Udr headers/check engine light.

@Brianawd You hooked the 02 sims into the rear 02's, not the AF sensors in the headers, correct? Ive been running the Doug Thorley long tube headers from URD for almost 4 years now with 02 sims and luckily have not had a CEL come on

 

Yes the 0/2 sim is installed in the rear 0/2's

 

Perhaps the sim is just going out of range once in a while, causing the code? If the O2 SIM is borderline on the output, then it should be addressed in the product. Here's excellent info on what may be the issue: http://repairpal.com/OBD-II-Code-P0420-Toyota

 

Well pulled the URD o/2 sim and installed
2 vibrant 0/2 sims. Guess what no more check engine light.

 

Well that is good to hear. Had to just be a faulty unit. Mine has worked well for years. Either way I'm sure you're glad it's corrected.

 

Does vibrant actually make a sim? Part number?

 

It isn't an electrical sim. Just a tube which extends the spark plug futher from the exhaust stream.

 

That's what I thought. You think there are any drawbacks for extending the rear o2 sensors?

 

None. Unless it doesn't work. Cheap enough to try. Worked for Brianawd, and many other people on many other cars.

 

Good eye. Doh. O2 sensor.

 

I just finished my exhaust. URD equal length headers, URD offroad y-pipe and marklll 3" catback. I misread the torque specs for the headers. Headers are 16lbd and flanges are 47lbs? What sort of sounds would one hear that would suggest an exhaust leak? I understand the soot and the common lifter tic (like) sounds but on acceleration I'm getting some rattling, similar to a heat shield and a weird indescribable propeller like sound mixed with a pretty nice aggressive low note. I know.....propeller? But the closest thing I can compare it to would be like a small plane with popeller lol. I only get these sounds on acceleration but in the boost 3000+ rpm @ 1/2-wot and it sounds damn good. Only code I get is the p0300. Still haven't figured this out yet but I drive a spirited 45+ miles daily and it seams to be minor. Unless I'm really experiencing a multiple misfire and that is what I'm hearing now that I'm ABLE to hear it through the larger unrestricted system.
But I've had the 300 code since I got the truck a year ago with factory exhaust.
I also cleaned the maf sensore and throttle body recently and while doing that I discovered I have a 76mm tb from a 2010 5.7 tundra and that the ucon probably doesn't know that since I didn't know the last time I talked to Scott and Gadget @ URD. My next step is replacing the header manifold gaskets and attempting proper torque specs before recording some street runs for Scott and sending them with the throttle body info.
Should I get the thick crush style or the layered steal tyep gaskets? I'd email Gadget but he's a busy dude, it's the weekend and I'd rather work on it than wait for a response.

 

Had that Y-pipe and got that noise - an exhaust leak at medium acceleration. Changed all the gaskets and still had it. Put the original Y back on and it's gone. Think I like the tone of the Spec-U exhaust better with the stock Y anyway.

 

I wouldn't have done it but the old cats were blowing apart. Some are adding a resonator between the muffler and y-pipe.

 

sub

 

An equal length y pipe and two mufflers in the catback will eliminate that noise

 

Second this. Mines still pretty loud and a slight rasp when cold

 

Anybody make a pre-fabbed equal length y-pipe, or is that a do it yourself proposition?

 

I've only seen one and it's for 2wd only. Don't think it's made anymore either.

 

Most reputable custom exhaust shops can easily replicate the APR equal length y pipe. It’s a great design that APR came up with first