I would like to preface this post by stating I am not a mechanic, but I'm not an idiot about cars either.

I picked up an 87 sam last month for $700.  It had been sitting for at least 2 years, but fired right up when I bought it.  It runs pretty darn good, everything works including heater, wipers and so on.

Of course, I tuned it up.  Oil, plugs, wires, cap & rotor, air filter, radiator hoses, fan belt, fuel filter.  The engine doesnt smoke or leak any fluids.  I did the shifter sheets and the tranny bolt replacements.  I thought I was ready for the smog test, but it failed miserably.  Even worse, it was a gross polluter on the 15MPH NO readings.  Here are my readings in ():

15mph, (2106) rpm, (13.7) CO2%, (0.8) O2%, HC MAX 38 GrossPoll 312 measured (234), CO MAX 0.84 GrossPoll 2.34 measured (0.75), NO MAX 859 GrossPoll 2088 measured (2167)

25mph, (2504) rpm, (13.8) CO2, (0.8) 02%, HC MAX 12 GrossPoll 262 measured (188), CO MAX 0.73 GrossPoll 2.23 measured (0.74), NO MAX 798 GrossPoll 1888 measured (1787)

As you can see, it wasnt even close.  I'm not sure where to go from here.  O2 sensor?  cat converter?  Any advice?

Because your hydrocarbons were so high, try checking all the vacuum lines. I'm betting you have a leak...

All the vacuum lines seem to be hooked up.  I cant find any leaks.  Is there a way to test the o2 sensor to see if its working?  I ordered a new one, but not sure if i'm on the right track here.

Put a cat on it all your readings are high. You should also look into egr problems due to your high NOX

   Kevin

Put a cat on it all your readings are high. You should also look into egr problems due to your high NOX

   Kevin

What he said. It's VERY easy to test the o2 sensor with a $3 multi meter - google "Testing o2 sensor". According to the SMOG guys I knew, it was the most often replaced part that didn't need replacement.

Changed the o2 sensor, not sure if it was needed or not but it cant hurt.  Going to clean out the egr and replace the cat next.  Thinking of a carb rebuild too, since its running so rich.  Maybe the floats are bad or sticking?

The way I understand it, the o2 sensor relays info to the computer about air/fuel mixture and the computer then adjusts the carb.  There is no other way to adjust the air/fuel ratio?  Is this right?  Do i need to reset the computer after replacing the 02 sensor?

Changed the o2 sensor, not sure if it was needed or not but it probably won't hurt.

Fixed.

Take it from someone who's done repair work virtually all their life - replacing a part in an unknown working condition, and assuming the new replacement part works out of the box can be a source of future troubleshooting frustration. I'm not a fan of replacing parts which may or may not be working - especially when it takes less time and effort to test the part than to replace it (http://wps.com/LPG/o2sensor.html). But, that's just me. In any case, although the odds are against it, it's important to be aware you may have replaced a properly functioning part with a non functioning one.

Get your hands on a FSM, or Chilton manual. They've got some thorough & easy ways of testing your SMOG system. It'll take you the better part of a day to test everything, but it's worth it. The two most "specialty tools" will be a $3 multi meter, and a $20 vacuum pump.

well, while I guess its possible the new o2 sensor could be defective......theres a better possibilty it aint.  For now, I'll take it for granted the new one works. 

I'll get a multi meter and test it anyway. 

Check you choke, it may be stuck. Mine was. And I don't know where you live but in Arizona you can get a 1 time waiver saying that basically you are working on fixing the problems, but don't have the money to do it right away. So they'll waive your smog test for 1 registration period. That way you can get it registered and driving and fix it up as money allows. This is not something they offer as a solution. You have to ask them about it. And a vehicle can only be waived once in its life time.

The choke is working.

California will not waive the smog.  I have an operating permit that expires 5-31-09.

I went through this heck with a sami that sat 5 years and then wouldn't pass smog in CA.

Here's some reading that could help:
http://forums.turbobricks.com/archive/index.php/t-154414.html

which also references this:
http://www.smogsite.com/calculators.html#lambda 
According to this calc, you're way too lean at both test points (assuming everything else is running perfectly, that is).

No guarantees, but IMHO your combustion temp is too high (not your coolant temp).  This is caused by running too lean or too far advanced timing.

