failed 4th time!! i'm going to burn this car!

 

Too bad you don't live in North Carolina (I'm in Charlotte). All non-OBD II cars get just a safety inspection. No emissions as of last year - AB

 

I'm sorry to hear that the car didn't pass the test after 4th attempt.

Now let's get back to the basics. For the exhaust to be clean enough to pass the test, the engine must have:

1. Strong spark at the correct timing.
2. Engine with good compression.
3. Good air & fuel supply for correct A/F mixture (includes electronic engine control).
4. Properly working emissions control devices.

1. Plugs new, ignition wires new, caps & rotors new, ignition coil's good, so the spark is probably ok.

2. This requires testing with a compression gauge.

3. This seems suspicious. Is air filter new and is of Mann/Volvo? Is fuel filter Bosch? There might also be some deposits in the combustion chamber (most likely carbon sludge) that is keeping the combustion temp high. Or could be clogged/dirty injectors.

4. Another suspicious system. Is PCV system in good working order? EGR's out of question, you've described enough about it. Is there any leak in the exhaust system, before the CAT? Is the O2 sensor (s) Bosch?

Lastly, what brand of oil are you using? Switching the brand of oil might play a trick, though probably not by much.

If all of the above is good, your last resort is to visit a Volvo dealer and have them do a thorough testing.

I'm sorry I couldn't help you any better.


JPN

 

thanks for the help JPN, any little bit helps.

First off the combustion camber is clean, when I had the intake off the valves and intake ports were flawless, not a spec of carbon and the piston tops from what I can see are clean as well.

The PCV valve, i know that I do not have a PCV valve in the stock location which seems to be off that black catchcan container under the intake into the valve cover right beside the oil cap. It could be elsewhere and I will take a look to make sure. All my blackbox has is the one coming in from the block and one going out to the flame trap.

The air filter is Ok, its not that dirty, but if the airfilter was dirty that would reduce the air going into the engine which causes a rich mixture.

The O2 is the only item to consider, but its newer, no idea what brand it is.

its going back into for some emission's diagnostics on Tuesday unless I can figure something out over the weekend.

 

I have had some friends have amazing luck with running bottles of Techron Fuel System cleaner. They would start with about 1/4 tank of gas, put in 1 bottle and run it to near empty. Then do it that again. Techron might run you around $6-7 per bottle but it is good stuff. I would consider changing your fuel filter afterwards as well.

What was the most recent tests readings (with the limits). I almost wonder if the catalytic converter is bad. If you have no downstream o2 sensor, the only way to know would be an emissions test.

I feel bad that someone bastardized your car prior to you getting it. The fact that everything is not where it should be is a shame. - AB

 

I already ran a bottle of Redline Fuel System cleaner thru a half tank.

The NOX readings are as follows, 2048, 935, 2750, 2400ppm. the limit is 435. The HC and CO are clean.

The car is in great shape, its my soon to be father-in-laws old car, it has been dealer serviced by Volvo since new, he always ran premium gas too. And the fact that there is no egr and no PCV is not someone removing it, its just not there from the factory, there is no mount on the intake for an egr, nothing...this car is weird.

Also the cat converter is new as of 2 weeks ago.

 

Im in the same situation as you... Went in for a CA ASM smog test and passed with flying colors for Hydro Carbons, and CO, but nox was off the charts. Does this imply the combustion chamber temp is too high because there is too much air(plugs indicate very lean mixture)? If this is the case it must be something not monitored by the computer because the other numbers are correct(???). If all this is true, the only possibility is clogged injectors/not enough fuel pressure or an intake leak. Ofcourse the O2 sensor would pick this us. Hower I have a scanner I can plug in my 96 and monitor the values of the sensors, and the O2 is flucating quite rapidly from .005 or so to .9 volts. This would either indicate it is functioning properly or maybe it is compensating for something else, or im wrong. Maybe someone can chime in about further 02 sensor testing, and explain why it doesn't affect my other values. I am no genius, but quite a big car nut. I would much rather run a bottle of redline, then change out my fuel filter before replacing a 140 dollar sensor...

Thanks in advance,
Brian

 

bump!

 

Have you checked for vaccum leaks yet?
How old is the oil?
Is the vent system clogged?

 

Car has fresh oil, and I did a quick check for vaccumm leaks... Havn't yet looked at the flame trap, and the EGR valve. Is the only way to clean the EGR valve by removing the Throttle body?

 

Usually the best way to clean the EGR good would be to remove the Intake manifold.

This way is assures everything is cleaned good.

 

Any idea what fix was? I have a 93' 960 and just failed emissions this weekend. nox was at 2073 and has to be in the 880 range.