Originally posted by bigx01
i can get any fi manual to knock when its at idle. it's all practice and easy to confuse the computer with the load change. practice a little and
everyone can do it in any car.
i happen to know a thing or two about distillation of hydrocarbons and what boils at what temp and pressure. lets just say i have operational
experience with the distilation of hydrocarbons
vapor lock can and does happen with an electric fuel pump, if it has to pull gas from the tank and the rvp is to high then you'll only be pulling
vapors. remember the lower the pressure, the lower the temp things boil at, give off more vapor, when your suction is lowering the pressure . if the
pump is in the tank then it wont. although. with the summer rvp at only 11.5 psi (as low as 9psi in some places) then you probably wont have it
happen. winter rvp can be as high as 15psi and as low as 13.5 psi.
[edit on 3-5-2006 by bigx01]
Being able to trick the computer and get the car to ping strikes me as interesting, but not particularly useful.
I agree that you can get vapor lock with an electric fuel pump.
Especially so when the pump is mounted forward and perhaps up on the firewall.
All of the electric fuel pumps I've dealt with - and that's most of them - recommend the pump be installed to the rear so it's pushing fuel instead
of pulling it.
If the pump is gravity (as in a drag race car with it's tank outlets at the bottom of the fuel cell) fed or siphon fed (top outlet tank or fuel cell)
the pump has fuel at the inlet and has only to push it up to carb or injectors.
I've never had vapor lock with a rear mounted electric pump.
Anyway, it looks like you're a part of the refining process.
I believe California is still using MTBE in their gasoline.
After what, four years or so of being outlawed by then governor Gray Davis?
With the proviso that the refineries could use up remaining stocks of MTBE.
They must have had a lot of it on hand.
I note that MTBE gasoline gets just about 10% less mileage than does straight gasoline.
That was true in both of my vehicles.
It was easy to track because I use gas mileage as an indicator of how well the engine's running.
Since MTBE didn't clean up the exhaust 10% and things only improved a couple of percent - if that - from what I understand, the only reason for MTBE
was as a profit boost for the oil companies.
Not to mention that MTBE is such a fierce polluter of the water table.
It enters the water supply and doesn't go away in any reasonable length of time.
As a small aside and taking note of the recently retired Exxon CEO's 400 million dollar retirement package I see that one of the retirement perks was
that Exxon continue to pay his country club fees.
What a frickin cheapskate.
400 mill and he can't cough up his own country club fees?