Issue with firing

Hello! My car doesn't seem to be able to fire properly, i've just changed the rotor and distributor cap, and the sparkplugs, it seemed to run a lot better after i did so, the light which shows that it burns unclean also disapeared, but the problems returned (within a day) and it doesn't run on idle mostly, but sometimes it runs just fine (although still the light which indicates it burns unclean still is there) and sometimes it idles badly, but it doesn't die, sometimes it just dies instantly after driven then coming to a stop, other times it just vibrates and seem to be fighti
Experienced mechanics share their insights in answering this question :
Misfires can occur from fuel supply, spark, and camshaft timing problems. You have replaced most of the ignition components that supply spark to your cylinders, but you could still need spark plug wires. They may look good and not be. Also, disturbing them by replacing the cap and spark plugs can make them work for a short time then fail as they did before.

What need to happen to figure out why your car is running bad is some diagnosis. This will require checking fuel pressure and doing a cylinder balance test. The cylinder balance test can be done in a myriad of ways. In your case, I would use a test light to short out one cylinder at a time. The car should run significantly worse when a cylinder is short out. If the idle of the motor changes very little when a particular cylinder is shorted, this cylinder would be suspect to having problems.

As stated in the first paragraph, it could be a bad injector (fuel supply), poor connection of the injector connector, bad spark plug wire or even a compression issue. The main thing that needs to happen here is some definitive diagnosis before any more parts are replaced. If you should need some help with this, a certified mechanic from YourMechanic can come to your location to perform a misfiring diagnostic.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

The most common reasons a Volvo 240 won`t start are a dead battery, an alternator problem, or failed starter.
In order to fire correctly, the gap between the two electrodes on the new spark plug must be properly set. Use a gap tool to adjust the side electrode (the one that hovers over the center electrode) until the gap is between 0.028″ and 0.032″.
Most four-stroke straight-five engines use a firing order of 1-2-4-5-3. This firing order results in the minimal primary (crank speed) rocking couple, and is used by the Volvo Modular engine, VW/Audi straight-five engine, General Motors Atlas engine and Honda G engine.
Faulty spark plugs or spark plug wires can cause your engine to misfire, reducing fuel economy, performance, and even prevent it from running altogether. Faulty Oxygen Sensor: Due to long exposure to hot exhaust gas, your oxygen sensor might need replacing.
If no spark appears, check for broken wires, shorts, grounds or a defective stop switch. Once you have confirmed that the stop switch is working, reconnect the spark plug lead.
Why Is The Spark Plug Gap Important? The spark plug gap influences the heat range of the spark produced to ignite the air fuel mixture in the combustion chamber. This makes it critical to engine performance.
Firing order affects the vibration, sound and evenness of power output from the engine and heavily influences crankshaft design.
Globally, the Volvo 240 is far from a rare vehicle. There were over 2.8 million models built using the 240 designation over its entire run, with a further 177,000 nearly-identical 260s produced during the same period.
All models still came with a 114-horsepower, 2.3-liter 4-cylinder engine, and either a 5-speed manual or 4-speed automatic transmission.
The most common causes of misfires are worn, improperly installed, and mishandled spark plugs, malfunctioning ignition coils, carbon tracking, faulty spark plug wires and vacuum leaks.
Engine misfires happen when one of the cylinders does not produce sufficient spark or compression and lack of fuel. It could involve more than one cylinder. It can be caused by a faulty spark plug, fuel injector, ignition coil and or worn cylinder.
At its core, an engine misfire occurs when the combustion reaction doesn`t work correctly, and your cylinder remains unfired. Misfires can occur both upon engine startup and even in the middle of engine idling. When a misfire happens, your engine might momentarily stumble, and it may even lose speed (RPMs).
The relationship between crank and cam timing events can also cause no spark, especially on Chrysler products. On these vehicles, the PCM won`t trigger the ignition coil if the cam and crank are out-of-sync.
The Spark-Plug Gap

However, if the spark plug gap is too large, the spark is unlikely to consistently “jump” across the long distance between electrodes, thus leading to a rough-running engine or one that doesn`t run at all.

