Good Morning, (sorry for the long post)

I have a 1990 240. Every two years it fails the emission test, so I buy a new Cat (bosal), it passes, and I drive on for two years until the next test. In the last 6 years, I've put on 3 cats...

My next test is coming up in 8 weeks, so I'm considering installing some new parts to address a few issues and hopefully extend the life of the new cat I will have to install.

Here's my plan:

1. replace the fuel pressure regulator (car will sometimes stumble in the morning for 10 min then fine)

2. replace the idle air control valve (often idles surges after putting the car in park after a highway drive)

3. clean throttle body and replace gasket (check intake hose for any leaks)

4. clean/replace flame trap if needed

5. I am also considering a new AMM. This is a part I have replaced with used models in the past. I have always hesitated to shell out for the new one, but am willing to do if it will help address the cat and other idling issues.

My thoughts are that installing all of these parts in conjunction with a new cat will smooth out the ride and keep the cat going a bit longer.

The plugs, Cap and Rotor, Spark Plug Cords, and speed sensor have all been replaced within the last two years. I replaced the Fuel Pressure regulator about 6 years ago but have never replaced the idle air control valve. In-tank pump, fuel filter, used AMM, air filter, check valve, O2 Sensor and fuel pump have all been replaced before.

I guess my questions are:

- will this help extend the life of the cat and smooth out idle issues?
- Is there anything else I should consider?
- Is it worth it considering I may only keep the car for another 2 years if it
lasts?

I don't mind spending some money to make these improvements and keep my 240 in good health, but also don't want to throw too much money at a car that may only last a little while longer.

Any help, thoughts, comments are appreciated and again, sorry for the long post.

Happy Friday!

First of all, thanks again to everyone who has contributed to this post. I am amazed at the collective depth of knowledge each of you has.

I thought I would post my CAT emissions numbers from over the years to see if anyone can make any connections. Maybe I can finally figure out my CAT killing engine

A bit more info. I am in Ontario Canada where we need to have emissions tests every two years for older vehicles. I have taken the car to various testing facilities so, unfortunately, no sneaky mechanics to pinpoint. I also buy the cat separately and have a muffler shop do the install, so again no garage is getting all the benefit of my CAT woes...

Here are the emissions limits for Ontario:

40km or ASM525 Curb Idle

HC ppm 62
CO % 0.35 200
NO ppm 700 1.0

As always, thanks in advance for any feedback. It is greatly appreciated.

2003-PASS 40 km/h Curb Idle

HC ppm 67 49
CO % 0.14 0.01
NO ppm 4



2005-FAIL 40 km/h Curb Idle

HC ppm 83 48
CO % 0.7 0.33
NO ppm 3007

2005-PASS 40 km/h Curb Idle

HC ppm 31 22
CO % 0.1 0.00
NO ppm 55




2007-FAIL 40 km/h Curb Idle

HC ppm 109 124
CO % 0.78 0.82
NO ppm 2620

2007-PASS 40 km/h Curb Idle

HC ppm 11 8
CO % 0.02 0.00
NO ppm 241




2009-FAIL ASM2525 Curb Idle

HC ppm 97 178
CO % 0.59 0.7
NO ppm 2491

2009-PASS ASM2525 Curb Idle

HC ppm 35 60
CO % 0.04 0.01
NO ppm 105




2011-FAIL ASM2525 Curb Idle

HC ppm 118 96
CO % 0.63 0.21
NO ppm 2321

2011-PASS ASM2525 Curb Idle

HC ppm 61 31
CO % 0.10 0.00
NO ppm 458

My summary:

Failing all three categories each time??? Emissions at idle always PASS, at 40km or ASM2525 (new emissions category) they fail. I replace the CAT, the numbers fall within range. In two years, by the next test, they all fail again???

Work done within this time period:

FPR replaced, Flame Trap replaced, Throttle Position Sensor replaced and cleaned, AMM replaced with used model, intake hose replaced, air filter replaced, plugs, cords, cap and rotor have been replaced, fuel filter, check valve, fuel pump, intake pump and sender unit, 02 sensor - all replaced.

Potential causes that haven't been repaired replaced:

ECU or IAC?

Any thoughts, connections, conclusions???

