WildmaN

So I tried to go in yesterday, for the first time with my slicktop. And failed quite badly. I ran it with all 6 cylinders plugged in. The TPS, and the idle adjusted as high as it would go. Also my EGR is blocked at the line, with electrical tape and the vaccum line dummied over it. Here are the results.

Hydrocarbons (HC) in grams/mile....readings 6.27 limit 3.00 Fail

Carbon Monoxide (CO) in grams/mile....readings 43.61 limit 25.00 Fail

Oxides Of Nitrogen (NOX) in grams/mile....readings 2.31 limit 3.50 Pass

When I got home yesterday after failing. I changed the cap and rotor, unplugged #5 and the TPS, and raised the idle as high as it would go. and EGR no change. Because my NOX actually went lower. And went again today. Here are the results.

Hydrocarbons (HC) in grams/mile....readings 5.83 limit 3.00 Fail

Carbon Monoxide (CO) in grams/mile....readings 96.55 limit 25.00 FAIL

Oxides Of Nitrogen (NOX) in grams/mile....readings 1.39 limit 3.50 Pass

So there you have it. My CO actually shot up much higher like twice from yesterday. So I am thinking my cat might be shot. Because I passed last year with a gutted cat in my '82 T-top. And it passed beautifully.

Any tips, and information would be greatly appreciated. Thanks in advance.

SHADY280

if they dyno it, fill your tires up more. add methyl hydrate to the tank, plug in the tps sensor. use a catalitic, even a temp one. retard timing to 4 deg or lower if you can, it will burn gasses all the way down the tail pipe. keep idle to about 1000rpm. keep #5 unplugged, thats my lucky charm. change the afm to run a but leaner if you can, seems to me like it has too much unburnt fuel.

WildmaN

Yeah I was talking more with my brother. And he thinks possibly the cat, and the muffler, are plugged up. I didn't really think about the muffler causing issues. Also....I have had problems with #6 still not 100%. I think I have stuck rings, from it sitting. It is freeing up more and more. But still not burning all the fuel that goes into it.

So I took the cat off of my T-top. Because I thought it was gutted. Well it is functional, which I thought was crazy. It looks pretty good inside, so I should do better with it. So with all that...I decided to take the back half of my exhaust off of my T-top. And put it all on my slicktop. Because that worked, and I got through smog before. Probably continue tomorrow on it. When there is daylight, too dark now. Besides all that....I always loved the way my exhaust looked and sounded with my T-top. Plus the fact...it has a glass pack muffler on it. Which has less restriction, and nice sound.

So with the TPS, keep it plugged in? Hmmm...I thought unplugged was better. Okay, I will probably try that trick. When I don't pass, with another trick I did in the past. Thanks for the input, keep it coming.

Here is the thread I mentioned.
https://www.zdriver.com/forums/280zx-s130-forums-77/results-my-diagnosis-zguru-18010/

Then here is the other thread, with my passing results. I did this trick in 2007. And it was done with a gutted cat. And it blew pretty clean.
https://www.zdriver.com/forums/280zx-s130-forums-77/i-passed-smog-18094/

evandubya

I'm so glad I don't have to worry about that crap, hang in there you'll pass it soon.

PurePontiacKid

Catalytic was the magic charm for me, all I had to do was put a new cat on (never had one before) and I didn't even have to touch the engine to make it pass! and that was with worn out cap/rotor/plug wires.

ZguyECV

Man that sucks bro. Good luck with the tricks and swap out. Hope you pass the next time trough Good luck!!!

duckyz

Hmmm... Didn't have a problem with mine here in Cali. It actually passed with flying colors. The only thing I did was unplug my cold start valve. When it's plugged in, it stays open and damn near floods out the engine at idle.

WildmaN

Well I found the problem. The cat that was on the car, is hollowed out. Previous owners must have gutted it. So that concludes that my muffler is plugged up. So that would cause my emissions to be high. So I'm swapping the entire exhaust out of my T-top. Also the cat off of it, is really clean inside. So it should pass and run 100 times better. Going back out there to tackle it some more.

SHADY280

good find wildman!!! your gonna have more power, better economy and pass all at the same time

WildmaN

Thanks Shady! Yeah he really moves along pretty nicely. And sounds 100 times better. A nice deep roadster sound. I sure have missed that. Yeah I should pass, pray for me guys. I am going to try again tomorrow. If don't pass, I know that I will be close. I'll keep you all posted as always.

WildmaN

Well, after changing out the entire exhaust. And leaning out as much as I could. (getting the sweet smell out of exhaust) I failed again, but much closer this time. I only have one, to get within the limits. And I believe putting a newer cat, will probably do it. Here are the results.

Hydrocarbons (HC) In Grams/Mile... 2.12 limit 3.00 Pass

Carbon Monoxide (CO) In Grams/Mile...39.26 limit 25.00 Fail

Oxides Of Nitrogen (NOX) In Grams/Mile...1.51 limit 3.50 Pass

Previous Readings

Hydrocarbons (HC) Grams/Mile...5.83 limit 3.00 Fail

Carbon Monoxide (CO) In Grams/Mile...96.55 limit 25.00 Fail

Oxides Of Nitrogen (NOX In Grams/Mile...1.39 limit 3.50 Pass

So there are the results. This was after swapping the entire exhaust out of my '82 T-top. Which passed last year, so I thought it would help. It did, but I believe the cat is not quite clean enough to pass. So I have one, I used only once. It is a Magnaflow, and take it to an exhaust shop. And have it mounted, then hopefully I will get through. Any comments, or tips are still appreciated. Thanks in advance.

