiggy,

There is a torque spec sheet in the Big Green Book. You may wish you replace the donut gasket between the header and main cat pipe. They run about $17 from Toyota or $12 for a generic from the autoparts store.

You can also take the back bumper off, start the car, and feel for air leaks at each flange.

 

I have the same scenario, CEL's on for same code. Has been for the last year, will go off for 700 miles, then on... Today I went to a decent muffler shop (credible and been around forever) and discussed the problem with the owner. He thought as long as the original precats are gone, in my case with the Che header, in the OP's case, decatted, that it is inevitable to have a CEL P0420. All about the variance in temperature or whatever is read between the "upstream" header's two O2 sensors and the "downstream" sensor.
I'm guessing this is too obvious and would have been answered for me earlier when I posted about this code.

 

I'm not saying your guy doesn't know what hes talking about, but I can tell you what i know from personal experience with my own vehicle. I've run it 3 years with precats removed and never have gotten a p0420. Well I did once after I got my new exhaust installed, but it went away after I tightened some some stuff down. Still precatless and still no p0420 to this day.

 

wow, this time it took a while... i don't drive my Mr2 a lot, but it finally kicked back in.

P0420 Generic - Catalyst System Efficiency Below Threshold (Bank 1)

Freeze Frame Data
Fuel Sys 1 - CL
Fuel Sys 2 - CL
Calc Load (%) - 9.41
ECT(*C) - 85
STFT B1(%) - -1.56
LTFT B1(%) - -3.13
STFT B2(%) - -1.56
LTFT B2(%) - -2.34
Eng RPM - 3414
Veh Speed(km/h) - 103
IAT(*C) - 26


what the hell does this mean.

 

wow, this time it took a while... i don't drive my Mr2 a lot, but it finally kicked back in.
P0420 Generic - Catalyst System Efficiency Below Threshold (Bank 1)

What have you checked / replaced thus far?

 

P0420 Generic - Catalyst System Efficiency Below Threshold (Bank 1)

Freeze Frame Data
Fuel Sys 1 - CL................Don't worry About it
Fuel Sys 2 - CL................Don't Worry About It
Calc Load (%) - 9.41........When the 'Cel' came on, You were Almost Throttle Closed
ECT(*C) - 85....................Engine Coolant Temp was 85 Dec C..Normal running Temp
STFT B1(%) - -1.56..........Short Term Fuel Trim was pulling a Little Fuel (-)
LTFT B1(%) - -3.13...........Long Term Fuel Trim has Figured you need -3.13% of Normal Fuel
STFT B2(%) - -1.56..........Short Term for the Other Fuel Bank is -1,56% Pulling a Little Fuel
LTFT B2(%) - -2.34...........Long Term Fuel Trim for the Other Bank has Settles on -2.34% Fueling Correction
Eng RPM - 3414.................RPM when the Cel Came On was 3414
Veh Speed(km/h) - 103......103 KPH when the Cell Came on
IAT(*C) - 26......................you were sucking 25 Dec C Air ..

Throttle was almost Closed and you were travling about 70 MPH when the Cel Came On

The ECU and the O2 Sensors are Playing very Nice with each Other, by looking at your Fuel Trims.. The Long Term Corrections and the Short Term Corrections are VERRY NICE!.. Same Direction and Less then 5 total.. your car is behaving it self very nicely

Your 420 code is likely caused by an Exhaust Leak.. and by looking at the Fuel Trims.. it's not at the Head to Manifold Joint.. as the Long and Short Fuel Trims would not be so Even if the Leak was at the Head, As the O2 Sensors would be 'Sniffing' Free O2 From the Exhaust Leak..


This leaves the Donuts at the Three Amigos or a Crack in the Pipe AFTER the two Main O2 Sensors..

You can Pressurize the exhaust pipe with a Shop Vac Hooked to Blow.. then you can crawl around the COLD exhaust pipe looking for the Leak..

