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.
Great article. I have a 2007 Dodge Ram 1500 Hemi 5.7 L. Have been having all of the symptoms above and engine light has been on. Took it in for a diagnostic and found evap leak with code for LDP pump so changed that out. Then we got a code for Lean code – replaced Intake Manifold gasket. Still have the same symptoms as above. I know you mention it can be other things besides the fuel injectors so just curious what else it may be. I am noticing the issues when truck is at 30-50km speeds only. Higher speeds are fine. Many thanks.
Hi I have a 2006 vw Passat b6 2.0 Tdi sport I have a few issues with it first is when it’s running at idle it shakes really bad second is looses power sometimes and sometimes smokes when the dpf light is on. Need help
Sounds like your dpf is blocked – you need to run a ‘dpf regeneration’ to burn off all the carbon buildup. You may need to use a computer to do this.
I have a 97 nissan sentra 1.6. It is sluggush and poor throtle respond i can feel pull when i go but let go of gas and it jerks. Injectors never replaced or cleaned. Do u recomend replacing. Car has 168,000 miles i have rebuilt the entire front end , timeing and chain etc
So pleased to read these articles. I have a 2003 vow polo which initially drives for about a mile then starts spluttering and chugging, then white smoke bellows out from the exhaust. Eventually the acceleration just dies to nothing, it doesn’t stall but dies and and then splutters and chugs a bit more, sometimes if I turn the engine off and restart its ok for a short distance. The engine maintenance light comes on and won’t go off. I have had it to two different mechanics who say they can’t find the fault even after a diagnostic. Many years ago I had a gold that did the same thing and that was blocked fuel jets, I have told the mechanics that th symptoms are very similar but they haven’t investigated it. I don’t drive the car at the minute because it is too unreliable and have lost a bit of faith in mechanics. It’s had new plugs, full service and new front exhaust manifold/cat. Any advice would be gratefully appreciated.
Maybe a vacuum leak, those can be rare and annoying to diagnose. Also, checking the spark plugs is a good idea. Injectors are the easiest thing to check though.
But sometimes a car really needs a mechanic to get behind the wheel and feel out the issues and then go head deep into that engine. :)
Good article indeed.I drive a Nissan Almera and I recently picked up some of the symptoms mentioned .at one stage it almost cut off the engine and the engine light immediate went on and later went off when it was running smoothly.
Thanks for the advise ,I will buy ejector cleaner and have the plugs changed as well.
I have problem with my opel astra classic 1.6 the idle is low and goes off when accelerating, this after the mechanic replaced the pulley and crankshaft
I am not sure what could be the problem timing or fuel injectors
Jack I have a 2001 ford ranger 4.0 the truck will always start but after running it I shut it off it will start right back up, but if I let it sit around 20 minutes or so the first try no start, second try will try to start spitting and sputtering, third time maybe same, then it will start right up like nothing is wrong? I have changed MAF,TPS, IPS,AIR FILTER FUEL FILTER, AND when sitting in gear at a stop for a long time feels like it will stall I give it gas and bogs out when I get going again it wi clear up ‘s you help bin doing this over a year know,thanks
Did u get a solution . I have the same problem on my ibiza
If you cycle the key several times just enough to turn the fuel pump on and it starts on the first ignition start after that my experience with fords is it is a fuel pump beginning to fail.
I am all the way in South Africa and your article is very much covering all the problems I am experiencing on my mini cooper S, 2008.
I am thinking of using the additive injector cleaner.
Can you recommend any top 3 good products that I can buy (subject to availability down here in South Africa).
I have listed the highest rated products on the front page: https://fuelinjectorcleanerhq.com/
You can also read some reviews: https://fuelinjectorcleanerhq.com/product-reviews/
As for availability in South Africa – I’m afraid I don’t have much knowledge about that. Though Amazon can ship a lot of products overseas and many of these products might also be on sale locally. I suggest you check out some local online stores or car shops in your area.
I am from South Africa. I own a 2014 Nissan micra 1.2. I Noted that misfires and also I am spending double on fuel per day. Do you recommend I replace the fuel fitters? For some reason I have no lights and the computer is not picking any errors.
I was getting a bit of stutter on my vectra 2006 when lightly accelerating and then limp mode when higher rev during an over take.
I thought it was something to do with fuel because of the stutter, used Wynn injector cleaner in my tank and instantly the car is running smoother and no stuttering!
Injector must of been a little clogged!
Awesome info! My car a 2003 Galant are having some of these issues. However, my car won’t start unless the gas pedal is pressed. If I release the gas pedal it dies. As long as the gas pedal is down it will run. I had a few people tell me it has to be the injectors or MAP/VAF sensor. What’s your opinion on this Jack?
Those are definitely two possibilities. Adding some injector cleaner that only costs a few bucks is the easiest method to try first, to see if it helps – everything else is pretty much a job for your local repair shop guys, unless you’re mechanically adept yourself.
A lot of places do basic diagnostics for free or very cheaply, so it’s often a good idea to have the repair shop guys take a look, even if you’re not planning on investing any serious money with them.
Rod did you get this fixed? I am having the same problem with my 2004 Lancer…..Especially in the morning.
Jack please advice, mine has a very slight jerking at around 40Km/h and also sluggish acceleration.
Your Msg is clogged with oily substance get in injector cleaner
Start the vehicle ask some to hold the accelerator pedal,the Spray the open map very well,your car would bounce back.