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Followup To
Question -
Hey Jason,
glad to read about your experience....I most definitely need your help. I also own a 1980 240, B21 engine if I'm right. My father bought this brand new, and just gave it to me as a birthday present. As a matter of fact, this is the 4th Volvo I own...all 1985 and older!
Ok, this baby looks very good, but she's giving me a headache on a daily basis. Whenever I start her, I always wait to have the temp gauge move a bit...I mean she's old! For the first 15-20 minutes that I roll with her, she sounds really weird...and feels really weird at low RPM (less then 3000rpm). It feels like she's 'coughing'? Really feels like there's too much gas for the air intake? I mean, I might be completely wrong...it's just the way it feels. Carb issue? Fuel pump? Fuel filter? Would a good check up, replacing plugs, rotor, wire, ect help? May I mention that she also smells gas....fresh gas as a matter of fact...not burnt. THen, when I've been going around town for 25-30 minutes or more, she feels perfect...
Anyways, I'd really love to take care of this, as everything else is good on this car...
Feel free to ask me questions to help you figure it out..
Thanks for your time...and Volvo rules!!!
Dave
Answer -
From the sound of it, you are probably running a rich mixture. I'll assume this is an American bought car, meaning you have the B21F fuel injected engine. Usually when you are running rich, there are two possibilities. First, when was the last time you replaced the oxygen sensor? It is the thing screwed into the exaust manifold, and they were designed to be replaced every 30K miles. When they start to get old, they don't work well when cold. The oxygen sensor feeds a voltage to the ECU unit, which in turn controls the frequency valve of the injection system and adjusts the fuel/air mixture accordingly. Meaning, if the oxygen senser is old and "sluggish", it won't give proper exaust data, and your mixture usually goes way rich. If you can't remember when the sensor was replaced last, just buy a new one, they are only about $30. Also, check to make sure your frequency valve is actually functioning (again, that is the device that controls air/fuel mixture). You should be able to put your ear down close to the front of the injection manifold and hear a distinct buzzing sound when the engine is running. If you don't your frequency valve is bad, and again needs to be replaced in order to get your mixture back to normal. Finally, if this happens to not be a fuel mixture issue, I would check timing. I know that in the past, if I've had my timing too far retarded, I can get the same coughing issues with the engine at low RPM's. Yours should be right at 8 degrees. Let me know how it goes!
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Hi Jason,
thanks for your incredible...fast rsponse...but do I ever feel bad right now. I forgot to mention that in fact, that car was bought in Canada, meaning that it's a B21, Carburator....are all of those suggestion still valid? Thanks again...hope you can help me just the same. I'll be leaving feedback right away...
Dave
AnswerUnfortunetly you've stepped into a realm that I'm less familiar with. Apart from the fact that Canadian models were carburated instead of fuel injected, I don't believe they had the more complicated oxygen sensor/ECU setup that I described earlyer. Furthermore, they definetly did not have a frequency valve. I guess the only part of my advice that can stand would be to check the timing, but I would double check what degree a carburated version should be at (might not be 8). Beyond that, I would suggest you clean your throttle body, because sometimes gunk can get inside the injection chamber and foul up either fuel or air flows. And speaking of air flow, if your carburator operates on a more fixed ratio like I suspect it might, I would check for airflow stoppage somewhere, like the intake hose or the air filter. Reduced airflow would automatically increase the fuel/air ratio and could cause it to run rich.
To get more specific expert help with your carburated version, I will suggest two things. First off, go out and buy a Hayne's Shop manual for your car. I have one for mine, and it has been invaluable over the years. It will give you a complete breakdown of your carburation and things you can do to clean and troubleshoot the system. Also, if you want to ask a specific question, I would recommend the website www.brickboard.com. It is a free forum where Volvo owners can post questions for free and members of the community can answer. Again, I've gotten great help from those guys in the past, and you might even see my name once in a while on the answer sections!
Hope that helps, good luck with the troubleshooting!
