Now i know i can just run an obd1 ecu and eliminate the cel. but i don't want to run an obd1 ecu just yet. is there a combination of parts I can run on my 98 integra ls that will help me erase the current cel? I'm thinking of ordering the yonaka catback exhaust cause right now im on a budget and the current exhaust sytem is extremly loud. also the cat has been deleted not sure if the secodary o2 sensor has been removed but can i run a bolt on test pipe with a o2 bung? thanks for any help and clarification.

 

You're gonna get a CEL with OBD2 and no cat. Buy a high flow cat, they aren't that expensive.

Or if you really want to make the code go away without buying a cat, there's plenty of ways to do it that have been beaten to death on forums already and can easily be found with a Google search.

 

Personally, as far as I know, the OBD2 systems typically ran 2 O2 sensors! Now if you install an obd1 computer, you'll lose the sensor for the second o2 sensor, so it shouldn't throw a code because it doesn't exist. As far as aftermarket exhaust, most any "test pipe" cat should bolt right on. OBD0 systems had a 1 wire O2 on the manifold, as well as a oil temp sensor. OBD1 systems have a 4 wire heated O2 sensor, placed on the down tube just before the cat. OBD2 systems have vtec as well as the option to plug in a code reader, where OBD1 does not. What is your CEL code?

 

right I understand how the obd2 ecus and obd1 work. I just wanted to replace the entire system cause they guy basically eliminated the cat with a 2-piece bolt on header and the rest is welded straight pipe. I'm not looking for extreme performance gains etc just want it cleaner and quieter. so the header is staying on for now and hopefully it wasn't welded to the straight pipe. so i can then connect a new cat then the catback exhaust system is this correct?

 

Well, first of all, you need to be sure that you can run that engine on obd1. If it has vtec, you won't be able to (sorry im not familiar with 3rd/4th gen integras as much as id like to be) Second, if you run with no o2 at all, your computer is just going to compensate, and your gas mileage can suffer. Any muffler shop can put a hole in your pipe, weld on an adaptor (18mm if your curious) and allow you to use your current system with probably less headache and money than buying another ECU. I got a PAIR of o2 sensors on ebay for 50$. I also went to the muffler shop, bought their o2 adaptor and used my dremmel to cut the hole for it (drill bits dont stand a prayer) a grinder will also work, but go slow! Other than that, any new parts you buy should be direct bolt on, such as cat and catback and should have no problems bolting right up to the aftermarket exhaust. HOWEVER if its an automatic, there will be an extra piece for the o2, with 2 donut gaskets, and 2 sets of spring loaded bolts. Rather than using cheap "flexpipe" like we do in america. If its an auto, the engine moves A LOT, and if you have solid exhaust, youll either break header bolts, or just keep blowing out donut gaskets.

 

Well i can run an obd1 ecu with a jumper harness but im trying to aboid that. And I'm not worry to much on spending money to replace the exhaust my main concern is if I'll be ordering the right combination of parts etc. Im between getting a high flow cat or just a straight thru test pipe both will have the bung for the 2nd o2 sensor i just want to make sure that as long as tge 2nd o2 sensor is there the ecu will read its presence and not throw a cel

 

Yeah, all you really need to do for the dual o2 sensor system is have a cat and a place for both sensors. You could do it without a cat, but it will likely throw a different code. A cheap after market cat or "test pipe" will only run clean for a short period. An oem cat (typically not bolt on, you'd have to weld flanges on) will give you more longevity. Your possibly cheaper option would be to order a tuned ecu (100-160$ on ebay) and request the o2 sensor be disabled so u don't get a code.

 

Yea maybe a high flow cat with both sensors will solve my cel issue then the smalled catback will auiet everything down

 

Personally I've ran many different set ups. I purchased an OBX "test pipe" cat, and a stainless steel oversized kit 6,7 years ago. It was cheap, 160$ I think. The muffler blew apart after the first year or two. I also have the 2 piece stainless steel header/down pipe. It was only 70$ but I had to heat wrap it, great skill to learn! I put a Thrush turbo muffler on it and loved the mean raw sound at wide open throttle. Then I did a super 40 series Flowmaster 13 inch muffler. Cost 80$. Keep in mind this whole time I was still using the stainless pipes, just cut them off the cheap muffler. The Thrush muffler I had just clamped on, with adaptors. I was on a tight budget. The Flowmaster I had welded to the stainless. That is just WAY too loud but perfect for track days. Now I'm still running the same setup, only this time purchased an OEM muffler. Bolt on. Cost 90$. It's surprisingly damn near perfect now. Very quiet at idle, low hum at mid throttle, and a nice, not loud "classic Honda" tone when opening her up on the interstate. I had a Pacesetter cat back (265$!) on my girlfriend's Nissan, and coveted the sound every day. Now my Honda sounds good and I'm happy. Stainless is MUCH lighter but also thinner so you hear the engine more than with a cast header. However after all that money, 100-160$ for a tuned ecu, plus a cat is still cheaper!

 

Or just get a cat, install a bung for the o2 sensor upstream, and bolt on an oem muffler.