I'm late to this thread but thought you hit the nail on the head with the #1 thing you listed in your first post---stumble for first 10 minutes. To me that could indicate a bad engine temp sensor. That seems to be the one item you never addressed. -- Dave

I will add it to my list!

Thanks...

Only $21 from fcp too!

GJ

Forget purchasing the AMM, clean the IAC do not replace, Clean Throttle body(that's your idle surge), Check FPR for wetness on the front hose and make sure that hose is attached to the intake manifold.
Change the oil right before going to the emissions.

--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html http://cleanflametrap.com/tony/

Happy Saturday,

Checked the FPR. It was dry, but did smell a bit like gas. So, I will be replacing that... I'm gonna poke around a bit more and do some more research about the coolant temp sensor and its effects on high NOX and the engine temp sensor.

I've had each CAT installed at the same shop. I buy the part online and they just install it, so they don't make too much $$$ from me. I am wondering whether they put a gasket between the header pipe and the CAT. If not, could air enter the connection and kill the CAT?

Also, I never put in fuel additives.

Bricker

Don't replace the FPR just because it smells like gas. It's supposed to have some gas odor. If it's leaking that's a different story...

Agreed:
You should not be losing a cat every 2 years. That just sounds sort of insane to me.

You get only 20ish mpg? I get better than that in my turbo automatic.

DO replace/clean the flame trap. This needs to be a regular maintenance item.

Do you lose any coolant or anything? Do you add anything to your oil or fuel? Do you fuel up at the same spot consistently?

In CA, there's a "lifeline" thing you can do once in the life of a vehicle where you take it to a shop and they do smog-related diagnostics, and the state covers up to $500 of the repairs. But then you're taking it to a shop and paying labor out the wazoo. I did it. Cost me $80 or so to get a $200 sensor (92 EGR) from the dealer that way, but it worked out in the end.

I would suggest you measure your fuel pressure, if you can do that conveniently. I don't know if there's a way to do it, short of having a schrader valve built into the rail. Anybody else know?

I don't think the Idle air control valve (IAC) is involved.

One thing I would say might help would be replacing any plastic intake tubing. They do tear enough that it's a problem.
Another thing that might help is running seafoam & distilled water (look up the procedure, and don't hydrolock your car). NOx is caused by high combustion temps, which can include 1) lean mixture due to fuel problems or intake leaks 2) air leaking into the exhaust before the cat 3) a failed O2 sensor 4) carbon deposits on the piston that increase the compression ratio and therefore increase the temperature at ignition. I'm not sure of any other possible causes for it.

Good Luck!

have you ever replaced the intake manifold gasket? Those can leak and the leak will cause high NOX readings. Not too hard to do and not a lot of money.

Thanks to all posters... I appreciate all of your input. I'm going to examine my emissions files and post. Anniversary tonight so no time for 240 research - lol. Again, I appreciate all of your input and will begin problem solving.

A cat every inspection period?!!! Two very different questions to address two possibilities ... keeping in mind that your experience is very unusual. And usually the need for a new cat is easily indicated by a particular pattern of excessive emission gases. Do you have the information to report which gases were excessive?

In any case, your experience suggests (IMHO) two possibilities:

First, is your inspection done by a state-run inspection station that does not do any repairs? Or, is it merely a state-authorized inspection site operated by a private garage? [in my state, we have both, and can go to either type of inspection]. And who has done the repair (i.e., installing the new cat each time)?
I'm thinking that, possibly, you've been going to the same, unscrupulous test station (run by a private garage) who has just been taking your wallet to the cleaners every two years -- telling you that you need a new cat, and that "we'll do you a favor and save you time by replacing the cat here" or something like that.
If it's a private garage who can make repairs, I would take your car for an alternative inspection at an alternative test site to see if the first one has been accurate and honest.

Second, although it is very rare, something about your car might be poisoning the catalytic elements. A fuel tank additive that you may be using, or a incorrect fuel-air mixture (either due to a fuel injection system problem or else a leak in your intake passages), are possibilities, along with perhaps a really contaminated fuel supply at your favorite gas station.

In any case, you shouldn't have to be replacing the cat every two years!!!

