Derekcat

iTrader: (8)

Hey, I searched, and might have the solution, but I'm curious about why this happened

I have a 90' vert that has just been rebuilt, and I'm trying to get it to pass DEQ..

At about 700mi with no gasket between the exhaust manifold and the rest of the exhaust, all stock engine bay, some unknown age aftermarket single cat, I got 400 Hydrocarbons [220 limit], and was OK on CO and NOX..

[in between these two tests I put a gasket between the manifold and the rest of the exhaust.. and one of the nuts disappeared. Also I've driven a couple hundred more miles so I was at 930mi for the second test]

Thinking of how I've passed both of my S4 NA cars, I connected the airpump output to the split-air pipe, put two bottles of Isoheet in 1/8th of a tank and... got 1200 Hydrocarbons and failed on CO [I can't remember if NOX passed this one or not.. But it doesn't matter]

This second test the check engine light was on [it comes on after I've driven on the freeway a few minutes], but the check engine light isn't a new thing.. It's been coming on since we got the car running. [codes are 15 and 17]

From Rotorwiki.com: "* 15 - Oxygen Sensor - Feedback cancelled
* 17 - Feedback System (poss O2 sensor) - Feedback cancelled"

I went back after checking that the tube was still connected to the split air pipe and the air pump, and shut off the car right before the test [to make sure the check engine light wasn't on], but the results were more or less the same..

I'm going to try changing the O2 sensor tonight [my friend already told me to do this before I checked the codes], but that doesn't explain at all why the HCs TRIPLED, and the CO jumps into the failing range..

Just curious [Silly S5... Why can't you be easy..]

Derekcat

iTrader: (8)

Well, I couldn't get the stupid O2 sensor off, so I dropped it at the exhaust shop this morning..
For the est. the guys noticed that the split air pipe to cat connection is broken and that my cat has pieces bouncing around inside, and that the cat has been overheated.. >_>

Any suggestions for after they get the work done [I'm having them install a header with a new O2 sensor, and replace the broken cat].. and I've only got until.. Tomorrow to get it past DEQ :P

Derekcat

iTrader: (8)

Incase someone finds this thread someday...

The end was this: I brought it to the exhaust shop to get the header installed [I can't cut/weld] and they noticed the cat had been over heated, and the connection between it and the split air pipe was bad, and the insides of the cat were bouncing around :P

Sadly whatever company made my header didn't think about convertibles when they built it, so the rear subframe piece didn't fit on.. But that's a different issue