Can a clogged air filter actually "Damage" a fuel injected engine

2WheelNut · Mar 13, 2013

First off...let me say that I'm not suggesting that you should let your filters get clogged and I don't want to get into a discussion of how often you should change your filter (already another thread you can participate in you feel the need there)

What I DO want to understand is if you can actually damage a fuel injected engine by not giving it proper air flow.

The key words in this scenario are "damage" and "fuel injected"

I know you can damage a carbeurated engine with too little air as it will run rich and can leave deposits in the cylinders that will work it's way into the oil. My question is whether or not that applies when you move to fuel injection.

I'm thinking there is no way it will be damaged. I'm thinking this because a fuel injected engine will just lean out the fuel mixture to go along with the lower oxygen that it is reading from the O2 sensor until it gets to a point where it can't go any leaner and then it just won't run. In this scenario, your power will certainly decrease as there will be less fuel burning and therefore less power created, but I don't see where it would cause permanant damage, only a performance loss while the filter is restricted. This does assume that the injectors can deliver a variable fuel amount all the way to the point where the engine won't run at all. I'm not sure if that is true or not so that is the one piece of my scenario that I feel I have the most room for error.

Am I wrong? What am I missing?

Oh...and by the way...In case you are wondering why I'd want to know...I was thinking about the whole mouse nest in the filter thing and wondering if something like that would actually "damage" the engine or if it would just degrade performance until you figured out you had a mouse nest in your filter. Obviously no one in their right mind would ever WANT to let their filter get that clogged.

SteelTraveler · Mar 13, 2013

I don't know the answer, but you've posted a very interesting question. You might consider posting it on the Tech Board. That's where the guys who know their stuff hang out.

31261 · Mar 13, 2013

A dirty or clogged filter can rob the engine of performance. About the only way an air filter related cause of engine damage could happen is for it to have a hole in it, or not sealed properly in its holding box and allow dirt and junk into the engine.

Normally all a dirty filter does is rob the engine of performance. And it takes a very, very dirty one to do that.

Bucfan11 · Mar 13, 2013

Kit Carson said:
And it takes a very, very dirty one to do that.

Except on this bike. When I was a young man I discovered that an air inlet about the size of a quarter would only let enough air in to feed 4 carbs if the air filter was like new...always. I finally cut larger holes in the airbox.

CB650

HBarlow · Mar 14, 2013

I don't KNOW but suspect that the GW fuel injection is designed to work within certain programmed parameters of engine rpm, air flow, and ignition timing. I think if air flow is severely restricted as in the hypothetical situation of a clogged air cleaner the fuel injection system will not be able to fully adjust fueling sufficiently to lean the mixture down to match the limited airflow. My guess is some excess fueling can occur and some cylinder washdown could result from an overly rich mixture.

If someone knows better I'd like to read about it.

Bucfan11 · Mar 14, 2013

HBarlow said:
I don't KNOW but suspect that the GW fuel injection is designed to work within certain programmed parameters of engine rpm, air flow, and ignition timing. I think if air flow is severely restricted as in the hypothetical situation of a clogged air cleaner the fuel injection system will not be able to fully adjust fueling sufficiently to lean the mixture down to match the limited airflow. My guess is some excess fueling can occur and some cylinder washdown could result from an overly rich mixture.

If someone knows better I'd like to read about it.

:agree:

sur48 · Mar 14, 2013

:agree:

HBarlow said:
I don't KNOW but suspect that the GW fuel injection is designed to work within certain programmed parameters of engine rpm, air flow, and ignition timing. I think if air flow is severely restricted as in the hypothetical situation of a clogged air cleaner the fuel injection system will not be able to fully adjust fueling sufficiently to lean the mixture down to match the limited airflow. My guess is some excess fueling can occur and some cylinder washdown could result from an overly rich mixture.

If someone knows better I'd like to read about it.

