Blown cats - What are my options

conaero

Forum Owner
Messages
34,594
Just something to add and hope it helps:

If you change your header/cat pipes from Euro to US or US to Euro you need to also change your heat shield and this in turn may require you to change your oil pump to oil tank pipe as well to get the heat shield on.

If you don’t put a heat shield on, the manifold super heats the oil pump to oil tank pipe which in turn thins the oil and throws a Slow Down and low oil pressure warning light.
 

2b1ask1

Special case
Messages
20,223
Do I take it that the second lambda reaches your proposed bung position behind the steering rack without faffing with loom routing then Newton?
I’m curious why you’d opt for us style headers at all really....!? Shorter individual lengths are t optimal. And if they don’t need to incorporate cats, and the cabling needs fettling in line with eu type layout anyway, I’m confused what drives your choice? Ground clearance maybe?

Ok, I can see that was not a clear explanation, I intend to keep the existing US type manifold plate (secondary air) and final flange to meet existing primary pipes. These will be new parts. Also to maintain if practical the heat shields. Beyond that everything would be replaced to give equal length pipes and a better collector.
 

2b1ask1

Special case
Messages
20,223
In addition the idea being that it can be done in stages and OEM (stock) secondaries can become your primary cats with the addition of welding a boss after them on each side for the rear O2 sensors.
 
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342
I'm already planning to remove the secondary cats. This is just a "worst case scenario" outlook so I can know whats the maximum amount I'd have to spend, I'd replace the O2 sensors first and see what happens from there.

Did anyone try the larini headers? What do they do that prevents the CEL from showing up?

Jumping in a bit late to the party.

I have a US car, bought with 55,000 miles and blown primary cats. Sorted it by gutting the primary cats and adding Larini sport cats. Relocated existing O2 sensors just downstream by adding a boss for them. No CEL, all done in short order, outstanding performance and sound.

The more ambitious header project also sounds promising, but the Larini solution was out-of-the-box easy.


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Twinspark

Member
Messages
460
Jumping in a bit late to the party.

I have a US car, bought with 55,000 miles and blown primary cats. Sorted it by gutting the primary cats and adding Larini sport cats. Relocated existing O2 sensors just downstream by adding a boss for them. No CEL, all done in short order, outstanding performance and sound.

The more ambitious header project also sounds promising, but the Larini solution was out-of-the-box easy.


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Thats a good cost effective solution, if you can send me pictures of the bottom of the car that would be great.

Edit: These are the larini sport cats and it seems that it has 2 holes between the cat, is this possibly a plug for the sensors?
4200_detail1.jpg
 
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TimR

Member
Messages
2,656
Its pretty much what I said at the start of the thread TBH
It wouldnt take much to get a set of custom primary pipes made up with sports cats and a bung..Bet they'd be cheaper than Larini...!Itd be loud though...
I have a set of decat primary pipes fitted...that 2nd cat accounts for alot of noise attenuation..ALOT.

Here...watch this and learn....
 
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Messages
342
Thats a good cost effective solution, if you can send me pictures of the bottom of the car that would be great.

Edit: These are the larini sport cats and it seems that it has 2 holes between the cat, is this possibly a plug for the sensors?
4200_detail1.jpg

Should be able to snap a pic this weekend as it’s time for brake pads after a few rather aggressive and protracted play times at the track.


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midlifecrisis

Member
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16,102
I think ceramic coating will keep the engine bay cooler but exhaust hotter. Granturismos do use their fans a lot.
How expensive is expensive?
 

Twinspark

Member
Messages
460
Just a few more things... my car does have the P0132 code but when driving it does not show a CEL and has never shown it before, will a failing primary cat (or more likely to) trigger the CEL?
 

Zep

Moderator
Messages
9,110
P0132 is short circuit in the heater in the lambda sensor, so it looks like that is not working correctly either.
 

Twinspark

Member
Messages
460
P0132 is short circuit in the heater in the lambda sensor, so it looks like that is not working correctly either.
There is definitely one of them that’s wrong, but is there any possibility that I can pinpoint whether its the front or rear sensors?
 

Oneball

Member
Messages
11,075
Just a few more things... my car does have the P0132 code but when driving it does not show a CEL and has never shown it before, will a failing primary cat (or more likely to) trigger the CEL?

Does your CEL illuminate when you turn the ignition on?
 

Oneball

Member
Messages
11,075
No I’ve never had a CEL, there is however some rattling underneath which could be the secondary cats.

Your CEL has been bypassed or the bulb has blown.

It should light up when you turn the ignition on as a self check.

Your P0132 code should light it up too.
 

Twinspark

Member
Messages
460
Your CEL has been bypassed or the bulb has blown.

It should light up when you turn the ignition on as a self check.

Your P0132 code should light it up too.
Ok so I initially did not get what you meant but just now I have just checked the “light check” when turning on the accessories.

And...

The CEL has been bypassed :mad:

Thats another issue to add to the very extensive list.

I have driven the car today, while it does pull it struggles particularly around the 3-5 rev range. The problems found were two faulty coils(1 and 5) along with the cat/lambda sensor issue. Its also quite smelly at the front of car its producing a burning smell.
 
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Messages
342
Thats a good cost effective solution, if you can send me pictures of the bottom of the car that would be great.

Edit: These are the larini sport cats and it seems that it has 2 holes between the cat, is this possibly a plug for the sensors?
4200_detail1.jpg

Here are a few pics (of dubious quality) from under my 04 Coupe with Larini sport cats and the rerouted O2 sensors

ca0cc35b8085b29df0489c8921aede70.jpg

83aa5f82f1c66e0c4252a3759cd10a18.jpg

39d1850edaa71b0e998b24bc99168fb9.jpg



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2b1ask1

Special case
Messages
20,223
The CEL has been bypassed :mad:

Thats another issue to add to the very extensive list.

Ouchie!

That is an MOT failure in itself I'm afraid...

Local MOT guy tried to fail my lads Fiesta for it and I literally had to take the dismantled clocks into him to prove it had never had one fitted even though it had an ODBII port and the clocks have the lens where one could be! He took the time to email DTP to have it recorded as such and swore he'd never seen that combination before.
 

Twinspark

Member
Messages
460
Would like to say I also have a P0103 code which indicates a high voltage for the MAF sensor, since both the MAF and lambda have high voltages could the problem be from an electrical component like the alternator?