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Discussion Starter · #1 ·
Hi,

I live overseas (Central America) where there is no federal regulation such as the one in the states. I am going to the mechanic tomorrow to have the catalytic removed at his recommendation (Cat is not available at local parts stores). HE suspects the my cat is clogged as 97 Rodeo 3.2 V6 is experiencing hesitation upon acceleration and very sluggish and hesitant on hills.

My question is, what will happen to the O2 sensor or sensors? How many are on a 97 3.2 V6? IS he going to bypass them?

Reason I ask is because he also mentioned that my O2 sensor is bad. He connected an Actron OBII scanner and advised that the sensor is bad.

I was going to replace the O2 sensor but since we are going to remove the cat, I don't know what will work best.

Also, my exhaust has a STRONG gasoline smell like gas is not being burned and my fuel economy is really bad.

Will O2 sensors be needed if we remove the cat? I am hoping that I run leaner rather then rich as I suspect due to bad O2.

All in all, what I want to accomplish are:

1. Fix hesitation upon acceleration,
2. Improve gas mileage,
3. Stop strong gas smell from tailpipe (possible rich mix due to bad O2)

I want to go the economic route before going crazy spending money in other parts. If hesitation and gasoline smell do not stop, I then will replace plugs with NGK's and possibly the fuel filter.
 

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You do still need the O2 sensors. Even if removing the cats, the O2 sensors provide critical data to the ECM so that it can properly tune the engine. Also, without the cats, the exhaust will forever smell gassy.
 
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Discussion Starter · #3 ·
CatFuzz said:
You do still need the O2 sensors. Even if removing the cats, the O2 sensors provide critical data to the ECM so that it can properly tune the engine. Also, without the cats, the exhaust will forever smell gassy.
Thanks CatFuzz for you $0.02. Would you happen to know how many O2 sensors I need for this 97 Rodeo V6 3.2? I tried finding the info by searching the forum but I have been unsuccessful. Thanks
 

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System,

The following seems to suggest 4 sensors for a '97 3.2L: viewtopic.php?t=40024

Also, go to Google and input something like "planetisuzoo 1997 rodeo o2 sensor" . Google does a great job of searching the Planet!

HTH,

GB
 
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You are going to need an O2 simulator for the fourth sensor or a modified code in order to prevent a check engine light.
 

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By removing the cats, you will have a check engine light. There's no way around that but something tells me that's not going to matter where you are. There are normally four O2 sensors. The O2 sensors after the cats do not have anything to do with how the engine runs, so they won't really matter. They serve as a check on how the cats are performing and nothing more. With no cats there at all, the ECM will see that and throw a code. This is assuming, though, that your Rodeo is even built the same as North American Rodeo's are built. It may not have the same emissions equipment depending on where it was originally sold new.
 

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Discussion Starter · #7 ·
CatFuzz said:
By removing the cats, you will have a check engine light. There's no way around that but something tells me that's not going to matter where you are. The O2 sensors after the cats do not have anything to do with how the engine runs, so they won't really matter. This is assuming, though, that your Rodeo is even built the same as North American Rodeo's are built. It may not have the same emissions equipment depending on where it was originally sold new.
Wow! Whats with the "4" O2's?? Overkill. I priced the O2 down here and it goes for $80. I'm looking at $320!! This particular Rodeo was brought from the states by land via Texas ---> Mexico--->Guatemala---> then El Salvador. Original owner was from Texas.

What would you guys do if you were me? Should I just bypass all cats and O2's and run naked? I'm just looking to get rid of hesitation and improve FE.
 

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It's actually not overkill. There are two cats, one for each side of the engine and there are two O2 sensors per cat. One in front and one behind. Like I said, the O2 sensors after the cat are not going to matter. It's the one's on the engine side of the cats that determine how the engine runs.
 

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If the vehicle is currently running okay other than the cat, I suggest getting a replacement cat. There are plenty of online places to order one. That is the best solution. If you do anything that will cause it to set a code, as long as the light is on, the ECM will be functioning in "limp mode", and your performance and gas consumption will suffer. Dennis
 

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Agreed unless you spend the money on a simulator for the after cat sensors or eliminate them from the code you will be running with a check engine light and the ECM will be in "limp" mode and performance will suffer anyway. Figure out what is cheaper a simulator kit or new universal high flow cats and go from there.
 

