Common Causes of Gas and Diesel Engine Misfires

What are some possible causes for engines misfiring and how do you go about fixing it?

Engine misfires are a common occurrence with engines but the good news is that they are typically an easy issue to diagnosis.

Automotive misfires are a whole different animal than with diesel engines. Diesel engines ignite the fuel through compression where as automotive gas engines use a spark from an ignition system. With automotive misfires an ignition system is the first place to start looking for the misfire. The next appropriate steps to diagnose the problem include inspection of the ignition cables, spark plugs, distributor cap/rotor components and the ignition coil. The spark generated for ignition oftentimes will not be properly transferred as those components mentioned above wear significantly over time. The inability to ignite the air/fuel mixture in the combustion chambers will result in the engine not being able to turn over.

If you encounter a diesel engine misfire follow these steps:

1. Firstly make sure you are using a quality diesel fuel. Inspect the diesel fuel to verify the source has no contaminants; including water, dirt or oil.

2. Check the fuel system service log. Replace the fuel filters as needed and drain water from the system using a fuel water separator.

3. Once you've made sure the engine is up to service and the fuel filters are replaced inspect for broken or leakage in the high pressure fuel lines. You can pressure test the fuel line however most leaks are exposed and are easy to get to.

4. Fourthly, check for low fuel supply pressure.

5. Fifthly, check for bends or kinks in the fuel line and transfer pump.

6. Check for clogged suction pipe (in fuel tank) or plugged suction hole.

7. Check for air in the fuel system and check fuel pressure.

8. If pressure is lower than specified replace the fuel filters.

9. Inspect the return valve for free moving poppet, if low replace the transfer pump.

10. If all of the above fail to diagnose the issue there are 4 additional potential causes of the misfire:

- Improper valve lash adjustment
- Worn Camshaft Lobe
- Valves not seating properly
- Defective fuel injection nozzles or unit pump

The good news is that engine misfires are a common occurrence and not a symptom of something more serious that is wrong with the diesel engine. Each engine is different and for example John Deere engines have a thicker gauge fuel line than say a Detroit Series 60 or a CAT 3406E. On a Mack engine the problem could be more with the injectors than the fuel line. It is important to check each engine component separately to rule out issues one by one and follow OEM specifications. Start with the easiest fix and work your way up. If you still have engine misfires it is best to contact a diesel mechanic for further assistance.

Capital Reman Exchange is a large diesel engine and diesel engine parts remanufacturing facility specializing in camshafts, crankshafts, cylinder heads, blocks, follower assemblies and full engine rebuilds. 

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What Is the Difference Between a Sports Car and a Roadster?

Have you ever looked at a car and thought maybe that could be a sports car because it only has two seats? It's elegant like a sports car and as agile as a sports car, but there is a difference between the two. Here is the difference between the roadster and the sports car.

The first car that was made is considered a roadster as it only has two seats installed and no roof. They also call convertible cars roadsters because of the convertible roof. Examples would include the Porsche Boxster and the Aston Martin V8 Vantage Roadster.

A roadster is often considered a sports car as it was made to emphasise the comfort and the handling of the vehicle. However, this was considered a sports car when the fastest car only had two to four cylinders and not a lot of horsepower. A roadster, now, can be just as fast as the BMW M3 but it's not as warm in the winter months though.

Sports cars are defined by the type of engine they have. The engine usually has to consist of eight cylinders or more to be considered a sports car or super car. Obviously the suspension and turbochargers are part of it but it's mainly how many cylinders it contains. The car should be able to go from a stationary position to one hundred kilometres per hour in just a couple of seconds; nothing a roadster can't handle.

Sports cars nowadays are front-engine and front wheel drive vehicles. There are few manufacturers who have rear-engines and rear wheel drive ability such as Porsche and the Audi R8. The layout has been changed because the performance of giving the car torque from the front is better and faster without requiring as much force to push the car.

Unlike the roadster, engineers and manufacturers have tried to make the sports car more practical in case a child or luggage was to be involved with the traveling. They call the four seating layout "2+2", which means that there the two occasional seats with the general driver and shotgun seats.

Both cars require specific types of wheels and tyres to ensure their optimum driving force. So the wheel suppliers take this into account when designing the vehicles. The wheels must be able to handle high speeds and tight corners.

These types of cars are so similar yet so different especially to the hard-core vehicle enthusiasts. Yet to a normal person, both could serve the same purposes just as well. One could be your holiday car for those hot days and the other could be your super elegant and fast family car.

A1 Wheel and Tyre is a private family owned and operated company specialising in the warehouse and distribution of wheels and tyres to the automotive fitment trade. The company has a well established operation in Johannesburg, South Africa.

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