Foz

Getting kind of bummed about the whole thing since I've spent a ton on this car trying to get it registered (back reg fees & penalties, new battery, new catalytic converter, new O2 sensor), and am still getting nowhere.

Car: 1987 NA 944 (~200k miles)

1st smog: Got it warmed up hot, took it straight to the shop. These results didn't count since it wasn't a test-only shop, but I wanted to get a feel for how the car would do. It failed on HC & NOx, but not by much (sorry, I don't have these results, but they are basically the same as smog #2 below). The smog guy said to get it really hot and go try at the real station.

2nd smog: I got on the Rennlist forums, and was reading about how to pass with a little "chemical enhancement" (acetone, ethanol, methanol, etc.). Ethanol seemed like the best choice, so I drove the car down to about 5 gallons of gas, then threw a gallon of Home Depot ethanol in the tank, drove around for 30 miles of twisty roads to mix it up and get the car hot, and went straight to the official test-only station. Results are below:

15mph: CO2-13.98% O2-0.97% HC-92 (Pass:83) CO-0.23 (Pass: 0.53) NOx-950 (Pass: 663)
25mph: CO2-14.30% O2-0.63% HC-82 (Pass:65) CO-0.27 (Pass: 0.63) NOx-857 (Pass: 738)

3nd smog: It seemed that the ethanol concentration wasn't high enough, so I drove the car until it ran out of gas, then threw in 2 gallons of premium and a gallon of Home Depot ethanol in the tank (for a total of 33% ethanol blend), drove around for 30 miles of twisty roads to mix it up and get the car hot, and went straight to a different official test-only station. Results are below:

15mph: CO2-14.3% O2-1.0% HC-83 (Pass:83) CO-0.20 (Pass: 0.53) NOx-862 (Pass: 663)
25mph: CO2-14.8% O2-0.3% HC-69 (Pass:65) CO-0.28 (Pass: 0.63) NOx-1152 (Pass: 738)

4th smog: Since it didn't appear that I was going to be able to cheat my way around the system. I had a new catalytic converter put on. It failed (see results below), but at least the HC problem went away. The tech said it was running too lean, and that's why the NOx was too high. After reading through some more forum posts, I tried setting the Fuel Quality Switch to #3 to richen up the mixture, but it had no effect.

15mph: CO2-14.50% O2-0.52% HC-18 (Pass:83) CO-0.01 (Pass: 0.53) NOx-967 (Pass: 663)
25mph: CO2-14.60% O2-0.32% HC-22 (Pass:65) CO-0.01 (Pass: 0.63) NOx-1152 (Pass: 738)

5th smog: The tech thought the O2 sensor was causing the car to run lean, so I bought a Bosch OEM sensor off Amazon and installed it. I don't have those results, but the tech said they were basically identical to smog #4.

I think most of us have had an experience where somehow we end up with a money-pit lemon (maybe not a car, but a house, girlfriend, etc.) and we just keep sinking good money after bad into trying to salvage the situation. At this point, I am out of ideas on what to do next, and am hoping that some of you might know how to escape this mess. The few options I can think of are:

1) Sell it on Craigslist as-is.
2) Take a loss and sell it to the State of California for $1000 to be scrapped.
3) Pop the cover off the air-flow sensor and adjust the clock spring, although I hear that only helps at idle(?).

Unfortunately, my landlord has gotten strict and won't let me park it on the property anymore, and I can't park it on the street because of no registration (It has already gotten towed once). The state will only give me a 1-day moving permit (after I wait in line at the DMV for an hour), so I really have to either get it registered soon or sell it.

Any help would be appreciated.

Thanks,
Foz

kab996

At this point I would try the "guaranteed to pass"stuff that comes in a bottle at the auto parts store. I passed with my 87 NA. It was in good running shape but had no cat. And it passed no problem. I added the whole bottle to a pretty low tank of gas and got the motor realy hot and went strait to the testing staition. I think before you keep sinking more money into the car its worth a try.
Kyle-

944_S_TYPE

Perhaps sell it to a rennlister who lives in a state that does not have emissions inspection. How about cleaning the injectors, FPR's, etc.

Can you pay someone to fix it?

Funn944

I don't know of any "guarantee to pass" stuff that actually works. If there is I need to know. I keep my car registered in another state where I own a house.

kab996

Mine failed first try only change I made was adding the additive and it passed no problem. It even passed with the "quick pass" test. This was in Colorado. The bottle just said guaranteed to pass.
Kyle-

kev951

your last test was the closest. now you need more CO to bring the nox down. very straight forward, you can restrict the fpr vacuume to give you more fuel pressure, which will bring co up and nox down
or fqs swicht to add fuel and timing..

wesmc3

Jeez- is moving out of cali an option? How much is having injectors flow tested and cleaned cost there? Follow with a compression and leakdown (very easy, you can borrow those tools from the autoparts store if you have a compressor.)
You have a new cat(aftermarket cats can be an issue but looking at your #'s that is not causing your fail), I assume good plugs, new O2 sensor, AFM working (or you would have bigger issues that you would have mentioned) so your #'s should be fine unless your mix is really off across the 4 cyls.

Makis

Idle speed CO before the CAT can adjusted on the AFM as it has a screw to adjust the air mixture at idle. Also the AFM has got a spring to adjust the resistance of a flap movement when air is entering the engine. Is possible the spring can be adjusted to give more CO when the engine is under load but this is not a common procedure.
More likely if the engine is sound the problem is restricted injectors or the FPR is not controlling fuel pressure correctly. A fuel pump on its way out can also cause this.

