never heard this one. i was told when my gas tank drops below half tank or so, the pcm goes into some efficiency type setting or something? and wont let the truck run its best because it thinks its low on fuel?

this came up in coversation about wieght of a full tank of gas and 1/4 mile times. vs. 1/8th tank or so. i couldn't say i knew he was wrong so i didn't.

all i could think was i know where to go to find out if its valid or B.S..... 04 5.3.

 

Sounds like b.s.
I know LS1edit doesn't have every single table to reprogram in it, but there are many...and there is no pcm logic like this in any tables.

Oh I just thought of this though...Under cruise conditions the pcm will see that the tps% has not changed in quite a while and it will lean out the air/fuel ratio some for better gas milage. (not sure exactly what it referrences to do this) And it only does it on the Aussie cars. EPA doesn't like us doing it in the states I guess.
-maybe that is what they were thinking about???

 

The only thing I ever heard has to do w/keeping the fuel pump submerged. Someone in the parts industry said that you should never let your tank go past half a tank very often because it will shorten the life of the fuel pump. I never really believed that though.

 

How would you drive anywhere then

Just don't floor it when it's at 1/4 tank or less. Ya these pumps stay relatively cool compared to most setups. The return fuel falls right on top of the motor keeping it cooler. Just don't run the engine bone dry. That will cause that motor to fail prematurely.

 

this was totally about how much gas was in the tank. like if you had 1/8 tank, your pcm could tell that fuel supply was low so it somehow didn't allow capeable engine performance????? but if your tank is full the pcm somehow? recognizes the abundance of fuel and lets er rip.........??shitidontknow.

 

I don't think it is true

 

I don't either.