[LesPaulBluesBreaker]

Hi Everyone........ just run into my first potential problem with my '04 4200GT Coupe CC with only 20,000 miles on it.
I had the check engine light come on. I had it checked out at the Maserati dealer in San Antonio and the fault appears to be that I have an overheating cat on the right hand side. The car seems fine and is drive-able right now, however, It seems quite likely that I will have a problem in the not too distant future. There is no way in hell that I'm going to replace crap with crap (ie stock Maserati parts) so what do you guys recommend? I would like to keep the exhaust similar to stock; maybe just a tad louder as the wife still has to drive it too!

 

[Lorenz-06MT]

First off park it. Theres no way in hell id drive it. You could potentially damage the engine if you keep driving. Theres a recent thread in here that JLOBO put up. He gutted his cats and sent his ECU to get reprogrammed and thats what i plan on doin if i ever have to. From what ive been seeing its the most inexpensive way to fix this issue. This really sucks that at 20,000 miles this fails. Its bull

 

[TravisJ]

I agree - don't drive it until it is fixed. There are lots of informative threads on the subject but don't be afraid to ask if your have specific questions.

 

[JoshH]

I would want to make sure the engine is running properly as well. With a cat over temp problem this early on, I suspect you have very slight misfires causing raw fuel to run through the exhaust and cause the overheating cat.

The usual suspects in that scenario are worn spark plugs, faulty ignition coils and an ailing camshaft timing variator solenoid.

Anything is possible, but it is unusual for a catalyst to completely fail on it's own this early.

 

[reniliu]

That's to bad, but this is not under warranty as part of the emission control system ? Maserati warranty this for a period of 8 years or 80 k miles. This is the problem with Maserati
to many premature failure that cost a ton of money to fix it. Also i would not drive the car under this condition.

 

[Theronh357]

First off park it. Theres no way in hell id drive it. You could potentially damage the engine if you keep driving. Theres a recent thread in here that JLOBO put up. He gutted his cats and sent his ECU to get reprogrammed and thats what i plan on doin if i ever have to. From what ive been seeing its the most inexpensive way to fix this issue. This really sucks that at 20,000 miles this fails. Its bull

Dude, are you serious?
I'm sorry, but if you're suggesting gutting your pre-cats and getting an getting an ECU remap from Evolution as an "inexpensive" alternative, then I suggest that you think again.

 

[MaseratiGSGB]

I think it has been mentioned before, Larini now make headers Maserati 4200 - Larini 'Sports' Exhaust Manifolds (OE 2 Header Cats/2 Cats)

 

[TravisJ]

Dude, are you serious?
I'm sorry, but if you're suggesting gutting your pre-cats and getting an getting an ECU remap from Evolution as an "inexpensive" alternative, then I suggest that you think again.

What is a less expensive solution to correct a failed pre-cat condition?

 

[Lorenz-06MT]

Dude, are you serious?
I'm sorry, but if you're suggesting gutting your pre-cats and getting an getting an ECU remap from Evolution as an "inexpensive" alternative, then I suggest that you think again.

Dude??? Im not sure of the tone of your text but Im not gonna get into anything with you here. But JLOBO, a member here, who i have also talked on the phone in depth about this issue had gutted his cats for a few hundred bucs, then sent out his ECU to EVOMS and had it remapped for 1,600 bucs. I would gladly pay two grand to fix a pre cat issue. If you have a cheaper solution to this please tell us.

 

[TravisJ]

Dude??? Im not sure of the tone of your text but Im not gonna get into anything with you here. But JLOBO, a member here, who i have also talked on the phone in depth about this issue had gutted his cats for a few hundred bucs, then sent out his ECU to EVOMS and had it remapped for 1,600 bucs. I would gladly pay two grand to fix a pre cat issue. If you have a cheaper solution to this please tell us.

I personally feel like the ECU remap is pointless just for the cat issue. I believe this is the most cost effective work around for bad precats...

1) Gut the existing precats (possibly illegal)
2) Replace the main cats with FD aftermarket units (main cats are typically contaminated when precats fail)
3) Extend rear O2 sensors downstream from the main cats (this has some challenges but is MUCH cheaper than an ECU remap)

 

[Lorenz-06MT]

I personally feel like the ECU remap is pointless just for the cat issue. I believe this is the most cost effective work around for bad precats...

1) Gut the existing precats (possibly illegal)
2) Replace the main cats with FD aftermarket units (main cats are typically contaminated when precats fail)
3) Extend rear O2 sensors downstream from the main cats (this has some challenges but is MUCH cheaper than an ECU remap)

Yea but Travis, if you remember, JLOBO not only remaped the ECU so that the 02 sensors wouldnt go off, but he also had something done to give him a much better throttle response similiar to the DBW. so to me he did two things with one shot....And also FD aftermarket cats are not cheap ether. Out of curiosity how much are FD aftermarket cats? Never mind i just looked. Their $850, then you have the labor to install and then you have to move the sensors, and the sensors have to be mounted in the correct spot for the proper reading so they dont throw a code.. Seems like quite a bit of work. ID rather go the other way,,seems much easier to me, especially if your gonna gut the pre cats anyway

 

[LesPaulBluesBreaker]

Thanks for the great info guys............. it's always a pleasure to deal with you all. The knowledge and experience is priceless.

Unfortunately Maserati in SA are really not much help; all they really want to do is unbolt stuff, bolt on factory replacements and then charge an arm and a leg for it. I'm still searching for a good indi here in San Antonio. They couldn't even tell me if it was the primary or secondary that was causing the problem. Although I'm guessing it has to be the primary as isn't that where the sensor is located?

