testing fuel pump and pressure 1985.
Thread Starter
Racer
Joined: Sep 2015
Posts: 261
Likes: 24
From: Israel
testing fuel pump and pressure 1985.
Hi,
When I apply 12V from the battery to port "G" in the ALDL, I can hear my pump runs as long there is 12V to G and getting about 30psi.
I normal condition, the pressure should stay when I disconnect the 12V to G? In my case it drops to zero. There is no fuel in the hose of the FPR. No, fuel when I press the schrader valve.
Yes,I have fuel in the tank.
P.S. the switch is OFF while doing the test.
Thanks.
When I apply 12V from the battery to port "G" in the ALDL, I can hear my pump runs as long there is 12V to G and getting about 30psi.
I normal condition, the pressure should stay when I disconnect the 12V to G? In my case it drops to zero. There is no fuel in the hose of the FPR. No, fuel when I press the schrader valve.
Yes,I have fuel in the tank.
P.S. the switch is OFF while doing the test.
Thanks.
Melting Slicks
Joined: Mar 2001
Posts: 2,150
Likes: 304
From: Timra, Sweden
It should drop slowly.
It could be seat in the regiuator not closing compleatly.
It could be leaking injector.
It could be check valve in the fuel pump.
Leaking injector is the only one to worry about.
It could be seat in the regiuator not closing compleatly.
It could be leaking injector.
It could be check valve in the fuel pump.
Leaking injector is the only one to worry about.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 413
From: WV
If it's not the FPR, then the gas has to either be leaking into a cylinder from an injector, or running back into the tank because of the fuel pump... There is no where else for it to go and not be seen on the ground. If I'm not mistaken you should be able to turn on the key to energize the pump, then pinch off the supply line, then turn off the key... If the system holds pressure with the line pinched off , then loses pressure when unpinched ,then it's most likely the pump is bad... WW
Last edited by WW7; Mar 1, 2020 at 05:06 PM.
Thread Starter
Racer
Joined: Sep 2015
Posts: 261
Likes: 24
From: Israel
Hi.
I opened the fuel tank cap and made a voice record with the cell phone. I can heard the pump working while G got 12v. I couldn’t hear other thing besides the pump itself. I already ordered a new fuel pump. The one I have was bought from racetronix about 10k miles ago. Walbro 160/180 lph as far as I remember. My next step is to replace it with the new one.
We use 95RON gasoline. I assume its 91/93 in the States.
I opened the fuel tank cap and made a voice record with the cell phone. I can heard the pump working while G got 12v. I couldn’t hear other thing besides the pump itself. I already ordered a new fuel pump. The one I have was bought from racetronix about 10k miles ago. Walbro 160/180 lph as far as I remember. My next step is to replace it with the new one.
We use 95RON gasoline. I assume its 91/93 in the States.
Melting Slicks
Joined: Mar 2001
Posts: 2,150
Likes: 304
From: Timra, Sweden
Usually a pump does not fail in a way that cause it to loose pressure/flow. If they do it is usually because of a clogged filter sock or a leak in the fuel tank ( bad hose).
I would check that hose and add hose clamps and check the filter sock.
When the pump is out you can test it on the bench, both flow and pressure.
I would check that hose and add hose clamps and check the filter sock.
When the pump is out you can test it on the bench, both flow and pressure.
Last edited by JoBy; Mar 2, 2020 at 09:39 AM.
