back with fuel problems again

[ebourd]

so i changed fuel pump and all relays this is my second fuel pump but pressure is dropping to 20 or less psi any help is welcome 92 ford mustang GT 5.0

[dreamstang]

thats a wierd problem. hmmmm....

does this happen gradually? how long between pump changes?
are the pumps autozon/ebay specials?

[deadsp0t]

Regulator?

[ebourd]

this pump has been in there almost two weeks and yes autozone been fine till today my buddy suggested trying a higher amp fuel pump relay

[dreamstang]

Originally Posted by ebourd

this pump has been in there almost two weeks and yes autozone been fine till today my buddy suggested trying a higher amp fuel pump relay

are you getting 20 lbs at the scrader or the rails? if you can check both, that will help eliminate the regulator as dead suggests.

what brand pump is it? i would try to get a walbro at least.

[ebourd]

not sure what brand and yeah 20lb or less at rails ill check before regulator

[Trojan Horse]

I agree with the regulator being a possibility.

Also ensure the filter is good and not clogged up.
You may also have one or more injectors sticking open.
Notice any black smoke or stumbling when you start it?

[ebourd]

no to the black smoke and got a bbk adjustable pressure reg hope it works going in morning

[ebourd]

Ok bbk and newer injectors on used but a lot less mileage then mine see what happens

[ebourd]

Ok well guys it did it again Idk what else to try my buddy suggested higher amp fuel and ac relay I'm stump I have changed everything

[ebourd]

anyone got any ideas

[dreamstang]

check the tfi module. im not positive it can do this. but i think it can. there should be a testing procedure in haynes/chilton.

---------- Post added at 10:03 PM ---------- Previous post was at 10:00 PM ----------

also did you check pressure at the schrader valve just to see? that will gurantee if you pump is pumping properly of not.

[ebourd]

tfi ? not sure what that is but im willing to try anything

[dreamstang]

tfi module aka igniton module. its mounted on the side of the distributor. it tells the ecu when to turn the pump on. it also has other functions to.

[ebourd]

wont go over twenty psi when its angry and added the bbk pressure reg are u talking about ignition module i already change that along with relays coil dam near anything any one has said try

[dreamstang]

Originally Posted by ebourd

wont go over twenty psi when its angry and added the bbk pressure reg are u talking about ignition module i already change that along with relays coil dam near anything any one has said try

before you changes parts that we suggest you can test them first. almost all those parts are testable.

i hate to say it but if you cant get over 20 lbs before the regulator. you either got a bunk pump or have a clogged filter or kinked line.

once this problem occurs does it stay like that? or is it intermittent?

[ebourd]

intermittent it will go for a few days fine and then in the heat of the evening it does it and i believe its the return side for the pressure at 20 psi

---------- Post added at 08:20 PM ---------- Previous post was at 08:17 PM ----------

it also was doing it with last pump
seems like when it cools it works again

[dreamstang]

Originally Posted by ebourd

intermittent it will go for a few days fine and then in the heat of the evening it does it and i believe its the return side for the pressure at 20 psi

What do you mean return side? The pressure on the return doesn't matter.

Do you have rubber line on the return? If so try linking it and seeing if your pressure raises. If it doesn't then the pump isn't doing its job, I think.

Next time this happens you need to check voltage at the pump. It sound like to me that your losing voltage somehow at the pump intermittently. You may have to trace that down with a meter. But you will only be able to find the problem when it occurs, most likely.

[ebourd]

here is pressure gauge

[dreamstang]

Originally Posted by ebourd

here is pressure gauge

I can't tell what line its on. But its hard to tell in the pic. But you have 35-38 lbs at that time? Must be when its running right?

[ebourd]

yeah 35-40 when running correctly

[ebourd]

Anyone with ideas

[90mustangLX]

Did you try to clean the tank before installing the new pump? I know on the advance and auto zone pumps there's a little screen on the pump itself and they always get clogged and end up choking/burning the pumps up. My 87 did something similar to this. It would drive fine then out of the blue if you stabbed the throttle it would just pop and crack lie it was starving for fuel.

Checked the pressure when it did this and at idle ur was around 40 psi, nail the throttle and bam down to 10 lbs of pressure. Turned out the little screen was clogged and was causing the pump to overheat. Put a new one in and it fixed it.

[dreamstang]

Originally Posted by 90mustangLX

Did you try to clean the tank before installing the new pump? I know on the advance and auto zone pumps there's a little screen on the pump itself and they always get clogged and end up choking/burning the pumps up. My 87 did something similar to this. It would drive fine then out of the blue if you stabbed the throttle it would just pop and crack lie it was starving for fuel.

Checked the pressure when it did this and at idle ur was around 40 psi, nail the throttle and bam down to 10 lbs of pressure. Turned out the little screen was clogged and was causing the pump to overheat. Put a new one in and it fixed it.

You maybe on to something.

[sixpac]

Long shot but have you checked your timing? My bronco had a problem and we adjusted the timing and then didn't have a priblem

[ebourd]

So here's an update voltage at pump drops to around ten volts when it happens can't seem to find the cause though

[dreamstang]

Did you check voltage at the before and after the relay also? That will help determine the spot your losing voltage.

And its been a while. Did you say you checked ignition(tfi) module and pip(hall) sensor?

Also check voltage on the battery when it happens. Whatever the alternator/battery are putting out, is all the whole system will have.

[Trojan Horse]

May be that the filter sock on the fuel pump in the tank (like 90mustangLX said) is collapsing from being plugged up.If there are no wiring problems, then that is likely the cause.
I bet if you had an ammeter on the pump it would jump way up when that happens.

[ebourd]

Hey trojan need ur help I ran another wire even put a switch for fuel its been working fine all week and today it died again like a block from my house gonna change filter again then I guess its back to the third pump fuel isn't coming up to twenty psi right now

---------- Post added at 07:16 PM ---------- Previous post was at 06:42 PM ----------

Or anyone really

[Trojan Horse]

Originally Posted by ebourd

Hey trojan need ur help I ran another wire even put a switch for fuel its been working fine all week and today it died again like a block from my house gonna change filter again then I guess its back to the third pump fuel isn't coming up to twenty psi right now

---------- Post added at 07:16 PM ---------- Previous post was at 06:42 PM ----------

Or anyone really

Did you check the fuel sock in the tank? Filter?
How about the pressure regulator, checked or replaced?
You must be picking up some debris or have some bad wiring or grounds if it is killing pumps.


Clean the tank good while you have it out and make sure you get a new sock with the pump.

[ebourd]

Sock is clean pressure reg is new ran new wires tank is spotless guess I'm just headed back to pump

[90mustangLX]

Originally Posted by ebourd

Sock is clean pressure reg is new ran new wires tank is spotless guess I'm just headed back to pump

What's it look like on the under side of the pump with the sock off?

[ebourd]

Brand new pump same as last one

[ebourd]

Just want to thank everyone for the help