L28 02 sensor reducer part? (please help!)

[PhilbertZ]

You don't need to worry about TDC when adjusting the valves; all you need to do is fully unload the valve (cam lobe straight up) and then adjust the clearance.

 

As far as TDC with 0 degrees on the timing mark, the #1 cam lobes should actually be splayed out to both sides equally (neither the exhaust nor intake should be trying to open a valve at that time!). So yea, the cam lobe should be no where near pushing a valve rocker when the timing make is at 0.

 

Thanks - that makes 100% sense (and I did it right, using the FSM method, so...whew!).

 

Going to try and resmog it tomorrow morning.

 

Thanks again everyone here who's chimed in - really appreciate all the good pointers.

 

Phil

[Guest Rolling Parts]

LOL,

It's fresh in my mind. I have an L28 block on an engine stand and I just installed the head and timing chain yesterday. #1 is at TDC and the cam lobes for #1 are "V'd" upwards away from the head....

[PhilbertZ]

So, I took it back to the same test only center and it failed - with higher CO readings than before, and a failing HC reading (I passed this last time).

 

Here's what I got today:

 

@ 15 MPH (1645 RPM):

213 PPM HC (210 is max allowed)- my last test, I passed 181 PPM

3.95 % CO (1.35 is max allowed) - my last test I failed with 2.82 %

 

@ 25 MPH (2663 RPM):

4.34 % CO (1.15 is max allowed) - my last test I passed with with 1.14 %

 

Here's what I did in between the 2 tests (in order performed):

• New plug wires (no new plugs - I installed those a few months ago)
  
• New Cap, rotor
  
• New O2 sensor
  
• Adjusted Throttle Switch (per Rolling Parts' suggestion to spec
  
• New cold start valve connector plug and cleaned terminal
  
• Checked timing/adjusted valves/checked timing again - all within spec
  

I didn't replace the cat...yet. But I am stymied that my readings got WORSE after the "fixes" - at both speeds.

 

I'm at a real loss at this point. I have a list of local shops that do smog and I guess I'll go that route - but it's going to be a lot of money I know....anyone been down that road?

 

I'm now labeled as a "Gross Pollutor" after this second, failed test.

[Guest Rolling Parts]

Well, if you set it into spec and it's worse, then something is wrong with a component.

example: (1)setting the timing with a timing light but the timing mark is off because the pulley has slipped. (2) replacing an O2 sensor with a slightly different style tip that is not heating up enough to give good feedback. (3) doing a cold valve clearance adjustment that adds slop over a previously better hot valve adjustment.

 

Since a Catalytic converter converts CO to CO2, it also might be on the list of items to check...

 

I wish there was a way to test CO/NOx at home so you could step through all the "fixes" to watch if things got better or worse and then figure out why.

[PhilbertZ]

Well, if you set it into spec and it's worse, then something is wrong with a component.

example: (1)setting the timing with a timing light but the timing mark is off because the pulley has slipped. (2) replacing an O2 sensor with a slightly different style tip that is not heating up enough to give good feedback. (3) doing a cold valve clearance adjustment that adds slop over a previously better hot valve adjustment.

 

Since a Catalytic converter converts CO to CO2, it also might be on the list of items to check...

 

I wish there was a way to test CO/NOx at home so you could step through all the "fixes" to watch if things got better or worse and then figure out why.

 

Thanks Rolling Parts - interesting to note, with that logic - I guess I need to find out which component it is.

 

I did the FSM test with the ECU and my ohmmeter and everything seemed to register 0 resistance, so it seems the harness and ECU are good. I guess I need to go back and test component by component.

 

 

has anyone in the SF bay area had their car smog repaired and how expensive was it? There's only so much I can do at home, without test equipment - I'd rather, at this point, just get it done and done right one last time.

[HowlerMonkey]

How long did the inspector have the car idling while waiting........or did he let it cool off for an appreciable amount of time?

[PhilbertZ]

he idled it for about 10-15 before the test. I got it really hot before.

What gets me is that I failed *worse* the second time after all the adjustments...and the first time I didn't get it nearly as hot before the test...

[Guest Rolling Parts]

How old is the CO Catalytic converter?

[PhilbertZ]

How old is the CO Catalytic converter?

 

 

I'm not sure. that was going to be my next move.

 

I'm not sure what limitations I have right now as far as re testing goes (i.e. how many more "tries" I get with the state). Anyone here know, for CA, what those rules are?).

 

I think I'll do CAT install next, check for vacuum leaks, and use some car cleaner for the intake.

 

Any ideas why the HC number would have gone UP with my "fixes" since that initial test?

[PhilbertZ]

Don't forget the catalytic converter. If it's the original cat, most likely needs replacing. This could cause a failure in CA smog test no matter what you do to the rest of the car. What I did was to buy a CA legal cat from Autopartswarehouse.com for about 130. dollars. Since it's a bolt on, I switched the old one on for driving around, then, the new one gets bolted on when test time comes around. This way, the new cat will last indefinitely,lol.

Also, would have been easier to get the female bolt at the junkyard and tossing the old one. Besides, it's free at the junkyard, hehehe. Just finished my strut/suspension rebuild job. I learned a lot tricks, so if you have any questions let me know. I get most of my parts online on Rockauto.com. Everything at Autozone and Kragen is twice as much.

Renatodato

South San Francisco

 

 

Wow...so I did some searching today at Autoparts warehouse, Rockauto and SummitRacing...everything these guys have is 49 state legal. Want to guess what that elusive 50th state is where I can't ship it/use it???

 

Does anyone have a tip for where to get a 50 state legal bolt on cat online, for an affordable price?

