1977 280z prepup for smog check

[rcb280z]

Just google catalytic converter and have fun. There is tons of good info out there.

If you need one you have to make sure it is CARB approved for Ca.

www.hottexhaust.com/californialegal

 

 

In a catalytic converter, the catalyst's job is to speed up the removal of pollution. ... As the gases from the engine fumes blow over the catalyst, chemical reactions take place on its surface, breaking apart the pollutant gases and converting them into other gases that are safe enough to blow harmlessly out into the air.

[240zadmire]

Did a complete tune up based on the FSM.  Went over the fuel injector bible once more time just to make sure.  The Tune Up chapter is talking about dashpot adjustment, well, I don’t have one and mine also a manual tranny.  Another one is to check the CO to have 0.5%.  How do you do that? That is kind of special tool that only shop has?  One more thing.  Adjust BTDC to be 10 degree, my idle is hovering 1000-1200rpm and the screw adjustment on the throttle body is all the way down.  Is there another screw somewhere to lower RPM to 800 base on the FSM?

 

another thing I noticed is the smog on the tail pipe smell like my Honda Odyssey 2014.  Which is no smell at all.  Which I think is good?  Smell meaning I scoop a handful and sniff with my nose.  I know, I know it is not scientific and stupid even, but somebody got to do a dirty work.  
 

what do you guys think?

 

any feedback is great.

 

regards

 

Edited September 3, 2020 by 240zadmire

[Captain Obvious]

7 hours ago, 240zadmire said:

Another one is to check the CO to have 0.5%.  How do you do that? That is kind of special tool that only shop has?

my idle is hovering 1000-1200rpm and the screw adjustment on the throttle body is all the way down.  Is there another screw somewhere to lower RPM to 800 base on the FSM?

Yes, the carbon monoxide percent is measured with a special meter.

It sounds like you're doing pretty good. The only thing that you might still have to investigate is your idle speed and the position of your idle screw. If that screw is all the way down and you're still idling at 1000-1200, it's an indication that you've got vacuum leak(s) somewhere. I suspect it's a bunch of little leaks spread throughout the system. Rubber boots, small cracks in hoses, injector seals, throttle body and intake manifold gasket, etc.

However, at this point, if it runs good and doesn't stink, you might consider taking it in for a pre-test so you know what you're dealing with. Who knows... If you've got some small vacuum leaks and you would be running a rich idle without them, maybe they'll cancel each other out and you might even pass.

[rcb280z]

I recommend getting a "pre-test" done and ask for a print out and go from there. 

Post a copy of it here.

But then again, if it looks like it will pass as its being tested then go for it. 

Edited September 3, 2020 by rcb280z

[Dave WM]

14 hours ago, 240zadmire said:

  my idle is hovering 1000-1200rpm and the screw adjustment on the throttle body is all the way down.  Is there another screw somewhere to lower RPM to 800 base on the FSM?

 

 

 

May also be a defect in the AAR. Bleed air to increase idle at start up. I should close down on its own as things heat up. You may want to confirm its operation per the FSM

[Zed Head]

2 hours ago, Dave WM said:

May also be a defect in the AAR. Bleed air to increase idle at start up. I should close down on its own as things heat up. You may want to confirm its operation per the FSM

One of the first things that 240zadmire did was tune his AAR.  Might need to adjust it back now.  Tuning is an iterative process, often things need to be turned back to where they were.

But before doing that you can just block the AAR hose, either pinch it off or disconnect it and plug it, and see if idle speed drops.  If it doesn't there's an air leak somewhere.

[240zadmire]

All great suggestions ladies and gents.

I just did all those things before jumping on the forum.  I narrowed down to 5 places.

the rubber boot surface cracked but not cracks all the way through. 
 

1.  EGR not 100 closed.   I removed the hose while plugged the 2 ends. Rpm slightly lower.  Maybe  50 rpm.    Blow in one end with great resistance but still some air can get through 

2. hose from the valve cover to body throttle has a tiny leak.  Probably at the elbow where it connects to the valve cover.

3. Don’t know the thing call but the thing underneath throttle body that has screw at the end. Under the throttle body has 2 hoses. One connect to the distributor and the other to the canister.

4.  The throttle butterfly flapper rod might have air sip through

5. the vent under the thermostat body where the hose connect to the EGR breather

 

the oil cap and dipstick seem to be ok. 
 

its going to be something obvious that I can’t get my hands/brain wrap around it.

 

pre-test. 100% will do.  If the car has any of my personality, it will almost guarantee fail.  Just like me. Even while I was I school. I did very well up to the exam point.  The professors has to call me out numerous time slapped my hand why I made such stupid mistakes.  They know I knew the subject but never get 100%.

 

sorry guys but I’m not satisfy/give up just yet, not even for the pre-test. Will need to look from another angle.

 

will keep everyone up to date

 

 

regards

 

 

 

[Zed Head]

Check that AAR.  You adjusted it to give a higher idle when cold.  They don't usually need adjustment, the adjustment screw is glued after adjustment at the factory.  I didn't say anything at the time because it would have just been a distraction.

You might just need to set it back where it was.  Maybe you have fixed some things since then and now your idle will be correct, cold and hot.

[240zadmire]

Will do will do 

[240zadmire]

Hi all

I’ve been so religious lately.  This week alone, I’ve reading bible, well fuel injector that is, couple of time already.  I read, read and reread the high idle section particularly.  Check, test, double check.... I’ve readjust the AAR couple of times a ready, and I don’t think I’ve got to the original factory yet.  I’ve narrow down 2 area that might be faulty.  The AAR and the thing underneath the throttle body.  It calls BCDD (boost control decelerate device) either one or both of these let a little air in.

 

the screw on the throttle body still completely screwed in and now idle is approximately 950.  If the car is fully warm up or rev up a few time.  Idle is 1000 or 1050 or so.  Still not quite yet.  Perhaps I’ll take a closer look at my dead center as well.  Who knows it might be off a degree or 2.

 

stay tune folks. Thanks for all great suggestions 

[Zed Head]

Other vacuum hoses to check are the brake booster hose and the supply hose to the heater valve control bottle.  And the hose to the emissions vapor canister and the distributor vacuum advance diaphragm.  Just pull them off and block the port and see if idle drops.  Some of those arte ported vacuum, so shouldn't affect idle, but they might be connected to the wrong place.

[240zadmire]

Great suggestion about brake booster... will check late tonight.  Garage is 100+ right now and governor asking resident not to use AC this weekend as the heat wave is sweeping the south land.  Will pack the family into a minivan and use it AC instead till 10pm tonight.  Figure smaller footprint should help minimize stress on the power grid

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