So..... gutting the primaries and re-welding them, replacing the secondary cats with Larini (from FD) and re-locating the O2 sensor to the rear of the new Larini cats seems like the way to go.

A couple of dumb questions though: If I live in TX where emissions are not an issue, do I need the cats anyway? Would the car run without them or does it need the back-pressure? Why does the O2 sensor need to be relocated?

Again, thanks for all the great help and info on this site!

 

[Lorenz-06MT]

If you live where emissions is not and issue you dont need cats, car will run fine, You will still have some back pressure from your mufflers. If you guts cats and install FD cats you will have to relocate the 02 sensors or you will throw a code. On the other side of this, If you gut cats, remap the ECU, you wont need the 02 sensor and at the same time they can give you much better throttle responce, which makes a big difference. I would check and read JLOBOS thread, its interesting. Then look at your options

 

[TravisJ]

Yea but Travis, if you remember, JLOBO not only remaped the ECU so that the 02 sensors wouldnt go off, but he also had something done to give him a much better throttle response similiar to the DBW. so to me he did two things with one shot....

I thought we were talking only about catalytic converter issues. If we are talking about multiple modifications, then that changes the picture.

And also FD aftermarket cats are not cheap ether. Out of curiosity how much are FD aftermarket cats? Never mind i just looked. Their $850, then you have the labor to install and then you have to move the sensors, and the sensors have to be mounted in the correct spot for the proper reading so they dont throw a code.. Seems like quite a bit of work. ID rather go the other way,,seems much easier to me, especially if your gonna gut the pre cats anyway

I think you are missing the point of the FD aftermarket cats. Those are needed to replace contaminated main cats. An ECU remap isn't going to uncontaminate main cats. Moving the O2 sensors has nothing to do with the main cats. It is just a more cost effective method of avoiding a CEL. Much cheaper than an ECU remap.

 

[Lorenz-06MT]

Your rite, we are talking about cat issues. But what im saying is if you have a cat issue, one option is to gut them and have EVOMS do a remap to eliminate the 02 sensors going off, and at the same time have EVOMS enahnce the throttle response, just like JLOBO did. ....On the other hand......As far as FD cats are concerened, their a great product and another way to go, but what im saying is if you install FD cats, you first gut the primary cats, (Cats by the Header), install the FD cats downstream, then you have to move the 02 sensors, correct?. If you do this, then of course no remap is needed,

 

[TravisJ]

Pre-cats are in the headers and main cats are downstream. When pre-cats fail, the catalytic converter material either gets sucked back into the engine or blown downstream contaminating the main cats. The least expensive fix for the cats themselves is to gut the pre-cats (in the headers) and then either replace or remove the [now-contaminated] main cats downstream. Welding in aftermarket main cats, like the FD units, is generally least expensive as they are cheaper than factory replacements and also cheaper than the Larini options.

When pre-cats are gutted, there will be a CEL unless someone relocates O2 sensors (presuming they have main cats), uses spacers on the downstream sensors (reportedly hit or miss), or does an ECU reflash. Of those options, relocating the downstream sensors is least expensive. Someone could relocate the sensors and install a FD DBWEM for less than an ECU reflash.

 

[Lorenz-06MT]

I could never figure out why we call the downstream cats the main cats....seems to me that the header cats with the 02 sensors would be the main cats.......the downstream cats secondarys.

 

[TravisJ]

I could never figure out why we call the downstream cats the main cats....seems to me that the header cats with the 02 sensors would be the main cats.......the downstream cats secondarys.

It could be partly due to size (the main cats are much bigger) but it is probably because ROW cars only have the main cats. Pre-cats are unique to NA cars. Since all 4200s in the world have the cats downstream from the headers, it is natural to consider them the "main" cats.

 

[Lorenz-06MT]

I think Jlobo paid 1600 for his reflash and im not sure what all he had done, but when i called EVOMS, i told them i wanted more throttle response and that i wanted to stop the 02 cell from coming on if i gutted my cats and he quoted me a price of $1250. I thought that was a pretty good price to get one issue resolved and a mod done at the same time. If i have an issue with my cats,,,(knock on wood) ill be going in this direction to kill to birds with one stone. As stated above, relocating the sensors could be a hit and miss and i wouldnt want to have to keep messing around with that. Id rather go for the sure thing Jlobo said scince he got his done his throttle response is razor sharp. Soon as he hits the pedal hes off and running.

 

[TravisJ]

I think Jlobo paid 1600 for his reflash and im not sure what all he had done, but when i called EVOMS, i told them i wanted more throttle response and that i wanted to stop the 02 cell from coming on if i gutted my cats and he quoted me a price of $1250. I thought that was a pretty good price to get one issue resolved and a mod done at the same time. If i have an issue with my cats,,,(knock on wood) ill be going in this direction to kill to birds with one stone. As stated above, relocating the sensors could be a hit and miss and i wouldnt want to have to keep messing around with that. Id rather go for the sure thing Jlobo said scince he got his done his throttle response is razor sharp. Soon as he hits the pedal hes off and running.

I'm not saying the EVOMS deal is bad. Just a very expensive fix for an O2 sensor issue alone. For multiple mods it may be great. If you are looking for throttle improvement now, I think the DWBEM is the best bet. Do you really want to wait for a pre-cat failure to get that mod done?