I agree no air means a rich mixture and a cooler cylinder and un burned fuel hitting exhaust manifold turning to black exhaust. A super dirty air will over time and a wet environment the motor will suck a hole in the filter somewere and dirt and sand will pass causing cylinder scoring and eventually causing blow by and loss of compression .
My thoughts to your question

WING1T · Mar 14, 2013

I'm sure that this FI engine works like all other FI engines. The fuel delivered will be a function of the air flow detected by the MAF (mass airflow sensor). If the MAF senses a lower air flow, the computer should calculate a new fuel feed rate based on the AFR (Air to Fuel Ratio) curve programmed into the ECU. At some point, there will not be enough airflow to sustain combustion combined with the lower fuel rate you will get rough idles, stalls, sputters, backfires, etc as unburned fuel hits the exhaust manifold and combustion cannot be maintained. Can you damage the engine to the point of needing repair? My humble opinion is no, you won't be able to keep it running that long. Can you damage other things? Absolutely, you will definitely need new spark plugs as you have probably fouled the current ones out. O2 sensors can also get gummed up this way if it's left uncorrected for too long. Catalytic converters will also fall prey to shortened life spans if the mixture is too rich for too long, although this component will probably not be limiting, more likely you will reach some other failure that will prevent the engine from running.

Your best bet is not to ignore symptoms like unexplained power loss, shuttering, a sudden drop in fuel mileage (with normal driving), or stalling and check your air filter first. Another thing you can do, is put your hand in the exhaust stream. Smell your hand. If it smells like gas, your running rich for some reason. If it smells like oil, well friend, you got other issues. The former can indicate a clogged air filter, the latter a head gasket or piston issues.

It should also be noted that a dirty MAF sensor can have symptoms similar to a clogged air filter, so it's always a good idea to put a little brake cleaner on a rag and CAREFULLY (can't stress that enough) wipe the sensor down whenever you have access to it.

DISCLAIMER: I am not a mechanic, only a car nut, soooo... this is only my $0.02, see your doctor if your symptoms last for more than 4 hours, and YMMV.

megatwin · Mar 14, 2013

I agree that the fuel injection does not have the capability to lean an engine out to the point of damage due to a dirty air filter,it's gonna run richer if it can't get air.
Worst case,if the filter gets too clogged,the suction can actually pull fine dust particles thru it,and that will damage your engine!

Racer57 · Mar 14, 2013

WING1T said:
I'm sure that this FI engine works like all other FI engines. The fuel delivered will be a function of the air flow detected by the MAF (mass airflow sensor). If the MAF senses a lower air flow, the computer should calculate a new fuel feed rate based on the AFR (Air to Fuel Ratio) curve programmed into the ECU. At some point, there will not be enough airflow to sustain combustion combined with the lower fuel rate you will get rough idles, stalls, sputters, backfires, etc as unburned fuel hits the exhaust manifold and combustion cannot be maintained. Can you damage the engine to the point of needing repair? My humble opinion is no, you won't be able to keep it running that long. Can you damage other things? Absolutely, you will definitely need new spark plugs as you have probably fouled the current ones out. O2 sensors can also get gummed up this way if it's left uncorrected for too long. Catalytic converters will also fall prey to shortened life spans if the mixture is too rich for too long, although this component will probably not be limiting, more likely you will reach some other failure that will prevent the engine from running.

Your best bet is not to ignore symptoms like unexplained power loss, shuttering, a sudden drop in fuel mileage (with normal driving), or stalling and check your air filter first. Another thing you can do, is put your hand in the exhaust stream. Smell your hand. If it smells like gas, your running rich for some reason. If it smells like oil, well friend, you got other issues. The former can indicate a clogged air filter, the latter a head gasket or piston issues.

It should also be noted that a dirty MAF sensor can have symptoms similar to a clogged air filter, so it's always a good idea to put a little brake cleaner on a rag and CAREFULLY (can't stress that enough) wipe the sensor down whenever you have access to it.

DISCLAIMER: I am not a mechanic, only a car nut, soooo... this is only my $0.02, see your doctor if your symptoms last for more than 4 hours, and YMMV.

:yes1:

The GW ECM is limited in what it will compensate for. It will run too crappy before any serious damage occurs.

2WheelNut · Mar 14, 2013

Thanks for the input. I think the consensus is essentially what I suspected....you will notice degraded performance and know something is wrong LONG before you are going to damage your engine.

Just as always....if something seems to be wrong....go figure out why. If not, do normal maintenance and ride.

Can a clogged air filter actually "Damage" a fuel injected engine

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