Many think the larger the gap, the better. However, if the gap is too large, and the ignition system can`t provide the voltage needed to spark across the gap, or turbulence in the combustion chamber blows out the spark, misfires will occur.
Gapping fine-wire spark plugs

While most NGK spark plugs are pre-gapped, there are occasions when the gap requires adjustment. Care must be taken to avoid bending or breaking off the fine-wire electrodes. NGK recommends a round wire-style or pin gauge gap tool to measure the gap.

A smaller gap will yield a short, intense spark and will usually make the engine real responsive. A wide gap creates a longer spark arc but without sufficient “juice” from your ignition system, (including amps), it can be weak and yellow in color.
These plugs are pre-gapped at . 044″.
If the car cranks when you turn the key, but the engine won`t start, it could be because fuel isn`t getting to the engine. One potential reason for this could be dirty fuel injectors. Over time, the fuel injector nozzles can become clogged with rust, corrosion or debris.
When your engine cranks but won`t start or run, it could mean your engine is having trouble producing a spark, getting fuel, or creating compression. The most common causes are problems in the ignition (for example, a bad ignition coil) or fuel system (for example, a clogged fuel filter).
Flat, faulty or dead battery

The battery is usually the main reason that your car won`t start, and is one of the most common callouts to the AA. There are a few ways your battery might go flat or even die: Something electrical was left on in the car, like the lights, which ran the battery down.

Flat, faulty or dead battery

The battery is usually the main reason that your car won`t start, and is one of the most common callouts to the AA. There are a few ways your battery might go flat or even die: Something electrical was left on in the car, like the lights, which ran the battery down.

If your Volvo won`t start, but the lights come on, the battery is often the problem. A flat or weak battery is one of the most common problems preventing a Volvo from starting. Watch the dashboard lights as you turn the key to confirm that the problem lies within the battery.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Code p0010 camshaft actuator comes up, and mis fires. Just replaced intake manifold and these weren’t issues before that.
ANSWER : Hi there. There are a few possibilities here. It is possible that you had a valve timing issue prior to working on the manifold. These engines have a ton of issues with the balance shaft and the valve timing as the chain wear. It is also possible that there are issues with the work that you did. I have seen with these manifolds, severe warping and cracking which will cause this to occur. I would start by checking the manifold for vacuum leaks. If there are none then next the wiring needs to be checked for any pinched wires. If that is all fine then I would install a scan tool to check the camshaft and crankshaft sensor readings. If they are off then the valve timing needs to be checked.

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Car jerks when accelerating in reverse & makes grinding noise. Is this a transmission or computer issue?
ANSWER : Hi there. Typically when you hear a grinding noise when you move forward or in reverse it’s usually an indication of a gear fault either in the transmission or another driveline component. If this occurs only when in reverse, it’s likely a damaged reverse gear. It is also possible that it’s a hydraulic fluid issue not supplying enough lubrication or pressure inside the lines to fully open the gear. I would recommend having a professional mechanic come to your location and complete a car is hard to shift inspection, so they can diagnose the source of your issue and recommend repairs that should resolve this problem.

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ALTERNATOR ISSUE?
ANSWER : The voltage put out by the alternator is typically in the range of 14.2 V to 14.5 V as measured right across the battery posts. If the charging voltage is outside that range, then there is a problem with the charging circuit. The charging circuit includes the wiring, alternator, voltage regulator (often integral with the alternator), fuse link, and all terminal connections. So long as no fault is found in the wiring, fuse link and terminal connections, as measured using standard voltage drop testing, then typically the alternator would be condemned and replaced. Preferred replacement sources for the alternator are dealer OEM new, re-built dealer OEM, and aftermarket reputable name brand vendors such as AC Delco, Bosch, and so forth which may carry both new and rebuilt lines. New alternators are of course the preferred choice. If you desire that the charging system on the car be diagnosed for confirmation that you need a new alternator the recommended service is a charging diagnostic. Please let us know if you have additional questions.

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I get fire to my distributor coil. But I do not fire any of my plugs. My distributor won’t turn.
ANSWER : As you may know, the distributor has a small gear on the bottom end of it that turns with the flywheel as the motor turns over. If the motor turns over and the distributor does not turn, this would suggest that the distributor is either not installed correctly or that the distributor is broken internally and not causing the gear to turn with the flywheel. I would recommend having an expert from YourMechanic come to your location to take a look at the situation and replace the distributor if necessary.