Your 1990 Volvo 240 comes equipped with the OBD-1 diagnostics for the Bosch 2.4 LH fuel injection and the Bosch EZK (and EGR, if equipped, through the EZK) ignition systems control systems.

While not conclusive, you could use the OBD-1 as a start for fault diagnostic in seeking the cause or causes as to poor running and fuel economy that may lead to premature catalytic convertor failure.

As others have said, high NOx, can be caused by:
- Lean running condition (Air intake leak, spark plugs too hot, faulty coolant temp sensor, )
- Exhaust system leak ahead, usually high up at the manifold, of the catalytic convertor with weak or failed 02 sensor
- Overheated AMM (or MAF) as the air box temp control flap valve is stuck on hot air in only if you have the silver accordion hose connected to the exhaust preheater plate and the heated air intake on the air filter box.
- Faulty timing (I forget whether too advanced or to late)

It may be very possible you may have a rich running condition (excess fuel) and some conditions causing excessively hot combustion chamber or exhaust temperatures.

Please see (http://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm).

If not already, please acquire a blue Bentley Volvo 240 service manual.

Hope that helps.

Not Loggedin MacDuff
--
Fuzzy kitties.

Why exactly is it failing?

Also, are you getting the car good and hot before testing?

I will have to double check the report when I get home but I believe it usually exceeds the NOX category?

Thanks

If you can, post the NOX reading and whatever the limit is for whatever state your in. If you're only failing by a little bit, getting the car good and hot before testing might do the trick.

A while back I had an '84 that wouldn't pass unless I got it VERY hot before testing--like run it on the freeway at 75 mph in third gear for a while hot (that's on a stick shift, it yours is an automatic try 2nd gear). Anything less than VERY hot and it would fail NOX by a tiny little bit while everything else they tested for easily passed. Get the car VERY hot and it would pass the NOX test by a tiny bit instead. Might work for you. Seems crazy to have to replace a cat every two years.

Hot probably was not the reason, since nitrogen oxide is, I have read, formed in the combustion chamber at very high temperatures. It was probably more to do with the efficiency of your catalytic converter at higher temperatures (it does it's job better when hotter).

You could reduce NOX readings by finding a way to cool the engine more, while keeping the cat hot. Or drop combustion temps. I was told by a mechanic once that retarding the timing will cool the combustion temps, resulting in lower NOX. Increasing the fuel charge to run rich might also do it, but of course that would increase your HC reading.

I should have said that the engine being hot is not the reason for passing, but rather, the cat being hot. I think that's the real key to NOX - your engine fully warms up in minutes, but it may take quite a while for the catalytic converter to heat-soak to the point of maximum catalyzing efficiency.

I bet I could design a cat heater element and temp gauge. If I had access to emission testing equipment, it would be a fun experiment to see how the heat of the catalytic converter effected the emissions reading.

To the original poster, FWIW, my cars almost always scrape by for NOX on the 25mph test, but pass much better at the 15mph portion (here in VA). And I attribute it to the fact that the 25mph test is performed first, thus heating things up a bit.

Good Point!

May be the case with my 240 too... At idle speed, it always passes... 40km/h is where it fails...

I posted my "numbers" over the years at the bottom of this thread, if you're interested...

Thanks again

http://www.epa.gov/otaq/cert/factshts/catcvrts.pdf

The above URL states that any aftermarket catalytic converter must be warranted to meet EPA emission performance standards for 25,000 miles. It would be good to ensure that everything on your car related to fuel injection and ignition were working properly, as those things can shorten the life of a cat. If everything is operating within tolerances, then you should get at least 25,000 miles out of your cats. It may take some research and work, but you could probably get your cats replaced for free if they are not lasting that long.


I previously thought that the required warranty was 5 years or 50,000 miles, but reading the above document this time has made me realize that only the pipes and converter shell must last that long; that is completely ridiculous.

But it sounds like you're driving this car as a beater until you can buy something better. What makes you think it won't last much longer?

Thanks for the info scorron!

The car is actually in very good shape and has been well maintained (more or less).

I will likely keep it as long as I can. I am just always aware that, because of its age, something could happen to it that might not make sense economically to repair given its age and value (so to speak).

The re-occurring cat issue, which i assume is because its running too rich, is also kind of a pain... as is no A.C. lol.

