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Rev limiter


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Has anyone else noticed a strange odor after bumping up against the rev limiter in first gear? Sort of smells vaguely like a stockyards...sort of.

 

Doesn't make the odor if I shift below the limiter. Could it be the cats being fried?

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Just an uneducated guess and really a WAG (wild azzed guess) but maybe the unburned fuel being passed back when the system shuts down at 6250 rpms? Maybe the gasoline in your area has a higher sulfur content?

 

Since there is no peaky cam affect in the stock GT-500 or straining sounds emanating from the engine as it nears the redline, I’ve hit the cutoff several times myself in the lower gears. However I never noticed any smell other than the fact I may have sh*t myself the first time it happened thinking I had blown my motor. :doh:

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Just an uneducated guess and really a WAG (wild azzed guess) but maybe the unburned fuel being passed back when the system shuts down at 6250 rpms? Maybe the gasoline in your area has a higher sulfur content?

 

Since there is no peaky cam affect in the stock GT-500 or straining sounds emanating from the engine as it nears the redline, I’ve hit the cutoff several times myself in the lower gears. However I never noticed any smell other than the fact I may have sh*t myself the first time it happened thinking I had blown my motor. :doh:

 

 

Thanks for info, Bill. I suppose it must be the local area gas. First time I smelled the odor thought there must be a stockyard somewhere around.

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Thanks for info, Bill. I suppose it must be the local area gas. First time I smelled the odor thought there must be a stockyard somewhere around.

 

 

I too have noticed this. I usually experience it after partial throttle first gear then full throttle second gear. I am in an area in texas where we have 10% ethanol.

 

My first guess was that it was the clutch. Under full acceleration with traction control ON. I thought maybe the clutch would slip a little due to the traction control. But, maybe it is the kind of gas?

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Just an uneducated guess and really a WAG (wild azzed guess) but maybe the unburned fuel being passed back when the system shuts down at 6250 rpms? Maybe the gasoline in your area has a higher sulfur content?

 

 

The rev limiter works by shutting off injector pulse, not coil pulse so there's no excess or unburned gas to dump and overload the Cat/s.

 

A rich mixture GENERALLY is described as a rotton egg odor.

 

By "Stockyard" do you mean like cow shit or like rotton eggs?

 

Rotten egg smell is from the sulphur but "Stockyard"....uhhhh, maybe you shit your pants? <chuckle>

 

 

Phill

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The rev limiter works by shutting off injector pulse, not coil pulse so there's no excess or unburned gas to dump and overload the Cat/s.

 

A rich mixture GENERALLY is described as a rotton egg odor.

 

By "Stockyard" do you mean like cow shit or like rotton eggs?

 

Rotten egg smell is from the sulphur but "Stockyard"....uhhhh, maybe you shit your pants? <chuckle>

 

 

Phill

 

 

 

Have you ever driven by a packing house stockyard? That kind of funky odor. I don' "think" it could be clutch. Or brake pads. Very mysterious. Thanks for the info on how the limiter works Phil, by cutting off the fuel. I was hoping it did that rather than doing something with ignition.

 

I did smell something dead in my garage a couple months ago. Maybe a mouse got up into the engine and got killed and is being cooked by exhaust at high power.

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Have you ever driven by a packing house stockyard? That kind of funky odor. I don' "think" it could be clutch. Or brake pads. Very mysterious. Thanks for the info on how the limiter works Phil, by cutting off the fuel. I was hoping it did that rather than doing something with ignition.

 

I did smell something dead in my garage a couple months ago. Maybe a mouse got up into the engine and got killed and is being cooked by exhaust at high power.

 

 

Weird-er things have happened. I had burnt plastic smell forever and could never figure out what it was. I finally got dirty and climbed all under my car to find a small portion of a plastic bag was slowing melting away on top of my exhaust...Happy hunting!

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I did smell something dead in my garage a couple months ago. Maybe a mouse got up into the engine and got killed and is being cooked by exhaust at high power.

 

 

I've pulled a number of dead mice out of heater core boxes. They climb in the vents and get near the warm core after you shut the car down and get out. Then when you start the car and put the heater on, they get baked with ~230d heat at the core. And yes, they do stink....like dead animal stink.

 

By some chance, do you notice the smell more with the heater on?

 

 

Phill

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I've pulled a number of dead mice out of heater core boxes. They climb in the vents and get near the warm core after you shut the car down and get out. Then when you start the car and put the heater on, they get baked with ~230d heat at the core. And yes, they do stink....like dead animal stink.

 

By some chance, do you notice the smell more with the heater on?

 

 

Phill

 

 

Do you mean they get into the system from within the car? The vents, I mean. Or are there exterior vent inlets that do not have a shield or guard grate at the opening(s)? Or a filter which would block ingress?

 

No, the heater was not in use, but the climate sys was in use. What gets me it's only after a high power blast up to or near the limiter. Within a couple minutes or so the odor slowly starts becoming noticeable in the cabin.

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Do you mean they get into the system from within the car? The vents, I mean. Or are there exterior vent inlets that do not have a shield or guard grate at the opening(s)? Or a filter which would block ingress?

 

No, the heater was not in use, but the climate sys was in use. What gets me it's only after a high power blast up to or near the limiter. Within a couple minutes or so the odor slowly starts becoming noticeable in the cabin.

 

 

From inside the car. They climb up the floor vents into the heater box. I've found dead mice, nests, mouse crap, etc. in customer cars.

 

I hate to tell you what it sounds like but....it *sounds* like the start of a Catalytic Converter failure. The engine gets a very rich mixture under load/power and usually the Cat's are efficient enough to convert the HC/CO but when they start to lose their efficency, even "normal" richness overcomes them.

 

What year car? Check your owners manual because I *think* cats are one of the items covered for a LONG period under the Fed. Emissions Warranty.

 

 

Phill

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