New Exhaust with New Check Engine Light - Honda Prelude Forum

That 01 BB6 · 08-08-2011, 08:36 PM

So I had my hytech replica header, magnaflow high flow cat, two resonators, and vibrant muffler installed (all 2.5'') and now my car keeps popping a check engine light. It is my front o2 sensor. I bought a new replacement (http://www.oxygensensor123.com/item....DENSO&weight=1) and had it installed. A week later the check engine light came back on

The code was for the front o2 sensor again.

WHAT the hell should I do?

TypeT · 08-09-2011, 02:24 AM

dont buy crappy 5 dollars sensor next time

Kronn 98SH · 08-09-2011, 07:55 AM

Denso sensors are just fine.

That 01 BB6 · 08-09-2011, 08:30 AM

Quote:

Originally Posted by TypeT

dont buy crappy 5 dollars sensor next time

Did you even click the link?

I don't know what could be the problem...

usmcmarc · 08-09-2011, 11:32 AM

Maybe you need one of those offset adapters that back the O2 Senor out a bit. Sorry I cant remember the exact name of them...

indylude18 · 08-09-2011, 11:54 AM

^They are called non-foulers. Those can be used on the secondary sensor, not the primary.

As Kronn posted, the Denso sensors are fine. Are you sure you are getting a CEL for the primary sensor and not the secondary?

TypeT · 08-09-2011, 01:46 PM

Quote:

Originally Posted by Kronn 98SH

Denso sensors are just fine.

yeah, looks like it worked just fine

MisledYouth bb6 · 08-09-2011, 03:01 PM

Does it say upstream O2 sensor or downstream O2 sensor. Upstream is before cat. Downstream is after cat. Hope that helps also post the code it threw.

Kronn 98SH · 08-09-2011, 03:30 PM

Quote:

Originally Posted by TypeT

yeah, looks like it worked just fine

Don't be an idiot. If the OP is telling the truth, something is causing the sensor to fail. That would be a symptom, not the cause.

That 01 BB6 · 08-09-2011, 03:45 PM

It is my primary o2. I run 93 octane if that matters. I feel like with the header and high flow cat, my o2 sensor isnt having time to do its job? i have no idea..

usmcmarc · 08-09-2011, 04:04 PM

I have heard of new sensors just being bad out of the box as well as wires in the connector shorting out from all the tugging and pulling going on when removing the sensor. Have you checked that the connector for the sensor is in good shape? Just a thought.

TypeT · 08-09-2011, 04:14 PM

Quote:

Originally Posted by That 01 BB6

It is my primary o2. I run 93 octane if that matters. I feel like with the header and high flow cat, my o2 sensor isnt having time to do its job? i have no idea..

well that kind of exhaust upgrade will effect exhaust gasses flowing a bit, but havent heard anything before this that it would destroy your sensors...when I modded my car (much more than just exhaust) the air/fuel ration just goed straight to hell, but it didnt effect on o2 sensor. it would be good idea to tune your engine though

minilogoguy18 · 08-09-2011, 05:11 PM

What kind of scanner are you using? Car is more than likely running rich and just throwing a code because, sensor may still be good. Get a multimeter, test the resistance of the sensor and check the wiring on the engine harness leading to the sensor.

Buying parts when you don't know what's wrong is just a waste of money.

That 01 BB6 · 08-09-2011, 06:23 PM

I'll just have pep***s fix it, they installed the new o2 sensor so it's on them. I will have them check the wiring, it's the only thing it could be.

minilogoguy18 · 08-09-2011, 07:20 PM

Well that's your main problem right there, letting a parts store or tire shop work under the hood of your car.

If you're gonna modify a car you should be able to work on it yourself, especially something as incredibly easy as a O2 sensor install.

That 01 BB6 · 08-09-2011, 09:11 PM

I mean I do most of the work myself, just thought there was more to the o2 sensor install I guess.

indylude18 · 08-09-2011, 09:59 PM

The O2 sensor just screws into place, and the wires have a plastic clip on the end, you just plug it in. You'll have to jack up the car to get to it...that is probably to most time consuming part of the whole process.

I would suggest switching your O2 sensors to see if you still get the same code. If you do, then the sensor is not the problem. If you don't....well then just leave them switched. The secondary sensory is far less important than the primary.

TypeT · 08-10-2011, 04:07 AM

how about this: by changing the whole exhaust has made fuel rations too thin and now it throws o2 sensor code when it cannot balance it

minilogoguy18 · 08-10-2011, 05:56 AM

Quote:

Originally Posted by minilogoguy18

Get a multimeter, test the resistance of the sensor and check the wiring on the engine harness leading to the sensor.

Buying parts when you don't know what's wrong is just a waste of money.

^indylude18

TypeT is more than likely right.

indylude18 · 08-10-2011, 09:04 AM

There are plenty of people (like me) with 2.5" header back exhausts that don't have a CEL for the primary O2 sensor.

Your suggestion of how to check the sensor works too, but the way I suggested is easier. That would be why I mentioned it.