Can you suggest things I should do or check for fuel injection and ignition that I haven't already listed?

Thanks again for the info!

Check/test the things you mentioned and replace as necessary.

The only thing that ever kills a 240, that makes it financially unfeasible to repair is serious rust. Everything else is cheap enough that with a little work and creativity - and shopping around, talking to the Volvo community, etc. - it will ALWAYS be cheaper to fix a 240 than to buy a new car. And remember that almost no used car in the world is trouble free, and people sell cars after they are tired of repairing things, or after the cars have been neglected so long that they need tons of work. It will ALWAYS be cheaper (in terms of money) to keep a 240 driving than to own almost any other car. You also have to consider the dirt cheap insurance and taxes on a car worth practically nothing.

What is your mileage like? That will be a clue as to how your car is running, and whether you are dumping unburned fuel into the cat.

The AC is a problem; I hear you. I spent several hundred dollars and a LOT of time getting my AC to work last year. It can be done, but ultimately, it is a luxury item, and not 100% necessary in transportation. Even if you spend $1000 dollars getting your AC to work well, it is cheaper than $300/month for a car payment, higher insurance, taxes, etc.

I would say a new car will cost at least $5000/year to own, and a newer used car is going to have the same problems as an old 240, but will probably be more costly and difficult to fix. It will never make financial sense to get rid of your 240. That doesn't mean there are not other reasons to get a different car, but money will never be one of them.

I was getting about 400 - 450 km a tank - I believe about 20 mpg. Unfortunately, the odometer broke (I have the replacement plastic wheel) but had trouble getting the cluster out, but I think I'm getting roughly the same based on the amount of fill-ups I need.

I agree with your case for a used 240 vs new or another used car. That's why I've had it for 10 years now. The car is in very good shape rust-wise, and I still love the 240 styling which is why I'm happy to spend some money on it to keep it going. While I sometimes think about a new ride, I also would rather put my $ in an appreciating asset rather than a depreciating one.

I basically use the car as my work commute vehicle - about 40km roundtrip, and use the wife's honda for anything further afield.

I've been through the trials and tribulations of the 240 over the years I've had it and enjoyed being able to learn more about cars, troubleshoot, and actually fix many things myself even though I'm not the most technically inclined - hence my question.

So, can I assume that you would recommend upgrading the things I mentioned - FPR, IAC, AMM? More as a preventative thing? I have no problems with the FPR and IAC. At about $325 for the Bosch AMM, I've always gone with used ones for about $50 ish, but always wonder whether they're 100%

Thanks again for the time and expertise in your responses!

GJ

So, can I assume that you would recommend upgrading the things I mentioned - FPR, IAC, AMM? More as a preventative thing?

Nope. Never as a preventative thing. One easy way to go broke on an old car and get angry fast is to replace parts that may be good - which are expensive parts - and hope it will improve something.

There are some simple tests you can do to determine if the AMM is sound. The IAC is a bit trickier, but you can still determine if it is doing it's job well without swapping it out (although that is easier). You can determine if the FPR is failed quite quickly, by pulling the vacuum hose and smelling for gas. To determine if it is actually providing the proper pressure might require gauges and creativity, but I think a BOSCH FPR is pretty expensive these days, so I wouldn't just replace it out of the hopes that it will help.

400 - 450 km a tank is no way to accurately measure mileage, but if you are getting 20mpg, then you're probably doing fine. My '93 has always gotten 20mpg around town, and has always smelled gassy - rich - but I have never failed an emission inspection for HC or CO, only NOX - which usually means it is NOT running rich.

You can also, BTW, probably get through emissions by adding some extra alcohol to reduce HC and CO readings, and retarding the timing to reduce cylinder temperatures, thus reducing NOX. But that's not a sure thing, and of course, isn't strictly especially legal. Certainly violates the spirit of the emissions inspection, if nothing else.

"So, can I assume that you would recommend upgrading the things I mentioned - FPR, IAC, AMM? More as a preventative thing?"

I would recommend getting these part and more from a junk yard, test them so you know they are good and keep them in the trunk for troubleshooting and repair on the road. Other parts to consider would be and ECU. powerstage, fuel and OD relays and the list can go one from there.

Dan