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Discussion Starter · #1 ·
I took my truck in this past weekend for a smog check and failed.
The guy said i just needed a tune up. I'm wondering if the fact that my
tail pipe broke off the muffler(i rigged it back up, with tie wire, but...)
could have anything to do w/ it (not sending enough "emissions" for the machine to read?)
Any suggestions? Serp, you out there??????????????

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Discussion Starter · #3 ·
if were only that easy! /images/icons/crazy.gif

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Awe poor guy, hang in there. One day you be driving a shiny SD/images/icons/laugh.gif Mine/images/icons/wink.gif
 

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Do 3 things and I can almost guarantee you'll pass. First, get an oil change. Second, lower fuel mixture if you have carbs so that it's barely idling. Lastly, pull your breather cap from the valve cover and look at the bottom. Punch about 10 holes in the bottom going around the stem that sticks into the valve cover. This allow exhaust gases to pass over the cover instead of going back through the system and out the exhaust.

I get an oil change and take 5 minutes to lower the fuel mixture and pass every time. My 77 Suburban passes so easily I'm surprised they don't question it.

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Discussion Starter · #6 ·
Thanks Third. I'll give that a try.
(nothing like waiting till the last minute to do things/images/icons/crazy.gif)

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If that doesn't work - Call me!
I work on Racecars - EIGHTEEN YEARS!!!
Special WHAT?
OH Inspection License-
O Yeah - I got all that $hit Tough Guy!


 

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<blockquote><font size=1>In reply to:</font><hr>

Serp, you out there??????????????

<hr></blockquote>

LOL....always.
I wasn't going to open this post ( something about a truck ) but it's 5 AM and I'm bored.
What Third said about the fuel mixture will work as well as retarding the timing, they're measuring the by-product spent fuel so if you lean it out there's less fuel to burn and set the timing late it goes out the exhaust before it has a chance to burn completely.
It will run crappy and smell bad but will pass emissions.
The tail pipe thing would only help you as clean air leaks into the exhaust.
As to the other two sugestions, I don't see how changing the oil will help but that's never a bad thing.
I would be careful about altering the PCV system there's a reason why explosive gases are drawn out of the crankcase, those gases build up during normal operations and one spark however unlikely and you've got a bomb under the hood.
Better to plug the hose or disconnect it for the test so it can be returned to normal afterwards.
PCV stands for positive crankcase ventalation meaning the gases can only go one way so if you experience a back fire the PCV valve closes to prevent the flame from reaching the crankcase.
Bet you didn't know every gasoline engine out there is a baby Hiroshima on wheels./images/icons/crazy.gif

 

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You need to be careful not to lean the mixture enough to cause the engine to miss or the HC will be too high, even though the CO passes fine. And changing the oil can help because the gasoline in the old oil (if you really drive a roach) gets sucked through the PCV system, effectively richening your mixture. Retarding the timing is also a good suggestion. You might also try raising the idle speed to just under the maximum allowed. Is your air cleaner really dirty? That can raise CO just enough to fail you.

 

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Serp, ever see the aftermarket breather caps that don't have a line going back to the air cleaner? They have the holes around the bottom and are considered safe. This is doing the same thing but retaining the stock appearance. Mines been like that for the last 7 years.

As for the oil change, it helped mine. I failed miserably one year and someone suggested it. It worked. Here in AZ they measure carbon monoxide and hydrocarbons. Oil that is too old will raise the carbon monoxide, apparently. Don't know the details on that, just know it helped from experience.

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I used to drive a 1978 Ford wagon with a big ol' 460 motor in it. It got like 7 mpg... but only if I drove like an old lady/images/icons/crazy.gif.
Every time I had to go through emissions, I would drive close to the testing site, pull over and pop the hood, and just pull the PCV valve out of the top of the valve cover and go get tested. You could actually see exhaust coming from the hole. Worked like a charm every time. Passed with flying colors.
I don't know what kind of harm this would do if any, but on a '78 Ford wagon, you think I cared?/images/icons/smile.gif

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<blockquote><font size=1>In reply to:</font><hr>

Serp, ever see the aftermarket breather caps that don't have a line going back to the air cleaner? They have the holes around the bottom and are considered safe

<hr></blockquote>


Yeah I saw lots of those, Chevrolet used to put one on each valve cover on their 283cid motors with something like a brillo pad inside. I also saw a few come into the shop with the valve covers blown off and the bolts still in place.
Like not wearing a seat belt you could drive for years and be fine but if and when it blows you'll know it by the bang and the dimple in the hood.
It is less likely these days because todays engines are more efficient and run leaner than the guzzlers of the 60's and 70's but the potential is still there.

 

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Mine is from the seventies (late 70's). Anyway, I asked someone in the know why the oil change was such a help. If you let your oil go too long, it gets contaminated with fuel and adds those contaminates to the overall numbers at emissions testing. I know there's a better way to explain it but this is lay-terms.



Forgive & forget. Just never forget when I forgive.
 

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<blockquote><font size=1>In reply to:</font><hr>

If you let your oil go too long, it gets contaminated with fuel and adds those contaminates to the overall numbers at emissions testing

<hr></blockquote>

That makes sence. When the gases get past the rings they mix with the oil in a wind vortex.
Muscle cars with Chrysler big blocks would use a windage tray in the oil pan because it was found that 1 quart of oil would remain suspended in this vortex.
If the oil is clean it would act as a filter absorbing contaminants but when saturated all contaminants and unburnt gases go out the PCV system and back through the intake to enrichen the incoming mixture.

 

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Discussion Starter · #15 ·
I knew you were out there, somewhere!/images/icons/smile.gif
It's a 95 Dodge, and I'm 99.87% sure it's injected, so messing w/ the
mixture is out (isn't it?). As for taking off the PCV cover, I'll try that if i fail again.
I changed the oil, plugs, O2 Sensor, and cleaned and oiled the air filter (K&N).
I'm gonna take her back tomorrow w/ an extra 20 spot, just in case /images/icons/wink.gif
Thanks again.


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Discussion Starter · #16 ·
Well, i took her in today and she passed!
Thanks again guys!

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