fuel/car hestitation issues?

[hahaitzskippy]

ok installed a new BOSCH OE replacement fuel pump... hoping it would correct my "WOT CAR HESITATION ACCELERATION" problem...

the problem is worse when it is cold. when it is cold, i add a little bit of gas, and the car hits a wall as if i am hitting fuel cut or not enough fuel pressure. so i installed a new fuel pump.

car is a bit more responsive but...

it hums every so often. like its off and on. it would hum for a few secs then no hum. then 10seconds later, the hum would come back for about 5 secs and go away.

the hum is noticeable in the cabin.

any thing wrong with the fuel pump?

do i need change the dampener?

i am going to change the regulator this week... (mailman issues).

anyone think it might be the sending unit in the tank?

[jlevie]

A hesitation, or stall, off idle is most commonly caused by intake leaks. A smoke test will find them.

[hahaitzskippy]

idles is smooth and spot on. i have no problems with idle.

and how do you do my own smoke test?

[jlevie]

To do your own smoke test you first need a smoke machine. The least expensive commercial one I know of is about $1000. There are some descriptions of home made ones on the web, try a search. Then you need a plug for the exhaust and an adapter that replaces the AFM and has nipple for introduction of smoke. Feed in smoke until the pressure in the intake is 2-4psi and hold that pressure for at least five minutes to allow smoke to work it's way into the crank case if there leaks there.