TuneUp Query

Hi, I live in Australia & have recently brought a 5/85 Volvo 240 GL, It runs beautifully on the road but has a bit of a miss/ sounds a bit rough at idle. I have changed the plugs and rotor. I was wondering, the car doesnt have a cat (it has upper cylinder lubricant), should this car have an o2 sensor even tho it doesnt have a cat? I cant seem to spot one. And can anyone recommend any service items I should check, I am going to pull the mass air flow meter off and clean it on the weekend and see what happens. Anyway this is my first volvo and I want to get it running as it should! thanks.

What fuel system is it? Carb? non lamda k-jet? lambda k-jet? or later type electronic fuel injection (Lh 2.2 or 2.4)? got any photos of it (and the engine bay)? Is most likely the non lambda (o2 sensor) k-jet type. (easily identified by the flat topped inlet manifold and large black rubber bellows on the K-jet unit. (under the inlet manifold) if it is kjet, it may be well worth changing the injector seals (2 per injector) they crumble after time and leak air into the head. Also carefully examine the engine loom (especially under the inlet manifold) as they wiring insulation goes bad and falls off causing dodgy running) If its the later type with fuel injection (you mention the air mass meter) which makes sense if its this type, dont clean the AMM as you may damage it, its only a very thin fragile wire that must remain clean (the air filter should take care of this) , any grease or dirt on it could destroy it.

Hey mate, It has the flat top inlet manifold & large rubber pointing downwards, The owner has replaced injector seals at 290,000km and its about 35,000 more then this now so maybe thats not the drama, also has new exhaust etc. I havent started pulling it apart, So obviously theres no sensor under that rubber, would there be much that might be making it run rough, as without the airflow meter and o2 sensor this engine must be pretty basic eg. mechanical injection. Sorry if I seem stupid I dont have an idea about volvo electronics but I am going to learn.

No probs. Ok so its K-jet, non 02 sensor type. First thing to do is make sure everything is spot on as far as servicing is concerned, there's no point trying to make it run well if it has bad plugs for instance. These cars like new plugs every year at least, and gap them to .7mm. Nothing fancy just regular plugs. I would also get new leads, rotor arm and dizzy cap. change the fuel filter and air filter. Set the timing to 12 degrees BTDC. Run it with good fuel, they are meant to be run on 98RON. Double check that all the (intake) hoses and vacuum pipes are connected and in good order. Generally you dont need to mess with the K-jet settings, as long as the system is in good order it should run well and messing with them can cause a nightmare tracing problems if the system is faulty.

Read this to understand more about K-jet, it is a good system that will keep running a long long time with no messing. Most running problems are not usually caused by the K-jet with this car. Preventative maintenance is the key.

Hey thanks for the link, I will have a good read of it. In the mean time I think checking the timing and cleaning/replacing the injectors & seals might be a good start. It seems to run just fine when going but I want to fix the big vibrations and rough idling as soon as I can.

rough idle! 

Hi there just another thought,When was the cambelt last changed? I once had one booked into a car clinic for a setup because although it ran smoothly it was all over the place when ticking over.I had tried just about everythink and decided to let the experts sort it.The engine used to rock from side to side it was that bad. I thought I may as well change the cambelt and let them adjust the timing so it would be spot on.Imagine my expression after refitting the new belt and then starting it and finding out it NOW idled smooth as ice,took the car to be setup and was told everything was spot on and didn't need any setting up. So I imagine the belt had stretched and caused the timing to be very slightly out.Best of luck Brian.

Hey, The belt was replaced about 50,000km ago, I called the old owner and he said it had been running this way for a fair while, so maybe the belt wasnt put on properly. They are about $20 trade here so will give it a try, will also clean the throttle body and replace any perished hoses I can. And give it a spray leak test and hopefully Im running good as gold again. Thanks for your help.