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Old 01-13-2013, 10:18 PM   #391 (permalink)
phunk
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Join Date: Mar 2009
Location: Chicago
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Quote:
Originally Posted by Mr&Mrs View Post
Sorry not trying to thread jack, but I had a little issue and figured you guys could help.

Question is about fuel starvation. What is the consequence (or car behavior) from the fuel starve? I will give some detail on what I experienced a few days ago.

I was accelerating up an on ramp to the interstate, was in 4th gear rolling onto the throttle and coming out of it planted. About 50 feet into the straight at 5k rpms it reacted like I hit rev limiter. Vitals looked great so after a mile or so I done a WOT in 4th again and it did not happen.

Later I took another right turn but much shorter maybe a 80 degree 100-125 FT turn. Same thing as I came into the straight around 5k rpms it acted like I hit the rev limiter. I played around all the way home and it did not do it again. Only after these right turns.

That said, I know a long sweeping right turn causes issues. What are the issues exactly (fuel cut car reaction)? Does it hit you while in the corner? Or in my instance's I was in and out of the corner quickly so the lag hit me as I was coming into the straight?

I had a couple dots over a quarter of a tank of fuel remaining, also the car is TT.
Thanks for any input I will rep when it recharges I ran out for the day!
The fuel level you were at was well into the fuel starvation risk area. Basically, once the gauge no longer reads topped off, you are at risk, and the risk increases the lower you go.

you often will not realize that you are in the middle of fuel starvation while in the right hand turn, and then you will encounter it as soon as you go to give it gas. it feels as if the gas peddle is not connected to anything because the trans is in gear, the engine is spinning, but it is not responding to giving it gas. at this point, the engine is only spinning because you are in gear, if you took it out of gear, the engine will die unless the fuel pump happens to grab some fuel as youre letting off.

when you make the hard or long right, the fuel sloshes over to the drivers side of the tank. If the turn was aggressive enough, you can get nearly all the fuel to go over there. so even though you have straightened out after the turn... most the fuel is over on the other side of the tank, and when you go to give it gas there is such a little amount that the pump cannot meet the engines needs.

it takes the system time to recover the fuel from over there. there is a little siphon that is powered by a venturi effect in the fuel leaving the fuel pressure regulator. it is constantly, and slowly, transferring fuel from the driver side to the passenger side where the pump resides. since it is required that the fuel pressure regulator be allowing fuel to bypass, if you are even low on fuel pressure, the siphon will die. this means you can actually transfer all the fuel to the other side, have the engine die, and there will be nothing you can do (short of adding more fuel into the tank) to get the fuel back to the passenger side. the car can actually be stuck on the side of the road until you bring it gas.
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