Here are the the things in the pamphlet, that tell you what to look for. This would be for (CO) only.

Canister purge system malfunction

Carburetor Malfunction/adjustment (high float settings; leaking power valve; faulty worn or improper sized needles, seats or jets.

Throttle body or ported fuel injection system malfunction (fuel injectors, fuel lines, fuel pressure, injection pump, injector timing)

Engine/Fuel Control System (computer malfunction (system sensors, actuators, CPU)

Improper engine coolant mix, improper or malfunctioning engine thermostat.

Do you think because my engine is running a little warm. I would fail the CO? I am going to change the thermostat out today with a new one. I had an old one on there, from a Turbo.

NismoPick

Did you bring down the timing? Low timing and a clean cat will almost always get you to pass.

And the hotter the engine, the cleaner it will burn. I always take my car for a nice freeway cruise to the next exit and back, then drop off the car... the engine MUST be at operating temp.

Also, I go to the same shop every time, so the guy knows me & now lets me run the emissions test in monitor mode to see the results... that way I can adjust things live, and know how it will do in the official test.

WildmaN

No I didn't bring down the timing. I'm sure the cat is pretty clean. So just lowering the timing, will burn it cleaner? And yes the temp was actually above operating temp. My thermostat was stuck open. I just replaced it tonight with a new one.

I wish I had that luxury, of hooking it up to a machine, and dial it in. You are lucky to have that pleasure, and convenience.

All aside...I also noticed my charcoal canister's filter is missing. Would that make any difference?

NismoPick

Just retard the timing... you should pass. That's the first thing you do when a car fails emissions.

The shop I go to is a small "out of the way" struggling shop... I shoot the breeze w/ the guy, give him some business, and he's coo.

WildmaN

How much should I retard the timing? So you think after I do that. With what my readings show, I should pass? Anyway tell me how many degrees. I have it set at 8 degrees. Which is factory specifications.

SHADY280

retard the timing as low as it will go, close to 0 deg. then bump the idle up. what i always do is use a sharpie to mark where your at now so its easy to put it back. add methyl hydrate, it will also dramatically lower the co as well. i cant remember if you already did. your so close it hurts.

BlueKitsune

I'm glad I don't have to deal with that junk. I'd be so screwed. I've seen this chem you add to your fuel that says "Guaranteed to make you pass!" Maybe see if you can find that stuff? lol

WildmaN

Thanks for the feedback guys. I got some stuff, called pass emissions. And I am going to retard the timing. And try again tomorrow. I'll keep you posted.

WildmaN

Ok guys, I have a problem. I went out and marked the harmonic balancer. And then proceeded to retard the timing. And it is all the way to the left, and wont go any lower. And it is at 8 to 8 1/2 degrees. I find that, really strange. Anybody have any pointers?

NismoPick

So what was the timing at before you retarded it?

WildmaN

Never mind guys, I figured it out. I grabbed another spare dizzy, I had lying around. And noticed the plate on the bottom is adjustable. There is a 8mm bolt on the bottom. I retarded it to like 1 1/2 degrees. lol It still is running okay. I'll keep you posted.

Oh, and timing was 9 degrees, before I retarded it. As stated though, I figured it out. Now I am hoping I run leaner.

SHADY280

yeah that plate ads some extra movement, handy sometimes. good luck wildman!!

WildmaN

Well after leaning it out, the best I could. Retarding the timing to 1 degrees. Which I set it 7 degrees less. And cranking the idle all the way out. I actually did worse.

Today's readings

Hydrocarbons (HC) In Gram/Mile...2.58 limit 3.00 Pass

Carbon Monoxide (CO) In Grams/Mile...43.15 limit 25.00 Fail

Oxides Of Nitrogen (NOX) In Grams/Mile...1.89 limit 3.50 Pass

Previous readings.

Hydrocarbons (HC In Grams/Mile...2.12 limit 3.00 Pass

Carbon Monoxide (CO) In Grams/Mile...39.26 limit 25.00 Fail

Oxides Of Nitrogen (NOX) In Grams/Mile...1.51 limit 3.50 Pass

What's crazy, is everything went up, since the last test. And it is supposed to run leaner, with the other tricks I mentioned I did. And what you guys told me to set it at. It just plain sucks!

Well there you have it. I have to give up, and take it to a shop. And spend money, I really don't have. I am so sick of this BS! It's freaking stupid! I am just venting, pay no mind. I have been having a bad day. Plus the fact, my Z is overheating.

feifongwong3

Just move to texas where z drivers don't have to go through that smog/emissions crap.

NismoPick

Did you ever check / replace the spark plugs? Old / dirty / fouled / out of spec plugs can cause random misfires.

Were the RPM's jumping around at idle? At speed? Classic sign of misfire...

You mentioned that cyl# 6 was having problems... was it cyl# 6 that you had disconnected? Is it still having problems? Is there any colored exhaust?

After reading through all your posts, you've "adjusted" a lot of things, most not to stock spec. I suggest doing a tune-up: cap, rotor, plugs, make sure sp wires are secure & aren't arcing, pcv valve, vacuum lines all secure, etc. Compare all 6 spark plug tips to see if one cyl looks different.

For the retest, set timing to about 5 degrees, run all cylinders, set idle back to stock, make sure engine is hot (just returned from a cruise on the freeway), and if you are going to run any gas additive, burn it through the tank & refill... most additives will actually hurt emissions.

And if you are going back to the same shop, ask the guy if you can run it on the test / monitor mode first (offer a burger or $10...).