WHat exactly causes fuel cut?

jetjock

creepy-ass cracka
Jul 11, 2005
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Talk about off topic ;).

You mean funny ha ha or funny odd? Funny as is humor would be смешной. Say "smeh-shnoy". Funny as in odd would be страннй which (in Cyrillic) looks and is pronounced very much like strange: "stranni".

Russian is a very rich language, much more so than English. Especially when it comes to expletives. It's just that the grammar is nuts. For example everything has gender and different words are used depending on if you're a stranger or know the person. It's also a very phonetic language. Words are pretty much pronounced just as they are written.
 

drjonez

Supramania Contributor
Mar 31, 2005
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hmmmmm.....

FCO is present to save the car in the event that something goes wrong....unfortunately that doesn't play well with upping the boost.

FCO has NOTHING to do with actual fueling (no, larger inj. or fuel pumps won't make it go away...), it's merely triggered when you get enough inputs "right". as far as what "right" is, that's hard to say. FCO occurs at AFM output near 1500 Hz, colder temps will make it happen @ an earlier boost level (colder temps = more dense intake charge = greater chance for running lean).

ECU inputs that can affect FCO:
-mass flow (i.e. AFM output)
-RPM
-intake temp
-coolant temp
-TPS
-baro
 

Jeff Lange

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Mar 29, 2005
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whopwood said:
I always thought fuel cut was the result of running off the map. Basically, the computer says "I don't know what to do based on these input values".

Nope, the ECU has a lot of programming past fuel cut, and knows what to do with values past it, but it never gets to use them because of fuel cut. If you go with a modified ECU via Techtom, etc, you get to access these wonderful values ;).
 

drjonez

Supramania Contributor
Mar 31, 2005
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jetjock said:
Can the good doctor supply his references regarding that? I'm curious about something.

personal experience. you can clamp AFM out, but you still end up w/FCO. you can head to a cooler or higher clime and change where FCO is. the real thing to do would be to call up reg and ask him....seeing as how he has access to the ECU code.
 

drjonez

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supradan22 said:
So what does a Fuel Cut Defenser do to the ecu to keep it from cutting the fuel?


great question. i don't know. i know it's more than a simple frequency clamp....IIRC the FCD gets an RPM input and maybe TPS? i was trying to get one to see exactly what it does....
 

Nick M

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Sep 9, 2005
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GrimJack said:
Dammit, you made me go look it up! :biglaugh:
I was just making an assumption that turned out to be correct. The assumption was he was being a bit of smart ass since people dont understand plain english, try a foreign language. Or something like that.:biglaugh:
 

Ckanderson

Supramania Contributor
Apr 1, 1983
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jetjock said:
In the case of a turbo car the AFM sends out a frequency (not a voltage) proportional to metered airflow. The ecu is programmed to cut injection when this frequency exceeds a certain amount. It's a function of the TCCS's fail safe mode. That's what happens. Why it needs to happen has already been explained but the designed purpose is to protect against various forms of wastegate failure.


Exactly... end thread