: Another Headers Question



AlmostAV
03-22-08, 12:18 AM
what is running untuned kooks long tubes with no cats going to do to my rear 02 sensors readings, and the car as far as it running smoothly is concerned? Will the rear o2 readings send a emergency signal to the pcm and cause the low power mode.


thanks so much for your help

SkullV
03-22-08, 01:00 AM
No low power mode....but I have gotten 2 check engine lights this week for low catalytic converter efficiency.

JonCR96Z
03-22-08, 01:03 AM
I don't have a tune for the headers, but I had the rear 02s turned off when I had previously got tuned. It runs a little rich and blacks the tips up pretty quick. So, you have that to look forward to along with the engine light.

randycsvt
03-23-08, 12:13 AM
why not just get mil eliminators for the rear O2's. They keep the rear O2's from throwing check engine lights. That is what I did with my last car before I tuned it and had the rear O2's shut off.

AlmostAV
03-23-08, 01:31 AM
Couple things.

1. Check engine light came on. Funny thing is, in didnt come on till the 2nd time I drove it. I turned it on prolly 20 times with no check engine light? Hope nothings messed up

2. I couldnt fit my torque wrench to torque the spark plugs or the header bolts to spec. So I tightened till I felt it was solid. Whats the torque spec on the bolts from the motor to gasket to the header?

3. Im hearing a wierd whirring/engine noise coming from the engine when the throttle is blipped. Does this mean I prolly have a leak where the header meets the motor?

4. I hear my exhaust tinging, is this the new welds getting adjusted. Or is something prolly just rubbing....like the bar across the x pipe area?

5. The guy who welded the fabbed connection pipes took all 4 o2 sensors out, saying without cats they are useless, and dont do anything. Is this correct?

Thanks alot.

AlmostAV
03-23-08, 01:37 AM
The muffler guy took all 4 o2 sensors out??? Is this bad?

heavymetals
03-23-08, 01:48 AM
Yes.

heavymetals
03-23-08, 01:53 AM
Why don't you yank the PCM and shove a carburetor on it?

Seriously, you need the two front 02's for the computer and those are before the cats (your muffler guy is real sharp on that one!).

The last two are checking cat efficiency so they are not that important and can be turned off via the PCM.

It takes a while for the PCM to be convinced something is out of range before it throws a code or light.

benelliwang
03-23-08, 01:54 AM
Yeap, the 2 front O2's are needed for the LTFT and STFT. Put them back on asap. The rear ones are for smog purpose only, it will cause a check engine light but will not effect performance. You can do a mechanical O2 sim or buy an electornic O2 sim and keep the error from happening. When you decide to turn the car later on, just have the tuner turn off the rear O2 DTC.

benelliwang
03-23-08, 02:06 AM
Couple things.

1. Check engine light came on. Funny thing is, in didnt come on till the 2nd time I drove it. I turned it on prolly 20 times with no check engine light? Hope nothings messed up

2. I couldnt fit my torque wrench to torque the spark plugs or the header bolts to spec. So I tightened till I felt it was solid. Whats the torque spec on the bolts from the motor to gasket to the header?

3. Im hearing a wierd whirring/engine noise coming from the engine when the throttle is blipped. Does this mean I prolly have a leak where the header meets the motor?

4. I hear my exhaust tinging, is this the new welds getting adjusted. Or is something prolly just rubbing....like the bar across the x pipe area?

5. The guy who welded the fabbed connection pipes took all 4 o2 sensors out, saying without cats they are useless, and dont do anything. Is this correct?

Thanks alot.

1. On some codes, it takes a few trips to trigger the check engine light. It is because you took off all 4 O2 sensors. You need to put 2 front ones on asap. Then add O2 sims to the back or tune out the error code.

2. Yes, it is fine but make sure you do torque them again after one week. They could get loose after some heat cycle.

3. Header leaks are typically a ticking sound.

4. No idea what tinging means in this case. With the car running? Off? During acceleration? Constant tinging? Like a bell?

5. Your exhaust guy is a retard. Er... I mean your exhaust guy is wrong and he should run for the presidency...

I've replied to your other post with more detail if you care, good luck.

Naf
03-23-08, 10:56 AM
why not just get mil eliminators for the rear O2's. They keep the rear O2's from throwing check engine lights. That is what I did with my last car before I tuned it and had the rear O2's shut off.

The o2 sensor elimitors are crap...Dont spend your money on them...I got a pair from casper, and it kept throwing codes. Especially when i accelerated hard...

jbss71
03-23-08, 01:21 PM
i know i'm new but i've covered this already in the two weeks i've been here. i'm sure i wasn't the first.. this place is a pain to find stuff because of repeat threads that clutter up everything