Hey Folks, My 1989 240 wagon failed the California smog test twice now, and I can't figure it out. I'm on the verge of taking it to a mechanic, but I'd like to see if anything jumps out at anybody.

I took it in once, and it failed, but just barely. I gave it new plugs, wires, a cap and rotor, a new crankshaft position sensor, a new (used) ECU, a new fuel trap kit, cleaned the oil trap AND the throttle body, and the numbers are WAY WORSE!

The car, incidentally is a 49-state car, and no EGR (pretty sure).

Late last month, my car failed the EVAP test, but I found and replaced a broken rubber hose leading to the rollover valve. My re-test a couple of days ago showed that it now passes EVAP. That's the good news.

The bad news is that my NO (PPM) numbers are way higher now. Last month, my NO (PPM) was:

NO(PPM)
15 mph - MAX:791 MEAS:0877 FAIL
25 mph - MAX:730 MEAS:0497 PASS

After the tune-up and replacement of the ECU and crankshaft position sensor, AND after driving at least 40-50 miles in all conditions (uphill, freeway, in-town) to let the ECU re-learn and warming the car up on the freeway, my retest showed:

NO(PPM)
15 mph - MAX:791 MEAS:1953 FAIL
25 mph - MAX:730 MEAS:1295 FAIL

SO, I barely failed before, but after a tune-up, new ECU, new crankshaft position sensor, new flame trap, clean oil trap and clean throttle body, the numbers are off the charts. (I did a bonehead thing and accidentally switched two plug wires at some point during my repairs and drove/limped the car around the block before discovering my mistake - does anyone think I could have ruined something because of this?) I've checked the internet and can't seem to find anything that applies to my situation.

I just went out and sprayed starting fluid around the throttle body and the the intake hoses with the motor running, and the engine didn't rev higher at all.

What's weird is the car runs great now. So much smoother and quieter than before. And my temperature gauge indicates cooler running temperatures than before.

My HC and CO didn't change significantly between tests. Here are the "before" numbers:

HC (PPM):
15 mph - MAX:116 MEAS:94 PASS
25 mph - MAX:91 MEAS:58 PASS

CO(%):
15 mph - MAX:.74 MEAS:.27 PASS
25 mph - MAX:.62 MEAS:.14 PASS

and the after numbers:

HC (PPM):
15 mph - MAX:116 MEAS:99 PASS
25 mph - MAX:91 MEAS:66 PASS

CO(%):
15 mph - MAX:.74 MEAS:.23 PASS
25 mph - MAX:.62 MEAS:.15 PASS

It's especially frustrating because I was so close to passing before, but now those NOx numbers are out of control. I might just bring it to the Volvo mechanic that I trust, but I know it'll cost me money I don't have. I really need the car for work, but if I don't get my smog, I only have until the end of this month until my final extension for my registration runs out.(Incidentally, CA has a program where the state will give you money to help pay for smog-passing repairs, but I don't qualify because I'm trying to register a car from another state. Guess it makes sense.)

Does anything jump out at anybody? Even if your suggestion is, "take it to your mechanic."
--
Wine Red 1989 240 Wagon

check the cat
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'92 240 208k totalled 4/14 - '91 240 192k miles

You have a 1989 Volvo 240. Either LH-Jet 2.4 or 3.1 and EZK ignition. You have OBD-1. You say you have no EGR. Use the OBD. See the FAQ for OBD articles.

Hi NOx (oxides of nitrogen) means (in no order):
- a too lean air to fuel ratio
- a small exhaust leak that lets air enter between exhaust outlet pulses
- or indeed, as silvermine instructs, a failed catalytic converter
- A failing MAF/AMM
- A failing or failed 02 sensor.
- Too hot a spark plug.

You may have some manner of corrosion at the wire harness connectors, including the ECU wire harness connectors. Use DeOxIt at these low DC voltage unions. Or you can use SuperLube silicon grease as it is dielectric at these connectors.

Exhaust leak as ... high up at the exhaust manifold or the exhaust manifold out to header pipe in (as gasket failure at this union, or the three nuts that secure this union closed are loose).

Also, on the air intake side, you can have vacuum leaks at any point after the air filter and into the air intake ports on the cylinder head (as a air intake manifold gasket leak - you may get buy with a one-time torque check of the intake port to cylinder head retaining hardware if the gasket is not entirely brittle, or you can risk fracturing the dried and in need or replacement anyway air intake port gasket). Inspect the entire system. This brickboard.com, including the FAQ, is replete with suggestions on diagnosing and resolving vacuum leaks. Fuel injector seals ....

Please start with the OBD-1 that seemingly no one ever suggests checking. Post the socket 2 and 6 fault codes here in a reply.

A Bentley, Volvo factory OEM green service manual (free-online), the Haynes (best is the dark grey 1997 final imprint) 240 service manual tells you how to do this.

Check OBD-1 at the black box. Socket 2 is Fuel Bosch LH-Jetronic 2.4/3.1 and socket 6 is the EZK ignition. The systems work in tandem.

Check the OBD-1 before replacing parts. While not wholly exact, and the nature of these systems is to compensate to the hilt.

See the FAQ, link above. See articles on OBD.