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Whatever Central American country the OP is in, it may be difficult or very expensive to import parts from outside the country. The "limp mode" that has been referred to isn't entirely accurate. If the front O2 sensors are functioning properly, the ECM can make accurate calculations (as long as other various sensors are also functioning properly). Just because the CEL is on, doesn't necessarily mean the ECM is in default mode, which is not really a limp mode, it's simply a default set of values that may not be quite as efficient.
 

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Can the mechanic provide you with the codes from the ODB II? I'm reading somewhat between the lines but it sounds like

Check Engine Light On
Poor Performance
Smells like unburned fuel

This could all be from one or both of the upstream sensors being bad. As others say if you don't mind the CEL being on all the time you can for sure pull the cat and should run decently but if the upstream O2 sensor is bad and causing the mix to be too rich just removing the cat will not change anything - it will still be rich, will still run bad and will smell even worse.

You can get O2 sims but those typically are for the downstream sensors whose only purpose is to look for a difference in what it sees and what the upstream O2 sees - all it does is checks to see if it looks like there is a catalytic converter in place. Putting in O2 sims doesn't fix the improper mixture nor does it keep the CEL from illuminating.

Is philosophical argument I guess but if the CEL light is on all the time how will you ever know if the only problem is the one you know about or if it is indicating some other new problem?
 

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If the OP is in Venezuela, where gas is like 18 cents a gallon, I would not be concerned about fuel consumption.... :p
 

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Discussion Starter · #14 ·
Thanks to ALL who replied and provided there $0.02. I want to let you know that one of my problems has been FIXED!!! WHOOPEE!!! After removing the cat and driving without the car, THERE IS NO MORE HESITATITON. Turned out to be a CLOGGED CAT.

I had previously posted this Hesitation issue here: viewtopic.php?f=1&t=68366 It now feels like I have 50% more Horsepower, no more hesitiation!!! I was getting ready to sell this truck due to hesitation issues where others had mentioned that it may be due to bad spark plugs, bad clutch or even a bad G Sensor.

After taking down the Cat and analyzing it, it was Definitively CLOGGED, as I moved it or turned it it rattled inside like it had pebbles. I was not able to see through it in direct sunlight.

Next up: Figuring out what to do with the (4) O2 sensors down there. There are 4: 1 before and after the cat, and 2 on the manifold.

IMPORTANT: The mechanic and I were only able to find and see 1 Catalytic. Cat Fuzz, you mentioned there were 2? Did I miss one? Can you point to a diagram of the V6 3.2? Thanks!!
 

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If it's a V-6 and came from North America there definitely should be two cats. One on each side of the engine.
 

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Discussion Starter · #18 ·
CatFuzz said:
If it's a V-6 and came from North America there definitely should be two cats. One on each side of the engine.
Well, I have a Manual Transmission w/ 3.2 V6. According to IsuzuParts.com diagram for the exhaust seen here, the manual tranny only brings one. Seems the Auto brings 2. Whats the deal with that? Can you take a look and confirm? Thanks!

The cat we took out today is the exact one seen in first diagram labeled #2. Exact location as well.

See attachements or go to link below:

https://www.partswebsite.com/isuzuparts ... type=parts
 

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That's odd but I think you are correct. I never would have guessed that it would have only one cat for a V-6.
 
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Actually, OEM CATs are very expensive (especially the type of CATs that were made in the 90's), I do not understand why they had two of them in the first place. You only need one on single exhaust system.

OP, did you end up using O2 simulator?

Rear O2 sensors DO NOT send you into "limp" mode. And for that matter, even the front O2 sensors do not make anything drastic. ECU operates the engine in "open loop", which isn't a big deal, this happens anytime you start your car (for around 5min) and anytime you go into WOT (most ECUs ignore O2 feedback at WOT).

Now, loose an airflow sensor or TPS, then you will see a REAL LIMP MODE! :)
 
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