from one thing to another: time to pass CA emissions

[cerberusaardvark]

thanks to the help of this forum ive brought y tired 4.o from the brink of death back to life. my other thread about engine knock after my rebuild has ended successfully and now its time for the next hurdle: passing CA emissions.

today i went to get a smog and failed the emissions portion. heres my numbers

hc-measured - 148 @ 15mph 110@ 25mph
max- 61 36

no- measured- 676@ 15 pmh 734@ 25 mph
max- 350 527

i passed the co

so... as you might know from my other thread, all the most common problems with old ignition and air filter hardware is new and clean. running 91 octane.

however, my cat is 20 years old. my car does smell strongly of emissions but not quite like rotten eggs or sulfur. is there anything i can add in to the engine to help out? i know most of that stuff is just high octane fuel risers.

i wish i was closer so i could wait or take it to another place but im pretty high over.

 

[Anime]

There have been a few other CA emission threads in the first gen forum lately, and the other posters passed emissions once a new catalytic converter assembly was installed.

Worth noting though, that a rebuilt engine will typically put out worse emissions until it breaks in, so there's a chance that the numbers could come down some over time, but you probably don't have the time or ability to break it in and then get it checked, so a new converter might be the solution.

It's also possible the readings are off or wrong, plenty of vehicles that fail horribly at one testing facility mysteriously pass without an issue at another. Might be a case of not tipping the tester enough before the test and so they deliberately make it fail until you get the idea of what it takes to pass.

 

[L.A.X]

I just went thru the smog process. Change plugs, wires, oil, clean your maf, throttle body, and sensors. Check to make sure all vacuum lines are connected correctly. Clean your fuel system with Chevron Techron concentrated fuel system cleaner.

 

[cerberusaardvark]

good point. those numbers were soo bad i was flabbergasted. ill run it around and hopefully the emission will calm down. how long does a normal engine break in take? it was only a top end rebuild...

also i did it at a 76 station just bc it was the closest. i figured the cat could be suspect but is there a definative test to know for sure? i searched and found jsut as many peopled who ended up wasting money on a new cat as people who benefited

 

[Jason94sport]

Look at it this way...It's a 20+ year old catalytic converter, using 20+ year old tech...They don't last forever.
If your having emissions issues that's the most likely culprit....& if it's not, replacing can only benefit you down the road.

 

[L.A.X]

High NOX readings usually means bad cats. Make sure your EGR system is working properly

 

[Anime]

Even if you just rebuilt the top end, the break-in of new parts and the chemicals involved plays a part in what comes out of the tailpipe. Sometimes it's just a few thousand miles and an oil change before things settle down, sometimes it's much longer than that.

The only way to know for sure would be to get it tested at another location, if it fails with about the same numbers, you should replace the converter assembly. If it passes or at least has better numbers, you might be able to do some cleaning and make it pass. Look up tips for passing emissions, stuff like using top tier gas, being sure the engine is warmed up and at operating temp immediately before the test - but not just from idling for a long time. Best thing is to pull in right off the road from driving and into the test bay.

You can get a new CA-emissions converter assembly from Advance Auto Parts, using their $50 off $125+ online coupon, and it'll be shipped for free. If the converter is in bad enough shape to affect emissions, it's probably in bad enough shape to be a restriction. You might save whatever you spend on a new converter back in getting 2-3 MPG back in mileage, and a restoration of power and torque.