Do the easy things first.  Check that your EGR valve is cycling.  Start the engine and cycle the throttle when warm.  You should be able to see and feel (hot!) the EGR diaphragm cycling in and out in response to changes in RPMs.  If not it needs a cleaning.  Next, samis are famous for clogging the head passage that runs between the EGR valve and the header.  Remove the EGR and inspect for tons of soot and carbon; don't damage the gasket.  Many claim you can't clean this through-head passage with the header installed, but I've cleaned a lot with a fraying length of aircraft cable and a gentle hand.  Then start the engine with the EGR valve removed and see if plenty of exhaust blows out (loudly).  If so, it's clean.
 
Next check your 02 sensor with a DVM.  Also, probe the connector at the ECU to confirm that the 02 signal is getting delivered to it (rules out a harness problem).  You'll need a wiring diagram for this.

Another common cause of high combustion temps is a vacuum leak, which is why everyone's suggested you check for one.  An easy test for a vacuum leak is to probe every possible leak site with the tip of an unlit propane torch (do this outdoors) while the engine idles.  If the RPMs increase you've found your leak.

Another source of too-lean could be a maladjusted carb mixture screw, but that's a PITA to deal with so let's save that for last.

Too-advanced timing could be a problem, too.  Did you replace the timing belt?  Samis are known for running (but not well) with the timing belt skipped one tooth.  Also they wallow out the crank pulley keyway making them un-timeable, so I'd check this.  Also, you didn't mention a valve adjustment, but I'd do one on any new sami I got to make sure that all the valve hardware is properly tightened, as some parts are known to vibrate loose (but I don't see how the valves would cause your smog problem, however).

You can ask a mechanic to check your cat by pulling the O2 sensor and having him wand the tailpipe and then the O2 bunghole.  This tells exactly what difference the cat is making.  I'd bet yours is having no effect on your NOx.

There's also a ton of switches and sensors that the FSM will send you off to test, and any one *could* be the issue, but with the NOx so high, I'm guessing the problem isn't in your control system or adjustments, but in the plumbing (a leak, clog, bad cat, etc).

The suggestion to get a FSM is a good one.
I don't see how a stuck choke could cause high NOx or a lean condition, but I'm no expert.

HTH,

D

Thanks, Thats alot of good info

Hi NOX is typically a cat converter failure.
If it is carbb'd and running rich, that killed your O2 sensor and cat.
a dirty egr is quite possible too running rich.
A simple mechanic with scope can check the carb at the tailpipe to see if it is rich.
have him do a  drop cylinder test, if you have low compression then a cylinder is not burning all the gas, you will fail smog till the cows come home.
If rich try to adjust, other wise rebuild, then recheck.
If then nox are high look at 02 ( check with voltmeter) then cat.
check spark plug wires with voltmeter and plugs, distributor tune-up.

I have a hard time believing it is too lean.  I can smell fuel from the exhaust.  Too me it smells rich, not lean.  Also, there is some dirty brownish-black liquid spraying from the exhaust if you race the engine, mostly when he engine is cold.  I didnt notice it at first, until I had my GMC parked behind it while I was working on it.   

I removed the egr to check for blockage and the passages were clear.  Put it back on and ran the engine to norm temp, and I can see the valve opening slightly when the engine is revved up.  Not sure how much it is supposed to move.

I have checked and rechecked for vacuum leaks and cant find any.  A friend came over and said you can take the cover off the carb, and cover the carb with a cloth to check for vacuum leaks.  He said if the engine bogs down when the carb is covered then you have no leaks.  I had never heard of this before, so I dont know how accurate this is.  But he tried that and said I have no vacuum leaks because the engine bogged down when he covered it.

I have an FSM, but reading it and understanding it are two different things.  Maybe Chiltons would be easier to comprehend.  My gut tells me the cat is bad, could this be why the brownish liquid is spraying from the exhaust?  It aint alot of fluid, but it is noticeable.

Also, when I replaced the spark plugs, they were black...real black.  All of them.

FSM is easier for me to understand than Chilton. FSM usually has more detail & more pictures. Chilton's directions tend to be more generic. But, that's me. What part of the FSM are you having a hard time understanding? Learning how to read that manual will help you diagnose your vehicle (this and future purchases) with confidence anywhere - anytime.