CLOGGED FUEL INJECTOR SYMPTOMS
The importance of cleaning clogged fuel injectors cannot be overstated. But how to tell if your fuel injectors are clogged? Or faulty?
Engine trouble is rarely easily identified, but there are symptoms for every issue, symptoms that everyone can learn to notice.
So, in this article, I’ll try my best to help you understand how the various issues caused by dirty injectors present themselves and how you can learn to notice them in a timely manner.
Dirty, clogged, blocked, leaking or generally faulty fuel injectors have the following symptoms:
- Engine stutter, hesitation, stumbling – without the proper air/fuel mixture, the combustion inside the cylinders is impeded.
- Engine misfire – poor air/fuel mixture in the cylinders can cause an incomplete combustion event. The cylinder can miss a stroke, causing immediate engine power loss and a noticeable sound effect. When this becomes severe enough, the driver will feel a jerking action from the engine and/or powertrain.
- Performance loss – the engine needs sufficient fuel for a proper, strong combustion. If combustion is impeded, engine power suffers.
- Rough idling/engine stalling – uneven supply of fuel during idling can cause RPM to fall too low and result in stalling.
For example have a listen to this bad fuel injector sound:
In addition to performance issues, you will also have to deal with:
- Failing emission tests – the drop in fuel combustion efficiency causes incomplete or uneven fuel burn, increasing emissions.
- Increased Fuel consumption – when fuel combustion efficiency is negatively affected, you will often need to burn more fuel to achieve the desired levels of performance.
Blocked diesel injector symptoms are similar. And in many cases can lead to an easier diagnosis of the issue, as the lack of spark plugs in diesel engines mean that there’s one less potential cause for the problems.
When you notice any of these clogged fuel injector symptoms with any of your vehicles or other mechanical equipment using fuel injected engines, it’s definitely a good idea to look into some injector cleaning products.
However, once again it pays to emphasize the value of prevention. Proper maintenance schedule that includes regular use of injector cleaners (either liquid additives or manual cleaning kits) can go a long way in keeping your vehicles operating smoothly and reducing any repair bills down the road.
That’s because when it comes to fuel injector clogging, it is not a case of IF, it is a case of WHEN.
Meaning, that sooner or later the fuel injectors on your fuel injection engine will get dirty and will get clogged to some extent. This is especially true for machines that regularly operate for short periods of time (like driving short distances in the city, or using farm equipment) as multiple engine ignitions and shut offs will exacerbate the clogging.
It’s just one of those unavoidable things that comes with the territory of operating modern, fuel injected engines. Unless of-course you make sure to maintain your vehicle properly.
And while getting your injectors cleaned by a professional isn’t overly expensive (ranging from $50-100), having them changed because of irreparable damage can cost A LOT more. I don’t want to alarm you, but fuel injector replacement cost can reach well into the hundreds of dollars.
Though you can always choose to get your hands dirty and deal with the issues yourself, in which case check out this article: Fuel Injector cleaning – how to clean Fuel Injectors?
Why are fuel injector issues such as clogging or leaking so common?
Well, to put it simply – Fuel injectors have the important job of dispersing fuel into the engine at the exact angle and quantity needed for the engine to operate optimally. And because there are several fuel injector nozzles that must evenly disperse the fuel, it only takes one dirty nozzle to influence engine performance. So any risk to the injector is effectively multiplied by the number of injectors in the engine.
And despite the issues dirty injectors can cause, early symptoms aren’t always noticeable because modern engines have internal sensors and computers that can adjust the fuel mixture to compensate for minor errors. That in turn can cause the beginning phases of clogging or leaking to go unnoticed.
It is also worth mentioning that vehicles that use turbocharged engines are at a risk for uncontrolled, engine damaging detonations. This can happen due to an overly lean condition caused by the dirty injector.
Turbocharged engines that reach high RPM’s require a much more accurate fuel dispersion rate than other types of engines. If the fuel injectors are dirty of clogged or otherwise out of balance, the risk for engine damage can be very high.
