My Subaru Impreza owners manual states that running the vehicle close to E can damage the Catalytic Converter. How is this possible. Does the car run hotter when it's near E? The manual also says that racing the vehicle can damage the Cat also.
Does a nearly empty gas tank damage Catalytic Con?
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Originally Posted By: Hemi426
My only guess is that running it near empty could cause a sputter and resulting back-fire which could hurt the cat. You're guess is as good as mine about racing.
Correct. That's the Subaru reasoning. Don't know if you are the original owner, or what year your Impreza is, but there is a recall, on the '05 model at least, to correct that very problem. There is a valve in the gas tank supposedly to keep the car from sucking air and mis firing at low fuel level. Turns out this valve exacerbates the problem, so they just take it out.
My only guess is that running it near empty could cause a sputter and resulting back-fire which could hurt the cat. You're guess is as good as mine about racing.
Correct. That's the Subaru reasoning. Don't know if you are the original owner, or what year your Impreza is, but there is a recall, on the '05 model at least, to correct that very problem. There is a valve in the gas tank supposedly to keep the car from sucking air and mis firing at low fuel level. Turns out this valve exacerbates the problem, so they just take it out.
One of the reasons that they state racing can damage the catalytic converter is that many people will put race gas in the tank as many tracks dont carry regular unleaded. The tetraethyl lead plugs up the cats honeycomb core. This is what I think the manula is referring to.
If running a gas tank low to E harms the CAT then I'm in REAL trouble....
I go to the point where the light goes on and drive 50 miles further.
Not true!
Bill
I go to the point where the light goes on and drive 50 miles further.
Not true!
Bill
I'd be more concerned with ruining a fuel pump or sucking up dirt.
Originally Posted By: sunfire
Originally Posted By: Bill in Utah
If running a gas tank low to E harms the CAT then I'm in REAL trouble....
I go to the point where the light goes on and drive 50 miles further.
Not true!
Bill
Bill the myth buster.
I'm sorry, I must have missed your post where it has harmed your vehicle.
Can you direct me to it?
Next....
Originally Posted By: Bill in Utah
If running a gas tank low to E harms the CAT then I'm in REAL trouble....
I go to the point where the light goes on and drive 50 miles further.
Not true!
Bill
Bill the myth buster.
I'm sorry, I must have missed your post where it has harmed your vehicle.
Can you direct me to it?
Next....
Originally Posted By: demarpaint
I'd be more concerned with ruining a fuel pump or sucking up dirt.
Gas these days is filtered at the pump using spin on filters and as along as you follow a few rules;
1. Buy fuel from a station that sells a lot of fuel
2. Don't EVER buy fuel when the delivery truck is dumping fuel into the tanks (more for water as the filters don't work that well for water)
Quite a few vehicles don't even have fuel filters that are replaceable (they are in the gas tank) even though we are using injectors.
Take care, Bill
I'd be more concerned with ruining a fuel pump or sucking up dirt.
Gas these days is filtered at the pump using spin on filters and as along as you follow a few rules;
1. Buy fuel from a station that sells a lot of fuel
2. Don't EVER buy fuel when the delivery truck is dumping fuel into the tanks (more for water as the filters don't work that well for water)
Quite a few vehicles don't even have fuel filters that are replaceable (they are in the gas tank) even though we are using injectors.
Take care, Bill
I try not to run any less than 1/2 unless Im on a long trip. Simply for J.I.C. reserve. If Im on a trip I sometimes will run it empty. Usually I preplan fuel stops as well as food and hotels. There is no harm.
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The EPA makes them put that warning in there as well as the one about not roll starting the vehicle.
My sister had a 1988 nissan sentra. Did you know they still made diesel sentras in 1988? The owner's manual went on and on about not roll starting, unless you had the diesel, in which case, here's how to do it.
My sister had a 1988 nissan sentra. Did you know they still made diesel sentras in 1988? The owner's manual went on and on about not roll starting, unless you had the diesel, in which case, here's how to do it.
Originally Posted By: Bill in Utah
If running a gas tank low to E harms the CAT then I'm in REAL trouble....