The Previous Owner did you a Favor by Gutting the Pre-Cats. And the Exhaust Shop just helped to perpetuate the inaccurate Information that the Pre-Cats are necessary for the Main cat and the Final O2 Sensor to Work Properly.. They are Not.. The Pre-Cats are just Little Cats that heat up sooner.. ( By a Few Minutes ).. and get the Car 'Cleaner Sooner' than without.. The O2 Sensors ( 3 Of Them ) will not know if the Pre-Cats are Gone.. as the First Two are Before the Pre-Cats, There fore the Pre-Cats will not Affect them.. and the Last O2 Sensor is after the Last Cat.. So it's still after the Only Working Cat.

IF the Spyder had an O2 'Air Injection System' BETWEEN the Pre-Cats and the Main Cat ( Some Cars to for Nox Reduction ), then things would be Different.. But That is not the Case Here.. Pre-Cat Removal will just Save your Engine. Your Car will no Have an 'Exhaust Profile' of a Celica GT.. they use 1ZZ Engines and No Pre-Cats.. So By Gutting the Pre-Cats your engine will now live about as long. and pollute like, a '00 Toyota Celica GT

Cap

 

Cap Weir...
:thumbsup::icon_thumright:


:bow:

ie:happy thanksgiving!

 

.... this is a bad start...

rusted bolts.. already PB'd it for past 3 days... won't budge. no fun...

 

Take the Car to a Muff Shop, and Have them use the Torch to heat the Heads of all 6 Bolts ( 8? ) to a Cherry red hot.. then let them cool.. then hit them with the Pent Oil.. They will come out.. Let it soak for a few more days.. Try not to break them.. No Fun..

Cap

 

It's really not that bad if they break, those just hold the heat shield onto the header. I remember they made a snapping sound like they broke on the one that broke and on the other ones that just came out (that PB blaster was applied to).

 

well, would keeping the engine warm and applying the PB help?

 

If it was warm then it will just vaporize with the heat like spraying a hot pan with water. It would probably help to let it soak then drive the car to heat cycle the bolts causing them to expand and shrink then more PB, they will be difficult to get off though.

I would just say break them then take it to a machine shop if you need to, no point in just taking the whole car there in the first place imo. All the stuff to get the header off the engine are under shield and then the three amigos.

 

One of my header bolts was stuck pretty tight and I ran the risk of stripping it. I called a friend who's very knowledgeable, and he used a hammer and a punch to "shock" the bolt by placing the punch in the center of the bolt head, holding it straight up (parallel to the shaft of the bolt) and whacking it hard with the hammer. What it does is produce a sharp motion that jars it enough to separate the rust that's bonded the threads in place. Worked like a charm. I've since used the same technique to loosen a few other bolts.

 

p

I also use the same technique at times but if you have an impact gun it makes life easy because of the hammer. Porsche owners have no choice but to use the punch method on what they call their cheese bolts.

 

My exhaust leaks were where the header meets the downpipe and also where the downpipe and cat meet. Both can be reached from under the car. Have you tried just tightening what's there already? Engine to header was fine.

jack

 

you just answered my last post.


anyone know what torque it needs to be tighten?

 

well, going back to the original problem or having the 3 amigos tightened,

do i REALLY need to take this shield off?

can't i peak it from under and try tightening it?

or... is this something that you'd say

"you're gonna break a bolt, not worth sweating over and take it to the shop"?

 

i got a quote from random muffler shop near by... they say they can do the job for $225 + parts...

anyone know a good shop near S.F. area who can hook me up?

 

I work below Salinas.. In Soledad.. If you happen to be this way, after work, I'll get the Bolts off for you.. All of my Work Tools are here.. I've got another set at Home.. But that's 1 1/2 Hours South.. Wrong Direction for you..

Won't be back in this area till Monday of next week.. But I've got the Time and tools, If you've got the Energy..

Cap

 

i won't mind the drive~ i love to drive if it's works out, may be i can stop by monterey too!

any who.... i PB'ed it for another 2 days.. and i got this. and i didn't force this or NOTHING! i swear!

POOP!

 

Now I might charge you to fix that..

The rest is Free..

