test pipe

[DSMeclipse4G63]

Ok Im just got a high flow cat that is completly hollow. Ive heard stories of people putting these on thier car and the check engine light comes on with a lean code. Has this happened to anyone and if sop what can I change to prevent it...mods are in profile.Thanks
Andrew

 

[1fast97gsx]

if it's completely hollow its not a high flow cat ... it's a test pipe then. you can rewire the O2 sensor with a resistor so there's no check engine light.

 

[1fast97gsx]

the code would be rich anyways... not lean

 

[DSMeclipse4G63]

without a cat it wouldnt allow for proper egr so it would run lean because not enough "unburned" fuel would be let back into the cylinders. Either way I have a fpr and a 190 pump is coming so either way Ill have it covered.
Andrew

 

[NOSNUSE]

With a test pipe the exhaust gases flow passed your rear O2 sensor to fast for it to make a correct reading, henceforth why your CEL comes on, there are O2 sims that replace your rear O2 sensor and fool the ECU in to thinking that the sensor is reading a perfect A/F ratio all the time. Hope this helps you out.

 

[nine5raptor]

Actually it is because the rear needs to always be richer than the front (the cat converter itself uses up 02) hence the voltage will need to be higher at the 2nd 02.

When the ecu compares the 2 readings and sees they are the same, it throws the cel.

 

[gsxtacy]

Nine5Raptor you hitting all the good ones before I can.

Your right again.

The front 02 sensor in the housing corresponds with the rear through the ECU, when the ECU sees two measurements which are out of its metering range it gets confused and tells you to check your engine.

Ignore it, or fix it with the fix mentioned above.

GSXTACY

 

[awdsm drft]

This is only a problem on obdII cars right?

 

[nine5raptor]

yeah, you only have 1 02 sensor

 

[slowblacktalon]

I actually just helped a buddy of mine with this last night. I wired in a 15 dollar resistor inline in his second downstream O2 sensor because he removed his cat. No check engine light now and the car runs great.

 

[DSMeclipse4G63]

how much and where can I get one of those o2 "eliminators"? Anyways the downstream is supposed to stay the same across the board while the upstream is what goes up and down(hence the a/f gauge). Thanks for the good points all I need to do is find a fix so I can put it on. Thanks
Andrew

 

[herostar]

For what it's worth I took off my cat, and have a full 3" from the o2 sensor back with the oxygen sensor in... it hasn't thrown the CEL in the last 3 months (or since I've put it in for that matter...)

 

[DSMeclipse4G63]

I can only hope for the same
Andrew

 

[nine5raptor]

Originally posted by DSMeclipse4G63
how much and where can I get one of those o2 "eliminators"?

these are 02 simulators. an 02 eliminator generally refers to a downpipe that extends up and replaces the 02 housing.

mine: http://www.importparts.com/shop/product_info.php?products_id=2770

this one looks better: http://www.zzperformance.com/zzp/products/prod_o2_simulator.htm

 

[DSMeclipse4G63]

Thanks nine5raptor I will look into one of those if the cel comes on.
Andrew

 

[pickens]

I run no cat, and the ecu will throw a code once a month of so. Before I would just unplug my battery to reset the ecu, then I would be good for another month or so. Now, I just hit the clear codes button my pocketlogger

 

[talonawd94tsi]

does your car lose performance when the cel is on?

 

[nine5raptor]

Not with that cel.


It is just nice to not have that one on in case another pops up (if it was already lit, you wouldn't know about the other one).