I have a 1986 5 speed manual transmission turbo 740 Volvo. It has just failed the Emmisions test. I have changed the oil, oil filter, air filter, cap, rotor, and the plugs and wires look good. Is there anything else I can do to make it pass?... Many thanks Pete

how old is the catalytic converter??if it is original it probably needs to be replaced, my 89 just passed the (aparently acording to one reply) tough ontario emmisions test with flying colours (way under the limits). I had to replce the converter last january as it had cracked where the pipe goes in, but did nothing else except ask my dealer to make sure everything was attached and working, it was and it passed. if you have leaks in the exhaust (even if they aren't noticable by ear) this can affect the results as well.

hope this helps.

Many thanks... I hope it is not the converter as there is only 117K on the car.. and it is fairly expensive. But I am having a diagnostic test run on it.. ( $100 bucks just to find out where I need to spend money! LOL.. ) so I guess time will tell. many thanks.. Pete

Hi pete,

if it is the converter, don't buy a volvo one (I got mine from speedy, it works just fine) The reason I say this is because when my father had to replace his he was quoted $1300 (cnd) from (a very trusted) volvo dealership (they thought it was crazy too, maybe 16 valve specific?) his problem was solved when he was rear ended (car written off, replaced with an 850), but when mine went it was to speedy muffler and got it for $250 cnd, so big difference in price. Anyway hope you find your problem.

You might check your crankcase ventilation system - they plug up real quickly on the 740 turbo.My oil separator was completely coked up and it was amazing the difference after it was replaced. If your state emission test is anything like ours in Ontario then your 740 has a difficult job passing at the best of times. Check all the pipework and the flame trap - you will probably find them to be constricted and/or blocked.Its imperative that you have a slight vacuum in the crankcase at idle. Good luck !!

Peter 89 740 turbo wagon

Many thanks! although I don't know where the "flame trap".. is... or how to clean it... and is the oil seperator easy to clean ( let alone find.. where is it?.. )... I just bought this car and know next to nothing about turbo's or Volvos alone. If there is anything you can impart about my Volvo I would appreciate tremendously! :) Thanks again! Pete

Need more info what limits hwre you over and which were you okay on?

Bill D.

Hi Bill.. thanks for your interest in my problem. I have more info on my problem if you think it will help. the HC gpm limit is 3.76, I passed with a reading of 3.00. The CO gpm limit is 36.38, I passed with a 35.41. The one I failed was the NO 2 gpm the limit is 5.77, I failed at 6.25. (less than 1/2 gram per million). If there is any other information I can give you please let me know. And thanks again for your interest. Pete

Your reading are all high. I had the same problem unitil I replaced the cat. Now all the readings are extremely low. Only a cat will lower you NO. I got a direct fit cat from Louisiana Muffer Mart www.lamuffler.com 1-800-834-2635 for $115 . It fita perfect and works great.

Check out this site: www.howstuffworks.com There is a current feature article on Catalytic converters and how they work. At the end of the article there are a couple of links to sites with additional information. You can find all sorts of interesting things on this site.

I was reading a book published by Bosch the other day. It had some good information on emissions. I agree that all your readings sound high, but as I remember NO2 emissions increase with a lean fuel mixture and hydrocarbons increased with rich fuel mixture.

Good luck and post solution so we can all learn.

Nox or nitrates of oxide is related to the egr system im not sure if your car has an egr but im sure spending 100$ with an ase certified tech will be money well spent dont guess as replacing your converter may not be nesseary