Granted, mines almost 1/2 million miles strong, but the last time I was in for my inspection, the technician put the probe up the tailpipe and because of the age of that metal, where the tailpipe turned, the probe went straight...out of the tailpipe and no one noticed, except me.

He played with the machine a bit before going back to inspect. I thought I'd pass for sure!

I guess he figured out there must be an issue when this old boy showed Zero emissions.

I know some say to over inflate your rear tires if you are close to passing. It fools the machine into thinking it's running at a different speed then actual with less friction.

Shhhh...don't tell them I told you that!

 

Thanks, the MAF was entirely replaced with no improvement (so, returned). Regarding a leak UPSTREAM of the O2 sensor, that I can't say. I'm not sure just where it is. However, the guy who installed the cat found an exhaust leak exactly like the one shown on Brickboard, crack about 6 inches long, and welded it shut. No improvement.

Test place told me yesterday that two (maybe three) other old 80-s vintage Volvos are now failing badly, just like mine. He suspects the CARB has changed the parameters of the rollers.

Now, I would not advocate this, but I have heard that running on a 50-50 mix of premium gas and methanol would cool things down and lower the NOX.

 

while these LH2.2 'california' 240's aren't as clean as, say, a modern Toyota PZEV rated car (wtf is partial zero?!?), in proper tune, with everything intact, they are quite clean. our nearly 1/2 million mile 87 240 started to get harder to pass smog, had to be run really hot the last few times before the test, and finally our mechanic said, "put a new cat on it next time", so we did, used the Magnaflow cal-rated cat, had a local 1-man muffler shop do the install, and voila, its now as clean as it was new...

 

As far as leaks upstream, I had to replace my downpipe on both of my 240s. I also have had to replace the exhaust manifold gaskets as they had developed leaks. The ones in the engine compartment are the hardest to find as it is hard to hear them due to engine noise and it is hard to feel them due to the wind from the fan. Keep searching as these are the most likely culprits for the high nox readings.

 

After mine got through inspection last year, my guy said the same thing. A new Cat is in order for the next inspection. In the past, the smog guys would shake their heads when reading the mileage, then reading the excellent smog test results and couldn't believe it. Sometimes, they'd come back and ask me if the mileage was correct, just to be sure. Not anymore.

My 740 used to be tested every 2 years, now they've gone to every year.

January is coming soon.

 

Already tried two diiferent new cats - Walker - so unless for some reason Magnaflow is enormously better, that is not my problem.. When the muffler guy found and fixed the exhaust leak, he checked all around with some little stethoscope-listening-tube-earphones apparatus, around the exhaust manifold flange (which was ALSO loose and he tightened it all up) so if there was anything downstream of the manifold I hope he would have heard it. Car even runs quieter now with those leaks plugged. I think the exhaust pipe was really loose on the manifold, he had many turns to tighten it. But, that has all been done.

 

When he tightened the exhaust manifold did he use new gaskets?

 

No. He did "sniff" around with his sniffer to hear if it was still leaking.

 

To All The Posters About Not Passing Smog in CA and elsewhere:

I had a bunch of tune-up things done to my 940 GL 1992, and I passed everything on the Smog test in CA
except I was 8 points over NOX.

I went back to the mechanic, and he suggested running the car with some injector cleaner pre-emission fluid I got
from O'Reilly, and then I failed everything because I had a full tank of gas. Will the injector cleaner burn off as
I get the tank down? The car actually runs great. I just want to get it back to where it was when it passed everything before except the NOX and then pass the NOX part so we are good to go. Any suggestions?

 

an italian tuneup with Techron in teh gas tank would be my first suggestion... add a bottle of techron, fill gas tank, get out on highway, leave it in 3rd (eg, overdrive disabled) to keep the RPMs up, and drive it til the tank is nearly empty, hot and hard (like RPMs in the 4000-5000 RPM range for extended periods).

its possible your EGR is clogged, did the mechanic test that? disconnect the vacuum line to the EGR valve at the EGR control solenoid, with the engine idling, connect it to a mityvac and pull a little vacuum, the engine should almost immediately stumble and stall, release the vacuum, it should catch right back up to a proper idle. if it doesn't the EGR valve or pipe are likely clogged and will need to be roto-rootered out.


if the EGR is good, and the italian tuneup doesn't cut it, you likely need a new catalytic converter. I've typically needed to replace those around 300K miles on my various volvos.

 

Dear Pierce,
Thanks for the tip. I am printing your idea out and will try it and let you know.

 

In California if you fail the state will pay for" Up to:1200 dollars,and go to a star repair station& get it fixed free,your smog place should have told you what to do!

 

Fuel EVAP system probably needs attention.