4.3L V6, Emissions failure, 1986 Caprice, Parissiene

Car went from being very clean to failing emissons in the last 20K miles.
Two years ago, had the dealer replace the oxygen sensor, put new plugs,
air filter, pcv valve and this brought it into passing. This made it pass, but it was no where near as clean as the previous test cycle. The catalytic converter was replaced 25K miles ago at the dealer with oem new stuff. All the emissions stuff is connected.
Car has 200k miles. Doesn't burn much oil, but does leak some oil down the valve stems.
I don't think there are any vacuum leaks.
Car doesn't idle quite as nicely as it used to.
What is the most likely suspect causing emissions failure on this car?
Thanks
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OIL LEAKS DOWN THE VALVES? Is it normal to bleed from the mouth?

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Do some of you make this up to get a rise from us or has it occurred to you all that valves are for gasoline intake and exhaust removal and unless you have (nope) a diesel they don't DEAL with oil much? Have you got a nasty case of blow-by? When was the last time you checked your rings? Did your mechanic even look?
I'm mildly flabbergasted. HUH...whatever.

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The engine is old and with mobile one oil, it puffs on start up only occasionally. It depends on how long it's been parked, weather its on a hill and that sort of thing. It's done this for ten years and is no different lately.
Yes, it is normal for this engine with this milage. It's no different now than when it passed emissions with flying colors.
I could use some help here instead of sarcasm. Thanks.
Steven Dinius wrote:

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I don't think it's normal or you wouldn't ask? We have scads of FI 4.3 Blazer 4X4's in the area and they get beaten up far worse than yours. Don't accept that it's the status quo. If you've got oil leaking into your valves, it still sounds to me like your rings are worn out. ESPECIALLY at 200K. Sarcastic, sure, but I'm only flabbergasted bcuz this seems like common sense to me--it has to be looked after even more after 100-120K. Not to mention it's seventeen years old. I have a 1986 2.5 four and don't I know that (I have only 114K).

plugs,
The
down
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A 4.3 V6 is effectively a 350 small block missing two middle cylinders. Small blocks are notorious for puffing a bit on startup after sitting; it's not a catastrophic situation, and, assuming the smoking desists after a few moments, is not an indication of piston ring/bore wear. Rather, it typically indicates worn valve guides/seals. Worn rings would cause oil smoke emissions continuously and to a more severe degree with the hammer down. Posting the ppm and % numbers from the emissions fail report would indeed be helpful.
As for Mr. Dinius and his 'common-sense'-induced flabbergastedness, methinks his muffler bearings are binding and causing his Johnson rods to bang into his lugnuts, so to speak. Let's all sing to the tune of RawHide:     "Trollin', trollin', trollin'      keep them trolls trollin'..."
On Wed, 12 Nov 2003 22:40:08 -0700, Steven Dinius wrote:

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On Wed, 12 Nov 2003 22:40:08 -0700, Steven Dinius wrote:

Not much on the common sence then are you MR. Dinius. Lets see, oil leaking onto the valves. Sure, it does happen. Now Rings worn out. Yep, that will happen too. BUT, the rings worn out CAUSING the oil to leak onto the valves? Well, lets just say it COULD cause a little bit of that IF the rings were worn out enough to be letting enough back pressure into the crank case to push oil through the valve guides and seals, AND the pvc valve is completely stopped up AND ALL of the gaskets sealed pressure 100%. So basically, that is NOT the problem.
So basically, the little bit of smoke at startup is more that likely caused by worn valve seals, assuming that there is only a small amount of smoke that goes away really fast.
Joel
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i got the hint in mr dinius replies that he is a complete MORON....]
oil smoke at strartup is a common thing in these motors, such as in the small block chevy's
"JOLA" <None> wrote in message

leaking
will
crank
caused
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I'll second that!
--
______________________________________________________________

Dennis Smith
  Click to see the full signature.
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says...

It would appear that Mr. Dinius' sole purpose as a new entrant into these NewsGroups is to see how many posts he can make in the shortest period of time. EARTH TO MR. DINIUS - We want quality of posts, not quantity of posts in these NewsGroups!!! If you have nothing to say, please remain silent!!!
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bulls--- or I would've made a lot more. I had a couple of guesses, and if I'm wrong, so be it...
PS I've been here 4 months I believe.
I Really love FBR's spam-warrior zealotry. He's been right 97.3 percent of the time. But he's still somewhat of a self-righteous twit. Rivals me! I don't know what Pontiac model HE owns, but I did ask a good q. about my 6000 and got little if any fervor. If you are a matter-of-factly group, fine. I don't have to fix my car every day. And by asking some occasional dumb questions (not the only one here), I'm actually LEARNING stuff. Some of you assume this is GM Goodwrench Clinic and get bent by the same dumb q's and why don't they read before they post?
Because the posts are being dropped at a regular rate by the server, duh, and cuz more people are trying to fix these cars so they come without knowledge!
The characters and types I've encountered in this group aren't any different than any other group I've seen. Implying that I register less than adequate intelligence is really swell. You look great there.
Hopefully somebody WILL find out what's wrong with the damned car. I'm not a mechanic. My dad was. My mistake for not taking it up.
GM group removed.
says...

posts
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reveals that you wander around from NG to NG irritating everyone with your asinine comments. This is evidenced by the attached Google Link which shows 118 posts under this name alone and gawd knows how many other trolling aliases you have! A quick view of several of your posts says it all! A quick warning to regulars to the Group, don't waste a lot of time reading Steve's posts because they are basically all the same. They lack substance, say nothing, and only serve to irritate members.
http://www.google.ca/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22Steven+Dinius%22+&btnG=Google+Search&meta
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The only ass is U. I don't care one way or the other if you fart around looking for my posts <hah> Does that make you proud?
Steven Mark Dinius 416 NE 3rd St Ontario, OR 97914
DOB: 06-26-66 Nampa, ID
you're in Canada
I repeat U are still an ass
former tags: snipped-for-privacy@cyberhighway.net, snipped-for-privacy@fmtc.com, snipped-for-privacy@fmtc.com NO suspensions for any reasons--changed ISP and dropped accts when money was low.
I ain't no damned troll. I am bipolar. Diabetic. Hypertension. Cholesterol. Arthritis. Sick of idiots hastily calling me an idiot. F--- you. Look in the mirror while you chew on your toast. You ain't Jesus either. Bark without thinking. You got a block setting. Use it. I am not anonymous nor did I create a false tag that would bounce back with <550 User unknown>. And maybe not too happy about my relationship falling apart. Sorry if it gets in the way.
Did you have fun?
Sheesh.
reveals that you wander around from NG to NG

the
members.
http://www.google.ca/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22Steven+Dinius%22+&btnG=Google+Search&meta >
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Perhaps you could inlcude the test results with this posting so everyone can see then specific question such as HC is out of limit at idle or at certain rpm. It is diff to offer suggestion.
Cheers, Mnn

plugs,
The
down
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I'd suspect the valve guides/seals. Sad part is, minor oil consumption can kill the cat over a two year period. (ask me how I know). However, it would help to know the actual readings - what failed, HC, CO, or Nox?

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Well put, I need help not sarcasism.
One guess is that the intake manifold gasket might not be sealing, allowing oil to enter intake runners. This is at best a guess. Chevys are known for intake manifold gasket failure, usually accompanied by coolant leakage.
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