efi fuel pump problem?

[mr.maestro]

been having fuel starvation problems with my efi.
when you switch the ignition on, pump runs for a few seconds to build pressure, then stops......correct.
therefore if you dis-connect the inlet pipe at the filter (to pump tank out), the pump should keep running, yes?
anyway, with the pipe off, pump ran for a few seconds and stopped.
have i got a problem somewhere else or am i missing something?
i've run a wire direct from the pump, via a switch, direct to the battery and the car runs alot better. i'm wondering if there is a fault with the fuel pressure switch? any way of testing it?

[Jeff Turbo]

been having fuel starvation problems with my efi.
when you switch the ignition on, pump runs for a few seconds to build pressure, then stops......correct.
therefore if you dis-connect the inlet pipe at the filter (to pump tank out), the pump should keep running, yes?
anyway, with the pipe off, pump ran for a few seconds and stopped.
have i got a problem somewhere else or am i missing something?
i've run a wire direct from the pump, via a switch, direct to the battery and the car runs alot better. i'm wondering if there is a fault with the fuel pressure switch? any way of testing it?

Possible relay failure

[G Force]

been having fuel starvation problems with my efi.
when you switch the ignition on, pump runs for a few seconds to build pressure, then stops......correct.?

Hi maestro man.

Yes that is what should happen.

therefore if you dis-connect the inlet pipe at the filter (to pump tank out), the pump should keep running, yes?. Anyway, with the pipe off, pump ran for a few seconds and stopped.
have i got a problem somewhere else or am i missing something??

No. The pump only runs for 2 seconds to prime the system, which is what you witnessed. The pump doesn't run until a certain pressure is achieved in the rail & then stop. Only the regulator controls fuel pressure, the sensor in the rail is a temperature switch on manual transmission cars & a temp sensor on automatic transmission cars.

i've run a wire direct from the pump, via a switch, direct to the battery and the car runs alot better. i'm wondering if there is a fault with the fuel pressure switch? any way of testing it?

If you are having starvation symptoms while driving you should probably look at the Filter or pump or the fuel tank and plumbing. If the injectors are glazed the engine will run lean all the time.

Cheers, G Force

[mr.maestro]

thanks for the replies chaps, looking at the relay as filter is clean and pump is new-ish

[G Force]

thanks for the replies chaps, looking at the relay as filter is clean and pump is new-ish

Hi

If the car starts and runs normally without having to run a 12v feed wire directly to the fuel pump, then there can't really be a problem with the fuel pump relay.

Cheers, G Force

[mr.maestro]

the exact problem i had was;
car started and ran fine for about 6 miles, where it stood ticking over for 5 minutes then ran very rough, displaying symptoms of fuel starvation, for another 5/6 miles then seemed to run ok to my first destination 8 miles further on.switched it off then re-started 35 minutes later, ran rough again for 4/5 miles then ok for another 40. stopped again half an hour, ran rough 4/5 miles, then ok home, 13 miles. i have had trouble with the car a few years ago with muck in the tank bunging the filter up, but regular filter changes and a new pump seemed to sort that.

[mr.maestro]

just to update this thread, finally sorted the problem! it turned out there was a broken wire in the plug on the airflow meter giving an intermittent signal from the airflow meter to the ecu, hence the fuel starvation like symptoms. removed plug, replaced with spade connectors, job sorted. car runs better than ever!!

[ian drew]

Well done that man. That's the sort of problem I dread, months to find, minutes to fix.

Ian