Yabo

Okay.. Of course after that whole broken exhaust studs in my head and everything, and welding a leak just before the cat, and replacing every single exhaust gasket and sealing ring and every bolt and nut...... I failed emissions again.

Oh don't forget, I changed O2 sensor during that job,,, too!!!

Here are the numbers......

Reading Limit
HC GPM 3.15 2.25 FAIL
CO GPM 16.72 23.74 PASS
NOX GPM 4.08 3.25 FAIL
CO2GPM 726.99 ----

also said fuel economy 11.54 (not sure what that means.., but just incase it matters thats what it is).

Any help here? The guy said he thinks I need a new cat... I just welded up this cat pipe and spent all this time on it.. hoping its not it.. any ideas? I need to fix this within 30 days... I had to pay the 47 bucks for inspection, and i'm leaving for college in like 3 weeks so it has to be before then.. HELP!!

I also have NOx HC CO2 and CO graphs to post if it would help? Let me know

Any help would be appreciated. Also wondering if a used cat would be a good source or do I have to go new?? I'm in real money trouble right now and I could use an inspection.

NeedPorscheSpeed

I'm sorry to hear of your negative result, Devon. I am just thanking my lucky stars that my state doesn't require inspections. Best of luck in passing that next inspection.

Red1

High NOx is a sign of a lean condition. Check the easy stuff for vacuum leaks. Any vacuum hoses, cracked j-boot, or loose hose band. Just be glad you're not troubleshooting a 951. There's a LOT more crap to throw your emissions off on those.

86 951 Driver

Put some of that guranteed to pass stuff in there and make sure that you drive your car on the highway in 4th gear to get it really nice and warm. If it works great. If it doesn't then your not out really any money just time.

Jakerx

hey at least your car runs, even though not legally

Yabo

yeah except i think i only get one free retest.. i really need to get it right this time...should i get a new cat and the garunteed to pass stuff? What is that stuff exactliy anyway...... something I put in the gas? Is it harmful?

Mike1982

Well, I didn't pass because of my high NOX, well I got a waiver because I spent over $300 in the last 90 days on the exhaust, wastegate. I know a few car guys who say if the NOX is that high it is the cat. But REALLY check for vacuum leaks as well. Cheap too!!! Other then that, I MIGHT think a engine sensor but I am not 100% sure because I just don't care that much about it. My car runs good and never showed a problem going in, so just a little advice. Hope this helps some.

Charlotte944

Devon:

Make a LONG run and check your fuel mileage. 11.54 (I'm assuming Miles Per Gallon) is about half of what you should be seeing. Most NA cars get somewhere in the mid-20's for around town driving, and in the upper 20's to lower 30's for highway driving.

Also, post some pics of your spark plugs.

Finally, check your fuel pressure, and verify that the fuel rail holds pressure when the engine is NOT running.

Yabo

I do know my fuel pressure is good.. just had that checked at a mechanic for another problem a month ago... Will give pictures of spark plugs later today.

I don't believe that i'm getting 11.54mpg... I have been getting great mileage lately I think.. i've been getting at least 350-400 miles per tank...

Waterguy

I assume this was a "rolling road" variable speed dyno test. High hydrocarbons usually indicate rich conditions, while hugh NOx indicate lean conditions. A new oxygen sensor should have cured the rich condition if everything else is working right, but it sounds like you are rich and lean on different parts of the accelerate/cruise/decelerate cycle. Post the graphs; they may help sort out what is going on.

RMills944

Okay, go to the testing station, park in the lot next door, pull an injector wire, then go have it tested. The car will pass with flying colors. Basically, you are now using a 3 cylinder and using the fourth as an air pump leaving VERY little traceable exhaust particles. Seeing as the car will not run too well, you do not want to do this for long, but you can pass emissions like this. I have passed a few cars like this and it has bought me time to get the problems fixed. As I said, this is a temporary solution. It'll run rough(obviously), ut it'll get you through.

Yabo

um... considering i am getting a retest.. they can't fail me for running that rough...or question it at all?

Yabo

Here's the charts...

Bold line is marked as "YOUR VEHICLE"
Lighter thin line is makred as "SPEED"

Any help is appreciated.. thanks.

goingboeing737

Plus, make sure you drive at least an 30/45 minutes at highway speed right before testing.

Older cats need to be plenty hot to work best.

If you are going to use the "guaranteed to pass" stuff, you need a couple of days in advance to run it through the system.

Make sure the O2 sensor that you replaced is wired right and no soldering the wires...

I did replace mine (cat) when i first bought the car. Got a "universal" with lifetime warranty installed at Midas for about 280.00.

Here is my results from a couple of months ago. The top is the "fail" the bottom is the "pass". Difference was another O2 sensor and going back to stock injectors. A TOTAL PITA.....

Yabo

seems like you passed HC first time fine too... so i dont know if it would be that.

One question about the02 sensor. The one i got (bosch universal, about 75 bucks) was a 3 wire. I spliced the wires together with bosch's crappy plug kit... and that was it. One question i do have... on the 02 sensor there is one black wire and 2 white wires. The white wires aren't able to be mixed up are they? Because there was no way to tell when splicing them in which whites to what whites. I imagine porsche would've colored them with a stripe or something if they needed to be distinguished from each other, right?

Also wondering, my exhaust always has somewhat of a strong smell. Not antifreeze, but something else.. It's just a bit more fumey than I would expect. Any chance changing back to regular oil (instead of mobile 1) would help my emissions? I don't know if i'm burning oil.. I do lose oil but i also have a couple leaks.

Thanks for all the help