[Guest Rolling Parts]

From zc.c:

 

California 1/1/09 - New catalytic converters sold or installed in CA must be designed to meet the following requirements:

1. Must be an OE replacement only - no "high flow" or performance cats

2. Must be granted an ARB exemption

3. No used or rebuilt used cats can be installed

 

If you read further into it you can buy a universal ARB certified cat from places like Catco or Magnaflow. A quick search showed that they have 1977 280z California cats from Catco for $93.47

[HowlerMonkey]

Did the inspector's proceedure include revving it to 2000rpms for around 15 seconds before starting the test?

 

280zx turbos don't have a 02 sensor heater and extended idling can cause the cat and 02 sensor to cool off to the point that they don't do thier job.

 

I'm a virginia emissions inspector and have seen inspectors fail people because of bad proceedure or purposely tipping in and letting off while keeping the mph within the window.

[PhilbertZ]

Thanks guys - I love California but they sure are making it hard to own a car these days-geesh! I'll see if I can track down that cat.

 

Howler - I was sitting in the lobby area but it seemed like he did rev it for a period of 15-45 seconds before the test (after it had been idling for several several minutes. I got it REALLY hot before the test, then he idled it for a while, then did the revving, then did the test.

[renatodato]

Hey PhilbrtZ,

I still say no matter what you do in the engine bay, you will fail CA smog test if the cat is not converting the CO and HC to H2O. The emissions system is a mystery even to the inspectors. You need to go to the "referee" repair shop and they will actually test the car before final smogging it. Depending on the shop and the problem, it could cost you anywhere from 200-1000 dollars. A simple fix is about 200-300. A complicated fix, well.......My suggestion is to double check the timing, and the rpm. Did you change the PCV valve? EGR valve? Make sure your timing marks are right, then, use white out to paint the mark. Disconnect and plug the vacuum advance on the dizzy when checking the timing. Yes, CA has stricter emissions laws, that's why Autopartswarehouse only has one or two CA legal cats. I got mine for about 130 shipped. Also, check the harness to the O2 sensor. These wires tend to get corroded and brittle with age. Don't give up hope,bro. Pretty soon you'll be cruising in your ZX with a smile on your face like me.

Renatodato

[HowlerMonkey]

I'm sure you could buy a cat from a Z31 or 280zx turbo from a person parting the car out.

 

Most will still work if they aren't either burnt through or plugged.

 

They are a lot more robust than the current cats made by manufacturers....but then again, they aren't as effective.

 

Also.....if you take the car to a different inspector and whatever cat you have looks factory, who's to know that it isn't.

[sticky280zx]

If i were you I'd find a "guy" in california to do it for you. Not the best option but normally the cheapest as most guys here in Texas with newer modded cars, do just that. It costs them $40 for a regular test ($15 for us that just have to pass safety) but normally if you throw em $100 they'll make it pass with flying colors, and sounds like it'd be the cheapest option for you.

[Smokescreen]

Hey Phil,

I have been in and out lately, fire season... I had some issues with my '79 car and it failed miserably the first time. I want to point out that it is a "non catalyst" car so I agree that first you might want to strongly consider purchasing a new cat. After that I would look into the Cylinder head temperature switch. It is the sensor next to the cold start sensor. near your thermostat housing. That kept me scratching my head for awhile. It basically adds fuel during the warm up "time" for the engine. This sensor could be faulty and causing the cpu to tell the fuel system to dump fuel well after the engine is warmed up. Yielding rich running at low RPM's.. just a thought. Hope you get it worked out.

Jason

[PhilbertZ]

Hey Phil,

I have been in and out lately, fire season... I had some issues with my '79 car and it failed miserably the first time. I want to point out that it is a "non catalyst" car so I agree that first you might want to strongly consider purchasing a new cat. After that I would look into the Cylinder head temperature switch. It is the sensor next to the cold start sensor. near your thermostat housing. That kept me scratching my head for awhile. It basically adds fuel during the warm up "time" for the engine. This sensor could be faulty and causing the cpu to tell the fuel system to dump fuel well after the engine is warmed up. Yielding rich running at low RPM's.. just a thought. Hope you get it worked out.

Jason

 

Thanks Jason for chiming in here - appreciate the efforts from all of you guys. I'm going to get a new cat and test the PCV valve as well.

 

Jason - do you mean the Thermotime switch? I'll check with the "EFI Bible" again and my FSM on test procedures for these componentns when I do the cat replacement as well.

 

Possibly dumb question: the OEM cat is 14 inches long, correct? there's no risk of getting the wrong size if it's 14 inches long (I haven't been under to measure)? I have seen lengths of 14 and 15 inches in my searches thus far....

[PhilbertZ]

this seems to be the only 50 state legal one I can buy:

http://www.autopartswarehouse.com/sku/Nissan/280ZX/Benchmark/Catalytic_Converter/19801983/DECNIS82511.html?tlc=Engine+%26+Drivetrain

 

Has anyone had experience with this brand? The price seems a little steep compared with the others but if I have no choice, I have no choice....

 

I tried Rockauto, Summit and Autoparts warehouse - any other recommendations before I get this (*only*) choice?

 

Thank you

[renatodato]

Wow, that is a little steep for the Cat. There is a little play on the exhaust end with a telescoping pipe but mine was so frozen i had to cut 1.25" from the cat and re-weld it. You can't cut the ends because of the flared connectors. If you must cut, cut between the flare and the cat itself, then, re-weld. Think of it this way, you'll never have to buy another cat again. Just keep the old one and swap it for the testing every two yrs. It takes about 20minutes to switch them. We get screwed in CA. Why is a cat legal in 49 states and not in one state? Absurd! This is one way to get back at the establishment.

Good luck and keep us posted

PS- I have an 81 280zx ET two seater

Renatodato