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Issue with firing – 1991 Volvo 240
ANSWER : Misfires can occur from fuel supply, spark, and camshaft timing problems. You have replaced most of the ignition components that supply spark to your cylinders, but you could still need spark plug wires. They may look good and not be. Also, disturbing them by replacing the cap and spark plugs can make them work for a short time then fail as they did before.

What need to happen to figure out why your car is running bad is some diagnosis. This will require checking fuel pressure and doing a cylinder balance test. The cylinder balance test can be done in a myriad of ways. In your case, I would use a test light to short out one cylinder at a time. The car should run significantly worse when a cylinder is short out. If the idle of the motor changes very little when a particular cylinder is shorted, this cylinder would be suspect to having problems.

As stated in the first paragraph, it could be a bad injector (fuel supply), poor connection of the injector connector, bad spark plug wire or even a compression issue. The main thing that needs to happen here is some definitive diagnosis before any more parts are replaced. If you should need some help with this, a certified mechanic from YourMechanic can come to your location to perform a misfiring diagnostic.

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What is wrong with my car?
ANSWER : If the vehicle is not starting, simply request a no start diagnostic and the responding certified mechanic will get the underlying fault identified and resolved. Basically, the first thing to do is load test the battery. Although I understand your suspicion that the immobilizer may be preventing the car from starting, until an actual diagnostic is performed that is a speculative cause. If the immobilizer system is on, you may see a security warning light. If you see such a light, to temporarily override the immobilizer system, see these instructions. If you do not see a warning light, again I would not assume that the immobilizer is the problem because there are lots of other potential causes for the no start you are describing.

With a fully charged battery and the immobilizer system off, if the starter motor does not operate, either there is no power to the starter motor, hence the starter circuit would have to be diagnosed, or the starter itself is bad and it would be replaced. If there is no starter motor operation at all, that is if there is no starter operation with the key held in the "start" position, the procedure is to test for power and voltage drops to the starter motor/solenoid. If there is no power or a large voltage drop is measured, then the electrical circuit supplying the motor has a fault. That circuit begins at the battery and includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch, neutral start switch, and terminations. Basically, with a fully charged battery, and with the key held in the "start" position, the starter is either getting power or it isn’t. With the key in the "start" position, if the starter motor is getting power but the starter doesn’t work, then the starter is condemned and replaced. Note that starters can and sometimes do develop intermittent faults due to bad spots on the armature. The bottom line is if there is battery voltage to the starter (and no excessive voltage drop) and yet the starter doesn’t work, it’s dead. If you desire that a certified mechanic resolve this, please request a no start diagnostic and the responding certified mechanic will get the problem diagnosed and repaired for you. Please let us know if you have further concerns or questions as we are always here to help you.

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How do I tell the difference between an alternator issue and a starter issue?
ANSWER : If the starter motor is turning the engine over at adequate RPM, then you definitely do not have a starter motor issue. Even if you had a bad alternator (and the alternator should absolutely be tested, certainly when you install a new battery because you want to be sure the charging function is working properly) that would not prevent the car from starting. So, if the starter is turning the engine over, but the motor won’t run, you have either a fault in the fuel or ignition systems, or the air induction system. To "quickly" determine if it is a fuel system problem, you can try introducing starter fluid into the intake while cranking and if the vehicle starts at that point that would be an indication that you have, at least, inadequate fuel delivery perhaps due to a fuel pump issue. The most efficient approach to getting this resolved is to just simply request a no start diagnostic and the responding certified mechanic will make quick work of this for you. At the conclusion of the diagnostic he will let you know of the fault and the cost to repair. Please let us know how we can best assist you to get your vehicle running properly.

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does a leaking fuel pump and or an overheating coolant pump cause significant damage to the enginge?
ANSWER : It’s fairly unlikely that either recall had any effect on the piston rings. That however is not something I’ve seen very often, especially on an engine as "young" as yours. The fuel pump leaking is more likely to cause a fire if the fuel hits something hot or electrical. If the vehicle is an Audi dealer being checked and not an independent repair facility, calling Audi Customer Service might be worth a try. The engine is passed the warranty expiration but with broken piston rings at only 82,000 miles, it might be worth a try. If the vehicle is not modified and have maintained it in accordance to Audi’s recommendations, MAYBE they would have offered some assistance as sort of a goodwill gesture.

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