It definitely makes sense to be proactive about this to save yourself a lot of money and headache in the long term. Fuel injector problems can be a serious matter.
This is not to say that detonation cannot become an issue on other automobiles as well, as it definitely can. However, for most regular fuel injected engines, detonation is more often caused by using low-octane gasoline. While liquid cleaners aren’t always designed for this, many products also act as fuel octane boosters, raising the octane rating of the gasoline and thus helping to reduce dangerous detonations.
Here’s a very good video that explains the entire concept of detonation and octane ratings in great, easy to understand detail:
At this point it is also fair to note, that all of the symptoms mentioned in this article can also refer non-injector related issues. Engines are complex pieces of machinery and there are usually several parts in the system that can produce similar symptoms when failing. So what you might take for a bad fuel injector sound, can at times refer to bad spark plugs for example.
If you want to be 100% certain what the issues are, a visit to a professional mechanic is always a good idea. However, the reason why I recommend fuel injector cleaners first, is because of their low cost and ease of use.
Adding some liquid cleaner to the fuel supply is a safe, time saving method to try before sending your car to the shop.
Let’s re-cap with this simple Infographic we’ve prepared for you:
So, next time you are driving your car, motorcycle, or operating any fuel injected piece of machinery, remember to keep an eye out for these symptoms that might indicate dirty, leaking or clogged fuel injectors. Or better yet, avoid them in the first place by using cleaners regularly!
And to see whether a cleaner has helped your car, try out our handy fuel consumption calculator! Check your mileage and keep track of how it changes.
– Jack
Jack can bad injectors cause a car to not start? I have done a lot of things to my car and cant get it to start I have put on a new fuel pump housing sending unit and fuel pump, and new fuel filter. Also new plugs and plug wires and new distributor cap and rotor button, and still it wont start it just cranks and cranks so could injectors cause this?
It might happen, but you’d probably see warning signs far in advance. Clogging tends to happen over time. The engine would have trouble starting and would stutter a lot when driving long before it would stop starting altogether.
Without knowing the full details about the car it’s hard to even start to diagnose. Better to take it to the shop and have them take a look.
Could be a crank/cam sensor. Either of those will cause a no start.
Had similar problem with my mpv in Ghana. Changed the dirty engine oil. N after two years have never reoccur
I kinda had this problem with my old pickup. It would turn over & over and sounded like the battery was weak. Checked plugs, wiring, distributor etc. Recharged the battery, tried charging devices & used a jumper vehicle & cables.
Come to find out it was a bad starter. Wasn’t putting out enough to get a good spark to distributor. Took to auto parts store to run a computer check on starter….it was bad….replaced & it fired right up (?) Good luck
I have a 2002 Lancer that won’t start, the guy I’m buying from he says it’s the fuel injectors that won’t let it start. How can I tell?
My kia sportage diesel sometimes difficult to start the engine when its hot,the engine idling slow after i start it then after few seconds the idling is ok. In the morning its easy to start,only when the engine is hot that i have difficulty to start it but sometimes ok to start it. When i cant start the engine,i have to force the key to start the engine,it can start. what is my car problem Jack?
Hi.
I have an 04 malibu. It has been messing up for almost a year. I have changed to spark plugs the coil pack and the icm. Ive been looking for what could cause this and started to look into the injectors. Do you this that the injectors my be clogged enough to cause a misfire code?
I have a 2001 Chevy Malibu with the same problem. Bringing up a code saying it’s misfiring on cylinder #3. Changed plugs wires coils and module and still the same code. Runs smooth over 2000 rpm according to the snap on scanner. Will tackle the injector removal next week when the parts arrive.
I have 95 Nissan maxima. Car dies while driving or gets a dead spot where engine is running but car isn’t moving, then suddenly surge forward. Can smell raw gas a times
My Commodore Does This To,It Will Run For 10 Minutes Then Cut Out/2 MinsLater Will Start Straight Up Then fail again unreliable scarey taking it out.Any Ideas Would Be Much Appretiated