Do you have the silver preheat hose connected between the exhaust manifold heat shield and the air filter box? You need it there to pass CA-state visual inspection. Either clog the hose at the air filter box, replace the thermostat that controls preheated air to enter the air filter box, or use a bolt and nut combo to permanently close it. Easiest to seal it be stuffing the air inlet at the bottom of the air filter box. And you have a clean air filter, yes?

There you go. Hope that helps.

Reply with questions.

cheers,

Relocating MacDuff.
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Volvo 164: The Mightiest, most Powerful, most Beautiful Volvo Automobile Forever

Thank for the input! I somehow neglected to mention that the only code I'm getting from the OBD box is 2-3-2. "Fuel trim too lean or too rich at idle". According to the brickboard, lots of stuff can cause this, including the cat and the o2 sensor, as you gents suggest. I cleared the codes and took the car for a few long city and highway drives, with no codes appearing. After the second failed smog test, I recieved the 2-3-2.

Since I only have until the end of the month to get this resolved, I figure my options are these:

1. Keep searching for problems and/or replacing parts, them keep bringing it in to get smogged and paying for that until it hopefully works out. This could be expensive, time-consuming AND I might never figure out the problem.

2. Take it to a smog repair shop (where they have emissions-measuring machines), have them diagnose the problem, pay them for that, and then determine if I'm better off making the necessary repairs myself or letting them do it. This could be expensive too, but it seems like this option has a much more foolproof chance of resolving my car registration issue by the end of the month.

I've decided to go with option 2 for now. I've pretty much exceeded my skill level at this point. I couldn't find any vacuum leaks with starting fluid, and I don't have diagnostic tools to do any real testing. I try to do all the repairs I can, and the brickboard has been invaluable over the years, saving me literally thousands of dollars in labor. There's a good Volvo mechanic that I trust, and that's where I've brought my bricks when they've needed work I can't handle. He highly recommended a smog repair place, and I'm taking it there Monday for them to diagnose. If they determine that it's something relatively easy to fix (like the AMM), I'll do it myself, but if not, I'll leave it to them.

(What also sucks for me is that California will give people up to $500 bucks to make smog-related repairs, but I don't qualify because this is an out-of-state car being registered in CA for the first time.)

I finally and just barely started working (as a substitute teacher) after over a year of unemployment, and I desperately need my brick to pay the bills! I guess I'm just acknowledging that this thing has me beat, and even with all the great free advice that you fine folks have provided me with, I don't yet have what it takes to tackle this smog thing without paying some professionals.

I also want to be a good citizen and not a gross polluter. I remember back in the 70s when I was a little kid, how brown the air was, and how it hurt my lungs to breathe. Seriously. It's nothing like that anymore.

Thanks much for the input, and please don't judge me too harshly for wussing out.
--
Wine Red 1989 240 Wagon

The challenge you have in Cali is testing the result of your work. They've got you over a barrel if you're anywhere near as close to the deadline as you are. You can't analyze the gases yourself without a treadmill and sniffing equipment.

Two causes of the 232 stick out in my mind: holes in the exhaust system, and holes in the intake. The oft-given advice to squirt stuff around the manifold to find a vacuum leak is a relic of cars which did not have computerized engine management. It does not work like you are expecting. I would just replace the manifold gasket, if it has not been done; guaranteed it is crumbly by now if original.

Exhaust gaskets and downpipe holes are a bit easier to find with a stethoscope, but even so can elude. The problem you had earlier with the swapped plugs may have sooted up the O2 sensor, so you could put a new (universal) in, a new intake gasket and give it another spin on the dyno, but I know that costs money and it is just a gamble from the distant perspective I have.

But your option 2 should get things squared away if only you find an honest and skilled technician. She would probably smoke test your intake and exhaust instead of just telling you to get another cat and oxygen sensor.
--
Art Benstein near Baltimore

Flowers leave some of their fragrance in the hand that bestows them. -Ancient Chinese Proverb

Have you checked the fuel pressure regulator?

Yes, thanks. I unplugged the vacuum line and it was dry.
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Wine Red 1989 240 Wagon

I bet the problem is either a bad o2 sensor, or an air mass meter that is starting to "drift." In fact, my money is on the air mass meter. These can fail outright (your car will idle but fall on its face when you try to drive it), or they can fail gradually over time.

Last couple of times that I couldn't figure out why the car was running poorly (and after replacing the usual suspects), I installed a used air mass meter from the junkyard and the car ran perfectly again. I don't know where you are in California, but there are junkyards in the Bay Area that sell used AMM's with a warranty (60 days) for $75.

On all cars that are NOT equipped with EGR, the ONLY part that reduces Nox is the catalytic converter.

That being said, I to this day have issues with the way the test is performed.

It is ridiculous to expect the catalytic converter to work properly at low rpms unless it is pre-conditioned, which according to the smog check operators is not allowed and if caught they could be penalized a substantial sum.

Pre-conditioning is simply getting the catalytic converter hot enough to do its job properly which can be done by holding the rpms above 2000 for about a minute before performing the test.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Just wondering. Please advise.

Thanks,

Sat-Your-Day Packed Up Duffed.
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Volvo 164: The Mightiest, most Powerful, most Beautiful Volvo Automobile Forever

Thanks, Art. I was worried about my switched plug job having done some damage.

I'll report back here with results after consulting the highly-recommended professional. I'll bet you're right on the money.
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Wine Red 1989 240 Wagon