Cap

 

keke!


anywho, i did what another person suggested previously...
just lift up the car and check the 3 amigos from the bottom.

they looked okay for me. they bolts were all very tight, and didn't seem to be loose or anything.

car threw another CEL P0420
P0420 Generic - Catalyst System Efficiency Below Threshold (Bank 1)

Freeze Frame Data
Fuel Sys 1 - CL
Fuel Sys 2 - CL
Calc Load (%) - 31.76
ECT(*C) - 85
STFT B1(%) - 2.34
LTFT B1(%) - 1.56
STFT B2(%) - 3.13
LTFT B2(%) - 1.56
Eng RPM - 3833
Veh Speed(km/h) - 117
IAT(*C) - 15

so, Cap Weir: do you think it's still the donut gasket issue? *shrug. i don't have a clue.

 

The Fuel Trims look Good, so the Likelihood of the Head to Exhaust Header leak in minimal ..

That would indicate the leak might be at the amigos.. Or the Cat is actually dying.. A Temp Test will tell.. As per a Posting by WTS, the outlet temp of the Cat should be hotter than the inlet temp by 100-150 Deg F.. A Hand held IR temp gun will tell.. But as of yet I have not been able to get a Reading on my Cat.. as too much heat shielding to get a Reading..

If the Exhaust to Head gasket is good, then the heat shields do not have to come off.. So.. Pressurize the Exhaust Pipe with a Shop Vac, hooked up to Blow.. Do this on a COLD pipe, and Jack the Car up.. you will be able to feel around and find the Leak.. It has to be the Amigos, or the Flex Pipe Leaking.. as the Joint after the Cat will not toss a 420 code..

Post what you find..

Cap

 

.. It has to be the Amigos, or the Flex Pipe Leaking.. as the Joint after the Cat will not toss a 420 code..

is it possible to replace JUST the Flex Pipe with stock piece?
http://www.ppeengineering-onlinestore.com/category.sc?categoryId=23


unfortunately, i have no shop vac..

i have tons of computer parts laying around, for being an IT guy...:huh:

Dam, i need to go look for someone with a shop vac.... i wish i owned a car shop...

How about trying this! >
keeping the engine cold initially, remove the rear bumper... spray some diluted bubble soap around the 3 amigoes/flex pipe area, and run the motor and see if i see some bubble forming?! or do you think the pipe will get hot fast enough to evaporate the diluted solution?! freaking MacGuyver!

.. i'll just look for someone with shop vac...

 

useful How-To:

http://www.spyderchat.com/forums/showthread.php?t=30036&highlight=rear+bumper+remove



but thanks to my manager, i was able to find a shop vac, and got to do the test..
i donno how to embed a video in here...

http://www.youtube.com/watch?v=ROTPztvERpU

so Cap Weir, looks like we're gonna meet up after all..

any specific type of food you like?:biggthumpup:

 

How many broken heat shield bolts do 'We' have to fix..

Mostly I'm a Pizza and Diet Coke kinda Guy..

Cap

 

just that 1

i can leave the heat shield off until we get that fixed, right?

*btw, i'll pick up parts. don't wanna take your time for my crap

 

VICTORY IS MINE!!

i just had to give it a shot myself.. went to autozone and borrowed a breaker bar.. no stripped bolts or nuts!

got new donut gaskets in and no more leak!

that should fix my p0420 right?

 

If it comes up then you know you have a bad cat.

I had a bad cat and had to have it replaced so its not out of the norm.

 

It's always nicer to do it yourself.. ( Unless it involves the Septic Tank! )..

And have a Back up Plan.. 'Plan B'

So I gotta buy my Own Pizza?..

Cap

 

It's always nicer to do it yourself.. ( Unless it involves the Septic Tank! )..

Cap

For me it's wheel bearings. I will do just about everything else but not wheel bearings.

 

well,

after the work on the new donut gaskets,
i ran the motor...

there was a lot of airflow exiting out of the tail pipe. does that tell me anything?

and this was before the donut fix... the exhaust used to make slight noise like "put. put" not very laud when i let go the gas pedal.. (not all the time), but did... could this be related?

 

You will know once you drive on the highway for about 20-30 minutes at operating temperature.

 

well, i've been driving it since the repair... drove about 100+ miles local and freeway (mostly freeway)..

no CEL so far :icon_thumright:

 

Good to hear.