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  #16  
Old June 9th, 2020, 10:04
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Re: Ca smog fail. Help!

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Originally Posted by old_man View Post
<snip>

I have never seen a 0% on O2 before. I would call the validity of the test into question.

My '88 was just tested with 0.0 %O2. Mine failed so far due to high HC and CO.
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  #17  
Old June 10th, 2020, 09:53
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Re: Ca smog fail. Help!

Have you checked for exhaust and intake leaks? I couldn't even hear mine an found a small crack in the header. The smog tech(young kid with good hearing)told me to check it.I have had no problems since then passing CA smog laws
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  #18  
Old June 11th, 2020, 19:01
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Re: Ca smog fail. Help!

Sorry- forgot about this post.
I advanced my timing by cutting the ears of my distributor and manually moving it.
Yes this is not a full timing advance as its controlled 1/2 way by the cps. but I barely pass w/ mine on 91. so I move it like 3-5 degrees- worked 3 smogs in a row now
Flame me all you want about this post- but it works danmit. just tricking a computer into running leaner/richer.

Don't go that extreme as ur stock.
get a propane torch/smoke and start checking for air leaks 1st.
aside from that- check basics.
smog checkup on NOX = Ur running lean.

ideas?
Car too hot. (XJ's are notorious for getting too hot to pass smog. I go on a Cold morning First thing AM. Run the car for 15mins prior to heat the cat..)

Cat too cold.
Not enough compression.
Not enough fuel.
U said spark is good. so grounds?

That's all I got lol
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  #19  
Old June 11th, 2020, 20:30
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Re: Ca smog fail. Help!

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Originally Posted by blu3fan View Post
ideas?
Car too hot. (XJ's are notorious for getting too hot to pass smog. I go on a Cold morning First thing AM. Run the car for 15mins prior to heat the cat..)
Notorious - says who? I smog mine in July and deliberately sit and idle to get as hot as possible. Passes with flying colors every time.
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  #20  
Old June 11th, 2020, 20:41
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Re: Ca smog fail. Help!

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Originally Posted by Ronbo View Post
Notorious - says who? I smog mine in July and deliberately sit and idle to get as hot as possible. Passes with flying colors every time.
Lucky you.
In AZ at 117degrees outside. it can be a different story.
I have everything upgraded for cooling and still struggling.. sitting still.
moving I am fine.
seeing 240-260 is too hot for my liking.
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  #21  
Old June 11th, 2020, 22:42
lawsoncl lawsoncl is offline
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Re: Ca smog fail. Help!

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Originally Posted by blu3fan View Post
Sorry- forgot about this post.
I advanced my timing by cutting the ears of my distributor and manually moving it.
Yes this is not a full timing advance as its controlled 1/2 way by the cps.

I'm pretty sure the timing is completely controlled by the crank sensor. The sensor in the distributor is really only used to figure out which stroke it's on.
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  #22  
Old June 11th, 2020, 23:17
Black1990jeep Black1990jeep is offline
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Re: Ca smog fail. Help!

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Originally Posted by lawsoncl View Post
I'm pretty sure the timing is completely controlled by the crank sensor. The sensor in the distributor is really only used to figure out which stroke it's on.
Agree.
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  #23  
Old June 12th, 2020, 11:50
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Re: Ca smog fail. Help!

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Originally Posted by Black1990jeep View Post
Agree.

I would agree.
however-
http://www.angelfire.com/my/fan/dist_index.html
This is how to index the distributor on cams that advance the timing.

It's not perfect. but works.
so like I said. Not 100% of the spark timing. but she wont run at the stock position.
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  #24  
Old June 24th, 2020, 11:34
ljobbins ljobbins is offline
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Ca smog fail. Help!

So I finally had a couple minutes and I threw some sea foam in the intake and got a bunch of white smoke. Some people argue itís good blasting out carbon and others say it just looks cool. Either way itís done and there was a tons of white smoke and with that I discovered an exhaust leak. A perfect looking weld is spitting out exhaust so now I have that to fix next time I have a few hours. Could that be my problem or just part of the problem. Seems like from deductive reasoning that if exhaust is leaving the manifold before it reaches the o2 sensor then the o2 sensor would read less oxygen than is really present and would drop the amount of fuel to the engine resulting in a lean condition. Does that sound right or am I off in my hypothesis? Either way itís getting fixed next time I have time.


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  #25  
Old June 24th, 2020, 18:43
lawsoncl lawsoncl is offline
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Re: Ca smog fail. Help!

The O2 sensor really gives a percentage of oxygen, and not really an amount so loosing exhaust shouldn't affect it. However, keep in mind that the exhaust is not a steady pressure, but rather pulse of pressure and slight vacuum between pulses. So aAn exhaust leak can actually suck air into the exhaust, and yes that can present extra oxygen to the O2 sensor which screw up your NO numbers.
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  #26  
Old June 26th, 2020, 12:33
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Re: Ca smog fail. Help!

I found an exhaust leak once with seafoam. Manifold cracked in a couple of places.


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  #27  
Old June 26th, 2020, 12:39
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Re: Ca smog fail. Help!

So 2 years ago I had similar results with my 88. All good just a bit too high on the NOx @25mph. I ran some seafoam found another exhaust leak. Just a rusty clamp after the CAT this time. Ran some good FI cleaner and adjusted my TPS (yours is not adjustable). Second test passed.

Fix your known leak first.

Then you can test the cat using an IR thermometer to measure the inlet and outlet temps once warmed up to operating temp.
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