I go to the point where the light goes on and drive 50 miles further.
Not true!
Bill
You're wrong, at least according to the recall from October 2009.
Quote:
Certain 2005-2008 Forester and 2005~2007 Impreza models require permanent removal of the one-way fuel valve located in the fuel tank. The valve is in a sub-chamber in the fuel tank and when the tank’s fuel level drops below 1½ gallons, the sub-chamber is intended to provide a reserve for the fuel pump during vehicle cornering. However, the one-way valve may inadvertently act in such a way as to prevent fuel from refilling the sub-chamber, failing to provide the intended reserve. If this were to happen, the fuel pump could momentarily draw air causing the engine to experience a sporadic misfire condition resulting in possible damage to the vehicle’s catalytic converter. (The “Check Engine” light will illuminate alerting the driver that the catalytic converter efficiency has degraded beyond an acceptable level and may be releasing air pollutants that exceed emission standards.) This Service Program will remove the valve. Program #WVL-22
If running a gas tank low to E harms the CAT then I'm in REAL trouble....
I go to the point where the light goes on and drive 50 miles further.
Not true!
Bill
You're wrong, at least according to the recall from October 2009.
Quote:
Certain 2005-2008 Forester and 2005~2007 Impreza models require permanent removal of the one-way fuel valve located in the fuel tank. The valve is in a sub-chamber in the fuel tank and when the tank’s fuel level drops below 1½ gallons, the sub-chamber is intended to provide a reserve for the fuel pump during vehicle cornering. However, the one-way valve may inadvertently act in such a way as to prevent fuel from refilling the sub-chamber, failing to provide the intended reserve. If this were to happen, the fuel pump could momentarily draw air causing the engine to experience a sporadic misfire condition resulting in possible damage to the vehicle’s catalytic converter. (The “Check Engine” light will illuminate alerting the driver that the catalytic converter efficiency has degraded beyond an acceptable level and may be releasing air pollutants that exceed emission standards.) This Service Program will remove the valve. Program #WVL-22
Well, done it every time with every vehicle I've owned (incl Subaru) and never a problem with it in my experience.
Looks like the valve is not needed and most vehicles don't have it.
If their is a engineering issue that is not because of running the vehicle low on fuel, its a design problem.
Bill
Looks like the valve is not needed and most vehicles don't have it.
If their is a engineering issue that is not because of running the vehicle low on fuel, its a design problem.
Bill
Guys, we're not dealing with a hare-brained myth that just materialized on the internet. This is right out of the manufacturer-written owner' manual. No, I don't think that this is a general problem that would occur in all cars, or perhaps per Bill's experience, all Subes. I suspect that generation of Impreza has an unanticipated issue with its tank and/or fuel system.
Originally Posted By: eljefino
The EPA makes them put that warning in there as well as the one about not roll starting the vehicle.
My sister had a 1988 nissan sentra. Did you know they still made diesel sentras in 1988? The owner's manual went on and on about not roll starting, unless you had the diesel, in which case, here's how to do it.
The EPA makes them put that warning in there as well as the one about not roll starting the vehicle.
My sister had a 1988 nissan sentra. Did you know they still made diesel sentras in 1988? The owner's manual went on and on about not roll starting, unless you had the diesel, in which case, here's how to do it.
Originally Posted By: Bill in Utah
If running a gas tank low to E harms the CAT then I'm in REAL trouble....
I go to the point where the light goes on and drive 50 miles further.
Bill
Exactly what I used to do until I ran out at the 40 mile mark! 500ft from the gas station. When I filled up it took 5 litres less than I figured it would. Now I know why. Luckily, no mis fire/ cat damage, just a 1000 ft walk! The local Subaru dealer has now corrected the problem.
If running a gas tank low to E harms the CAT then I'm in REAL trouble....
I go to the point where the light goes on and drive 50 miles further.
Bill
Exactly what I used to do until I ran out at the 40 mile mark! 500ft from the gas station. When I filled up it took 5 litres less than I figured it would. Now I know why. Luckily, no mis fire/ cat damage, just a 1000 ft walk! The local Subaru dealer has now corrected the problem.
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