S14 3-way cat removal.

[ORL240]

I had my 3-way cat removed on my 95 240sx w/ 96 ka24de (pretty sure it's obd2) about 2 years ago because I heard it was extremely restrictive and I didn't have money for header. This is the cat that sits immediately after the stock exhaust mani. I had a friend that owns a muffler shop remove it and weld a 2" elbow that connects to the pseudo cat under the car.

My questions is does this have any negative effect on performance or fuel economy. My seat of the pants dyno told me that car is a little quicker thru the rpms w/o cat and fuel economy has pretty much stayed the same. But I have the check engine light on, w/ code 105 & 41 coming from ecu.

I know 41 is for air intake temp sensor, mine is broke, but this doesn't really affect ne thing right?

Search'd but all cat posts were bout s13's or passing emissions.Posted in 240-tech but no help.
Modified by ORL240 at 4:48 PM 12/22/2005

[Skidmark]

I don't think 72 is a valid code, or at least it isn't in the FSM. Are you sure you're reading it right?

[ORL240]

Thanks skidmark.Actually I think it's 36 or 38. Have to pull ecu again tonite and will post again with correct error code.

[Skidmark]

Yeah recheck and let us know what's up.

[ORL240]

re diagnosed ecu, error codes 105 & 41.

Bad air intake temp sensor is not a big deal right?

105 is for egrc solenoid I think. What does this mean for performance and fuel econ.?

Car has been running fine.

[Skidmark]

Hey, you're gonna want to smack me, but I misinformed you before. My dumb butt was reading the S13 FSM. 72 is a valid code, and guess what it goes to... your 3 way catylist. LOL sry, I had to go d/l and S14 FSM to make sure I wasn't lying to you, hehe. Anyways, IMO you don't need ANY of that emissions BS and it's probably better off being broken, LOL. As far as the temp sensor, I'm almost positive that's not a critical function, either, but if it makes you feel better I'm sure you could snag one from the junkyard for next to nothing. Heck it might not even be that expensive brand new, dunno I never bought one. I personally just learned to live with the C/E light on all the time when I removed my emissions crapola. Anyhow you've got the problem(s) figured out, take 'em or leave 'em

[zukitek]

Im quite sure that the bulb can be made not to illuminate,I think since the IAT sensor is used for air/fuel calculations it would be a good idea to make repairs.

[ddgsxr504]

I don't think 72 is a valid code, or at least it isn't in the FSM. Are you sure you're reading it right?

I don't think he mentioned code 72, he said 105 and 41. Either way 105 is the EGRC soleniod and 41 is the IAT. You can get a new IAT for pretty cheap at the dealer and it is something I would replace. Your EGR code problem is up to you. You don't really need it (EGR Crap) unless you plan on passing smog which is a problem I don't have to deal with anymore. If you read my signature you can see what I have and I haven't had any problems with it at all. You run a little rich and your gas milage will suffer city driving 300-350mpg but I still get 400-425mpg highway so it's up to you. As for the check engine light I just took the damn bulb out.

[Ligouri Rd]

Ok, you have a '95 S-14 with a '96 motor right? Did you use the '95 ecu (OBD1) or '96 ecu (OBD2)? The problem is with the obd1 ecu they dyno test your motor to see if it passes emissions which you probably won't without the cat. You may want to get another factory "down pipe" with the cat to use if you have to go through emissions (ebay or ask local SR swap shops if they have it left over).

I was lucky that with a '96 (obd2) if you get all the codes to stop showing up they pass you imediately. I did have to get an oxygen sensor similator to fix the rear o2 sensor code. I also have two "down pipes" available, so I could gut one and leave the other alone.

As for drivability, I saw no increase in fuel economy. I did notice a loss of torque and gained a few tens of a second of my quarter mile (i.e. I was slower).

[ddgsxr504]

It depends on his car, not all 95's are OBD1, mine is OBD2.

[Ligouri Rd]

Good point...forgot about that. So how do you tell if the car is obd1 or 2, I thought they both had ports?

[ddgsxr504]

I know one way to check it is.... If you have a second O2 sensor, 2 wires running into the sensor is OBD1, 4 wires is OBD2. I am sure there are easier and quicker ways to find out but I don't really care enough to find out or bother to know.

[Ligouri Rd]

If you have a second O2 sensor, 2 wires running into the sensor is OBD1, 4 wires is OBD2.

-More exceptions to the rule, my '96 has a secondary cat but it has three wires going to it. Its also some oddball size much smaller than the primary o2 sensor. I also have a '97 downpipe and o2 sensor, it has four wires and is the same size as the primary sensor.