Rogue_Ant

The car isn't that far off passing...

The high NOx is typically due to high-combustion temps. With the new cat, you have a lot of room with HCs, and now need to enrichen the AFRs and remove timing.

If you still have the same 33% ethanol in the tank, then I would run the FPR without a vacuum line (plug the line), then also switch the FQS all the way to position 5 or 7. This will add quite a bit of fuel, and pull ~3° ignition timing, both should help bring down NOx.

Obviously, this setup is for emissions-purposes only.

87 944 C

if you wish to sell the car, i may be interested, but before that:

NOx is caused by high engine temps...so running the car till its really hot may be whats causing the issue. how's the coolant, hoses and thermostat?

Litesonic

FWIW, mine had the challenge of too rich... exact opposite. I had to pull fuel via the FQS to get a more complete burn.

Along the way I tried everything else, including replacing the cat.
I paid for and had installed a new aftermarket standard (not racing) cat... it still failed.
Put back the OEM, 25 yo. 300K cat... it passed (with the right AFM)

Love living here, despite the smog hassles.

nasty9er

did you use Fuel HEET as your methanol additive?

i have to the end of the year befor i have to worry about the DMV but its always in the back of my mind after last time with my other car (8 trys 8 fails now it sits)

in my state there is there are 2 ways around it one is a 10% or 15% improvement and the other is putting 50 or 100 bucks into emission parts and bringing them the receipt

i would see if they have any thing out there like this. just an idea good luck

gtroth

Couple of thoughts-
1) borrow a known good afm. If yours is lying to the dme, dme will set fuel wrong.
2) what is your fuel pressure? Dme might be setting the fuel right but can't happen (clogged fuel filter)? Maybe fpr but I think they usually fail high-pressure which would err on the side of rich. Measure pressure and know.
3) witchhunter your injectors. Same idea as (2) except clogged injectors
4) any idea if there are any vacuum leaks (dme knows nothing about unmetered air so won't provide the fuel for it)?
5) good, correct, properly gapped plugs? Not sure how that might interact, burn hotter or something. But if it were me I'd make it so nonetheless.
Good luck.

odurandina

that's what happens to 25 year old cars born under California's strict smog restrictions, etc.

2 options are;

1. engine rebuild, new fuel injection system, sensors, etc, new smog pump (CA), fresh cat and you'll be right there.

2. sell it in another state and buy a late model sports car.

3. send a letter to the CA EPA Air Resources Board informing them the your tiny, fuel efficient 944 will be replaced with a Hummer 2.

Foz

Woohoo! Passed after 7 tries. Here is what I did:

First off: Disclaimer:
I am a cheap & lazy bastard. The right thing to do would be to check the FPR, injectors, timing, blah-blah-blah. I would probably have a perfectly tuned car, but honestly, I'm lazy. I'm probably not worthy of being on Rennlist, but whatever - I'm here anyway since this is the best resource for 944's along with Clark's Garage.

So I popped off the cover of the AFM, and adjusted the clock spring by 2 notches while the person who installed the new cat watched on his 5-gas analyser. Not enough. So we went up to 5 notches - Bingo. Unfortunately, he is not a "Test Only" station, so he couldn't do the official test. So I drove to a couple of Test Only stations, but since it was late on Saturday, they were all booked up. So I finally found one that only had one car ahead of me, but still it was a 20 minute wait. So I kept the engine idling to keep the cat hot. This was smog check #6:

GROSS POLLUTER!!! YEAH!!!
15mph: CO2-14.0% O2-0.0% HC-160 (Pass:83) CO-1.95 (Pass: 0.53) NOx-0 (Pass: 663)
25mph: CO2-13.4% O2-0.0% HC-177 (Pass:65) CO-2.89 (Pass: 0.63 - GP: 2.13+) NOx-0 (Pass: 738)

Clearly, we'd gone a little far with the mixture adjustment from the land of Lean to the land of Rich. I went back to my cat guy on Monday to readjust it, but he said he was too busy, and just to adjust the AFM a couple of notches and get it retested.

So I went back to the Test Only guy who was a cool dude, and agreed to let me tweak it on the dyno. I put it back to +2 notches on the AFM (down from +5 notches), but it was still failing for NOx. So I bumped it to +3 notches and he agreed to run the test in 1st & 2nd gears instead of the usual 2nd & 3rd gears (but have to keep the RPMs under 3000). Result: PASS (actually a pretty good pass).

15mph: CO2-14.6% O2-0.0% HC-38 (Pass:83) CO-0.02 (Pass: 0.53) NOx-133 (Pass: 663)
25mph: CO2-14.7% O2-0.0% HC-28 (Pass:65) CO-0.01 (Pass: 0.63) NOx-44 (Pass: 738)

So here is what I would have done differently, if I had known everything I know now:

1) I would have saved myself $100 and not replaced the O2 sensor. Apparently it only makes small tweaks to the air/fuel mixture and changing it won't save you if your mixture is way out of wack.

2) Had the tech test it in 1st & 2nd gear. That helped a lot with HC & CO.

3) I wouldn't have bothered with the 33% ethanol, but only because my problem was that I was too lean. I have a feeling that the extra oxygen in the ethanol would help with HC & CO, but since my problem was NOx, it didn't do squat.

Hope this info helps someone else. Thanks for all the replies and suggestions. BTW, I am selling the car, so '87 944 C' - I will PM you.

Foz