CA Smog Check Failed.
 

I've searched the old threads but it not clear what I should do with my 1987 944 NA. O2 sensor? Adjust FQS? CAT was replaced 2 years ago when previous owner also failed NO. Also I think the DME was changed to a AutoThority chip?
Any help would be appreciated

Here's the results:

At 15mph
Rpm=1795
%CO2= 14.8
%O2=0.3
HC=.22
CO%=.06
NO= 1073 Fai (max is 799)

At 25mph
RPM=1988
%CO=14.9
%o2= 0.2
HC=12
CO%=0.01
NO=1031 Fail (max is 738)

Thanks,
I love this car.
http://forums.pelicanparts.com/uploa...1131327919.jpg

How hot is the car running? NOX that high are usually from high combustion chamber temperatures... Check to make sure you're not running lean.

Yes, it's probably lean. Now that I think about last summer it was running hot with AC on but I never figured out why. What should I be checking?
Thanks,

I'd pull the chip for the test if you can. Chips will commonly pass smog, but they never help you pass.

Besides that I'd be thinking the O2 sensor might be on its way out.

Any other problems with the car? If the car is commonly running hot, it might be worth flushing the coolant system. Lower coolant temps might help a bit.

IanS,
I'll flush the radiator fluid this weekend and replace the O2 sensor. Anything else?

No other problems except for a slight exhaust manifold leak.

Also where can I get a stock chip? for cheap?

If you know anyone locally with a stock chip, you could just swap for a few days. That would be the cheapest option.

Now that I look again, both of your O2 percentages are fairly low, so it might not be the O2 sensor. But the chips are a more likely problem, since you are going to get more power out of a NA car by advancing the timing. I would run a can of good fuel injector cleaner(Techron, Berryman's, BG 44k, etc) as well, since carbon buildup can raise EGTs and NO readings.

Good luck, I went through this a few months back and I'm glad its over with.

switch your FQS to a setting that retards the timing a hair. maybe rich the mixture a bit too. or put your stock chips back in.

Thanks for the suggestions.
When I purchased the car 2 years ago it didn't come w/ the stock chip so swapping chips won't be easy. Unfortunately I don't know anyone to swap with.
Anyone out there in the SF bay area with a stock chip that I can borrow or buy?

Adjusting the DME and a can of injector cleaner sound quick and easy. I will definitely do that.

Thanks again.

I've used the AutoThority chip in two different cars, and both cars passed emissions, so I doubt the chip is causing the problem. As was mentioned previously, high NoX is ALWAYS caused by high combustion temperatures

If it were my car, I would start looking for an intake leak, with the most common source being the injector to intake manifold seals. Next are the intake gaskets, then the J-Boot, followed by various vacuum lines/fittings.

Before you start tearing things apart, check your spark plugs. Any plug that is bright yellow to white indicates lean combustion in that cylinder. Normal running plugs will be anywhere from a tark tan to orange color.

Also verify that the FQWS is in the STOCK position, which, if memory serves, is fully Counter Clockwise. See FRF Wilk's site for more info.

Passed Smog-
 

Hello again,
I just wanted to follow up on my CA Smog problems. It finally passed after the 3rd try but Just barely.

Here's what I did:
Replaced AutoThority Chip with Stock chip from FR Wilk
Adjusted FQS to 4
Repaired loose vacuum hose
Plugs are beige color not white so I didn't adjust the FS.


Final numbers were
15 mph
1800 RPM
HC= 82
CO=.34%
NO=710 (Max=799) Barely Passed

25mph
2015 RPM
HC=35
CO=.12%
NO=591 (Max=738)

Two questions?
1. What else can be done to reduce the NOs for next time? It's so close to the max now. I'd like to know if there anything I can do.

2. When I put the AutoThority chip back in should I leave the FSQ at 4 or back to 0? I normally run premium gas.

Thanks.

As mentioned before Nox is caused by lean condition How about carbon deposits on back of intake valve(s) and in combustion chambers, ususally on top of pistons. The carbon deposit aborb the fuel and lean out the a/f mixture. Make sure fuel pressure is up to spec that would ensure proper workings of fuel pump and fuel pressure regulator. Change fuel filter, cause of insufficient volume of fuel flow at higher RPM. Make sure coolant resevoir cap is working properly, cheap and overlook often. Have radiator rodded to ensure proper cooling capability. Make sure spark plugs, wire, cap, rotor, coil are good. Varify w/ test equipments. Make sure brake, trans, tire are not adding additional load on engine. This might be able to be varified by your gas milage before and after tune up. And always, always change your oil and filter before smog test. HC in engine oil and fuel evap (charcoal canister) contribute to HC reading. Factory service manual section 20 page 8 for active carbon tank for pollutant-free fuel tank venting(layout). Check the vacuum hoses related to this as well. If vacuum hose #11 had a leak the carbon canister control valve will not get the proper signal and would allow canister to purge as well as intro of unmetered air into intake and lean mixture.

I will smog my 951 in about a month or so. I am glad you posted your questions as it gave me an opportunity to look up the systems and review for my own preparation to smog. Good luck.
James

I have an AutoThority Chip in my '87 NA, and the FQS is set to the stock position. Emissions numbers have always been well below the maximum limits.

i bet you need to rebuild your throttle body to eliminate other vacuum leaks. i need to do the same.

Add methanol.