nathan944

OK..... Car starts and runs just fine, fuel pump makes normal sounds. When it gets hot (and I mean like when it is driven for 1hour or more the fuel pump starts to make a louder humming (buzzing) noise. At this point it feels like the car does not have the power that it did before the fuel pump got louder. Can this be a FPR? Can too much fuel pressure cause strain on the pump and decrese performance. Also my gas mileage is horrible.

nathan944

anyone?

Chris_924s

Bad Gas?? Check your plugs- they will tell the story for you.

FWIW- what plugs are you running? The fuel pump may have excess backpressure, (FPR is a culpriit- I have a spare if you need one) causing the fuel pump to moan.

nathan944

the plugs I have are bosch platinum

It is still doing it.... Also when I remove the gas cao I get LOTS of air pressure coming out. I really would like to know what it could be before I start spending money. Fuel pump probably has less than 6K on it so I hope I can rule that out.

Manning

I have had two fuel pumps on my car, the original and a brand new one and they both got loud when it was hot outside. However, mine did not really cause any performance issues. And both were used with a new FPR

As has been said, FPR could be bad. I seem to recall when they go bad they allow way too much pressure

shmucklebuckle

I haven't run them, but I've read around here that the Bosch platinum plugs run like poop in our cars. I just bought the copper ones. Works as good as it should I suppose. Maybe try putting those in?

jaycm

the fuel filter may need changing. i would change it first and see what happens. it sounds like the pump is working against some sort of blockage. also is there a filter screen in the tank? there may be trash in the tank that after a while is being sucked into the screen and limiting the fuel flow.
jay

nathan944

Is there any type of cleaner than I can dump into the gas to clean it all out?

meanmaroon951

Have you changed the regulator?

icat

You can run fuel injector cleaner through the tank, however, if the fuel filter is really clogged then it needs to be replaced. If that is the case, after you get it running right again make sure to run a good grade and brand of gas. There is a reason Porsche recomended Chevron's fuel additive Techron, and their gas comes with it.
I'll second the comment on the platinum plugs - toss 'em and go with copper. For what ever reason, the platinum plugs don't work well in our cars.

jaycm

since you can drain the tank, i would do that. the additive will not do anything for trash and stuff. flush the tank with fresh fuel, then fill with fresh fuel. i'm not sure if there is a drain plug or if you disconnect the fuel hose running to the pump. i think on my 928 i had to use the ole hose disconnect program. it's been a while and i don't remember. anyway, i would do this before trying to run the car on the fresh filter. if there is a lot of fuel in the tank, you can filter the trash out of the fuel you drain out and run it in your lawn mower or something.
jay

nathan944

The fuel filter was replaced with the fuel pump

Is there any easy way to get this screen out and clean it?

jaycm

i have not done any fuel tank work on the 944. maybe someone else that has been in their tank recently can help. if not, see if you can find an exploded view of the fuel tank and see what you can find. on my 928 there was access under the rear hatch carpet. the whole sending unit gismo can be removed from inside the car. i was able to look down into the tank and see if there was junk in it. i then drained all the fuel out from under the car and the junk flowed out with the fuel.
if there is a bunch of crap in the tank, there is a good chance that your new filter may be stopped up also.
jay

nathan944

I just hooked up my fuel pressure guage and the pressure readings were right on. I guess its back to the drawing board with this thing.

gtroth

I would have said FPR, but no with normal pressure. When my Fuel Pressure Regulator went, the fuel pressure at the rail went to, I don't know, ~100PSI (pegged my meter). This caused my fuel pump (which was only a year old) to start groaning. I could only ever hear it from inside the car. New FPR and all quiet now.