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Fuel Injector Problems

Arjun Kulkarni
Fuel injectors came into the automobile mass-production scene around 1980. It served its purpose as a more efficient option to carburetors. But, as with any complex mechanical unit, fuel injectors have a downside to them as well.
Mechanical fuel injectors were created and put to use by 1940s, mostly in racing cars. With the advent of the electronic fuel injectors in 1957, the automobile industry realized that although complex (at that time), they could use it to help suppress increasing fuel consumption and relax high fuel prices.
By 1970, the U.S.A. created new laws to restrict fuel emission levels, forcing a lot of car makers to either build a better carburetor or adopt the electronic fuel injector. They chose the latter, because creating better carburetors was more costly.
It goes without saying that a piece of mechanical equipment that handles the flow of petroleum-based fuels at high pressures on a daily basis is bound to get dirty, wear out or become faulty. It also possesses its own guidelines for maintenance, which is better left to professionals.
Fuel injector problems should be addressed with urgency; they are so vital and close to the engine that any problem with them will translate to engine problems in the future.

Common Problems With Fuel Injectors


Dirt is one of the biggest culprits that damage the fuel injector. The dirt can come from either low-quality fuel or rust inside the fuel tank. The dirt gets clogged inside the fuel injector, changing the fuel distribution patterns.
You'll start having troubles accelerating the vehicle, because the clogged dirt may not let the fuel to pass through the injector smooth enough. It could cause the injector to overheat.
If the rust travels into the engine, it could affect the pistons. A dirty injector may also result in a poor fuel economy, as in an effort to spray the fuel, it might end up spraying more than required.

Baking of Additives

The second biggest reason for injector problems are unburned additives. They usually collect on the injector's pintle and harden (get baked) because of overheating. Usually the fuel injector's temperature goes down smoothly when the vehicle is turned off.
In some cases (usually aging), the heatsink fails and the excess heat causes any fuel additives to saturate and harden. This happens on the same place where they get collected when the injector stops - the pintle. The pintle is the small opening valve that allows or stops the spraying of fuel from the injector to the engine.
So if the pintle gets jammed, it could seriously hamper fuel transmission. It can go both ways: it could jam the injector so it won't open up completely, reducing fuel output. Or it could prevent the pintle from shutting the nozzle completely, creating a loss of pressure inside the injector and leaking fuel into the engine.
If you have a leaky injector, that is probably because the injector pintle is not sitting on the orifice perfectly. This may cause difficulties in starting the car and in some cases may cause damage to the oxygen sensors.


Sometimes, it may happen that the external electrical connectors of the fuel injector may get corroded or may even break. It then results in either no firing, weak firing, or intermittent firing. It may again lead to poor engine performance and low mileage.

Pressure Release Failure

A badly maintained fuel injector could also have the problem of not being able to release its internal pressure.
The injector should be in a depressurized state when the engine is turned off, but there could be situations where the injector still remains pressurized. It is particularly hazardous trying to clean such an injector; it could cause the high-pressured fuel inside to burst out when the pintle is manually released.
Bad maintenance is one of the prime factors for problems in the fuel injector. Not maintaining other vehicle parts could also result in damage to the injector. The injector itself is a costly component, and its damage could easily get transferred to the engine as well. Which is why regular maintenance from a qualified mechanic is advised.