fuel delivery issues

[Fordmandan87]

any time i make a hard right with the tank at 1/4 tank or lower my x bogs, cuts out and sometimes dies i recently put a new pump, screen and sending unit in the tank. any theories

 

[Exploderpilot]

weird? filter?

 

[MrShorty]

Mine does the same thing when there's less than a gallon or so left. I know when I changed my fuel pump (with sender), the gauge changed how it read noticeably. Is it possible that with the new pump (and sender if you changed them together) that 1/4 tank on the gauge means "last gallon or so"? When you get to 1/4 tank how much does it take to fill?

 

[Fordmandan87]

Newer filter changed roughly 6000miles ago filled it up from empty and it filled 17.8 gallons pump was bought 3 years ago by previous owner however i did have to install a new sending unit could the older pump or sock have any effect on the performance. I also am getting 28 psi regulated and 38 psi unregulated could a partially stuck regulater cause this

 

[MrShorty]

I wouldn't expect to be a bad regulator, and those pressure readings don't look real bad to me, unless the pressure drops further as engine speed/load increases.

When you had the tank out, do you recall seeing a "swirl" molded in the bottom of the tank? The fuel pump is supposed to sit in the bottom of that swirl. When there is low fuel in the tank, that swirl is supposed to hold enough fuel at the pump pickup to prevent it from stalling when cornering and such. If the pickup doesn't reach the bottom of the tank or similar, then it may start sucking vapor.

17.8 gallons to fill from E or to fill from 1/4 tank where the problem shows up? 17.8 gallons out of a 19.x gallon tank means there isn't much in there. Depending on the exact design of the replacement pump, that may be as good as you're going to get. You may just need to make a habit of fueling up a little more frequently.

 

[mikeinri]

I'm with mrshorty. 17.8 gallons is probably further than you should really want to push it, that's asking for trouble...

If your gauge read 1/4 and it took 17.8, there's something odd going on, but it would be far easier to "recalibrate" your brain than taking stuff apart again. Just consider 1/4 to be Empty, and fill before you get there.

Hope this helps.

Mike

 

[Fordmandan87]

the only reason that i thought the regulater could be bad is the fact that it bogs in the morning to the point that it sound like its cutting out the engine runs rougher than i would like the vehicle did have the swirl but the metal part on the plastic tank is mostly gone but the is enough there to hold the sending unit in with no leaks.

 

[MrShorty]

Were those pressure readings you reported earlier from one of these "bogging and rough running in the morning" events, or were they from a time when the engine was running well? Is it still a question of only occurring when the fuel tank is near empty, or are we talking every cold start? Were those pressure readings all you did to test fuel delivery, or did you also do a bleed down test and a load test? What does the fuel pressure do (and how does the engine run) if you disconnect (and plug) the vacuum line to the FPR?

 

[YourNameHere]

If 1/4 tank = empty, then pop the lense off the instrument cluster, and pull the needle off and place it on F, after you fill the x up.

Have you checked the voltage on the TPS?

 

[Fordmandan87]

the pressure readings were taken during the middle of the day during the first start up i read that psi readings should be between 30 - 40 psi regulated 40 - 65 psi unregulated however it hauled ass with a plugged vacume line. however it stalled when the tank got low 1/8 or less

 

[markedman450]

This problem is happning to me too

 

[markedman450]

Has anyone solved this mystery cause my 01 is doing the same thing. Except once i get the tank below half way it starts stalling around slower turns, then fires right back up. Also when i try to accelerate it starts bucking like its gonna stall almost like a fuel cutout or fuel flooding. I had a pressure test done and i think for my year its suppose to be around 62, the test i had a garage do read 92! The fuel pump is new so im lost.

 

[e39dream]

might be your fuel pressure regulator is shot.

I have learned thru my work with german cars that in tank fuel pumps rely on the fluid to cool them and it is best for the life of the pump to keep it submerged fully.

I make it practice in my cars to add gas at 1/4 tank as if 1/4 tank were empty. easy to do and you wont burn your pump up.

I wish my truck would run, even if it did cut out a little

 

[Fordmandan87]

alright guys new development i filled up my tank to the tippy top and it now leaks out the seal for the sending unit. i also checked my vacume again and it idles around 17 in murcury how ever when it bogs it goes from 15 to 7-8 my new question what can that leaking tank do to my pressure and or vacume reading

 

[MrShorty]

A gas leak in the fuel tank should not have any effect on fuel pressure or engine vacuum.

 

[e39dream]

the sending unit and fuel pump are one unit. if you're leaking there it is possible that your flange has rusted and might need a new pump and or flange, or in bad case a new tank.

 

[Fordmandan87]

any body have a tank that is not rusted at the sending unit location

 

[Fordmandan87]

bump

 

[Fordmandan87]

ok guys i had a spare engine lying around and i replaced the iac the rm drop has stopped but it will still bog hmmmmnn any ideas

 

[Fordmandan87]

is it a possibility that this things timing is off