Aleks951

Hi All,
So I just took my car to have the SMOG pre-test on the rolling dyno and it didn't pass. It looks like if failed NO at both 15mph and 25mph. I've read some of the other posts regarding SMOG tests so I'd like to know if anyone has any decent recommendations. Here is the info:

15 MPH (2516 rpms)
HC 46 (measured) [116 max]
CO .48 (measured)[ .74 max]
NO 1628 (measured) [791 max]

25 MPH (2371 rpms)
HC 34 (measured) [91 max]
CO .31 (measured) [.62 max]
NO 1346 (measured) [730 max]

The car came from Florida and has APE chips, and Fabspeed cat-back exhaust with about 122K miles on it.

I don't think the cat has ever been replaced but from what I've read on other posts it might not make a difference for my situation since it's only failing on NOx emissions. Is that correct?

Since the car failed NOx at 15mph, running it in 1st gear for the 25 mph test "might" bring those readings down but it will still fail on the 15mph test.

Please HELP!!!!!

Thanks everyone.

cas951

You may want to check this thread out.

https://rennlist.com/forums/showthread.php?s=&threadid=110905

cas951

By the way, My car is due for a Smog check too so I'm really curios to your results. Is your car stock with original wastegate? If you still have the original wastegate and the spring is weak the waste gate may be the culprit.

Where in Sj are you?

Mike S

I just failed on my 84 ford van and here's what happened.

My CO readings were almost zero and the NO readings were extremely high. If your CO readings were low and NO high, this usually means a lean mixture. Your catalytic converter will need a certain amount of fuel for the chemical process to take place which removes some of the NO particles.

In your case your readings are pretty average. I'm leaning towards catalytic converter issues on your car. How many miles on the original cat?

cas951

Hey Mike S how's the project coming along? I'd like to stop by and see it.



Efren

Mike S

Efren,

You are welcome to stop by anytime. I finally got the pistons and bearings back today from HPC. See other post. Hopefully I'll start assembling next week (since i'm now unemployed..ha ha aha).

Anyways, just give me a ring before you come over. Email me if you don't have my number anymore.

mike

cas951

Mike, Sorry to hear the unemployment news. The coating looks great. I'll send you an e-mail for the number. I don't have your number.

TonyG

Does your car have a gutted cat or no cat?

You can always put in some stock chips.

Also, try setting the DME switch to the "0" position.

TonyG

Aleks951

Hi guys and thanks for the replies.

cas951 - Yes I thoroughly read through that thread. I also did a search for (smog AND California AND Nox) in this forum so I read the threads that came up as well. The wastegate is also stock so maybe that could be the culprit???? BTW - I live in San Jose down off the Yerba Buena exit from Hwy 101. Are you close by?

Mike - Since I just got the car recently, I can't be sure. However, I checked through all of the paperwork and there is nothing about cat replacement. I would have to assume then that it is the original with 122K miles on it. The PO has a big stack of receipts so I would think he would have had this one too.

TonyG - It looks like the PO just sent me the original chips in the mail. Do you think that might do the trick? I asked the SMOG tech and he said (not that he would know much about Porsches) that he didn't believe that even changing back to stock chips would make the difference.

I know that the PO is responsible for smogging the vehicle but we decided to work together to get this resolved. I really do like the car so I hope the trouble isn't too great to get it smogged.

The cats, from what I can tell, are stock and I doubt the PO would have gutted them. If he were to do anything he would have just replaced it with a test pipe.

Tony - uh......not to seem too ignorant, how do you set the DME switch to the "0" position? I guess I have lots to learn here.

Again, thanks for the suggestions and please keep them coming if you have any.

Tom M'Guinn

The original chips should help if you are doing a smog 2 test. Since when is San Jose a Smog 2 city? Is it? I've been in smog-test-free Florida too long.

Aleks951

Tom - as of October 2003 the Bay Area has been performing the rolling-dyno smog test. The crappy thing is that the smog tech told me that it would have passed without a problem on the old test!!!!

TonyG

Aleks951

There is a rotory switch in the dme the can be accessed from the side of the dme box. This rotory switch lets you "adjust timing and fuel" based on presets within the chip programming.

Turning all the way to the left puts the chips back at the factory position.

You can use a golf Tee and file to a triangle to rotate the switch.

TonyG

Aleks951

Thanks Tony. I think I'll understand more of what you said once I get the box out and swap the stock chips back in.

...unless someone has a pic that might help!

Aleks951

I replaced the stock chips and I found that the DME is set to the most counter-clockwise position. I would think this is the stock position, yes? If that's true, then would that mean that the car was running lean? If setting the DME to "3" (for example) should richen the mixture, yes?

Since my NOx is the problematic issue, would that mean I "might" want to run the DME at "3" to richen the mixture? Would that help it pass NOx emissions?

Or should I just keep it set to "0" (factory position) and keep the stock chips in for the test? Hopefully someone can help shed some light so I may understand this just a bit better.

Thanks for all the tips and now I understand much better the process for replacing the chips and resetting the DME.

Heh, heh..i tried filing down a golf tee but the wood was too flexible at that small triangle size. Instead I filed down a cheap screwdriver so I have this one dedicated (and probably otherwise useless) DME rotary switch tool!

Danno

"So I just took my car to have the SMOG pre-test on the rolling dyno and it didn't pass. It looks like if failed NO at both 15mph and 25mph. "

Looks like you're running too lean and causing high combustion temperatures. The APE chips actually tend to be too rich, so something is amiss in your system besides the chips. I'd check the AFM, sometimes people mess with it in an attempt to increase performance (no free lunch here). Idle voltage on the DME#7 wire should be in the 0.79-0.85v range.

On the FQS, you can use the richer adustments to increase the fuel-mixture to help lower the combustion temperature. You've got a lot of leeway with the HC emissions, so more fuel won't throw you over the edge, but will help lower the NOx numbers.

Be aware that the FQS settings on the APE chips is different than the stock Porsche chips.The AutoThority chips use the following FQS settings:While the stock Porsche chips have the following setting::Due to the extreme adjustments in the APE chips, I wouldn't even attempt to try adjusting fuel with those chips. Put the stock chips in and re-test at the stock #0 position. Then try #1 and #3 positions for +3% and +6% fuel. You might also want to try the #4,5,7 positions with less ignition advance to reduce combustion temperatures a bit as well.

You can look up the FQS adjusting procedure and settings on my RacerX website. Good luck!