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Author Topic: fuel pump problem  (Read 2763 times)

SKDSUP

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fuel pump problem
« on: April 12, 2014, 03:23:18 PM »
Guys.

car has been sitting outside not started in 3 weeks, there was moisture in the engine bay which I thought may be a ignition problem.

but my fuel pump is not priming, I have pulled the fuel line off my regulator and no fuel is being pumped through.

I have checked fuses etc


does the pump need a higher voltage to run? Like 13v plus? My battery was reading 12.5v.

Hope yoh can help, I have drift school in a month!

Thanks

mark
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gtsr

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« Reply #1 on: April 12, 2014, 05:02:17 PM »
Sounds like the battery is stuffed, change it.

A battery when stuffed can be around 12-12.5 volts when starting the engine. The dash should beep if the battery voltage is too low. That's if someone hasn't removed the beeper.

Also pull the boot light bulb, as on Skylines it's known to drain the battery quicker (common problem).

Stock is around 10-12volts to fuel pump.

Hardwiring the fuel pump gives it 13.5 volts+. Most aftermarket fuel pumps are tested at 13.5volts to get the lph they are rated to.

Can buy a fuel pump hardwire kit (Tomei, Deatschwerks, etc).
« Last Edit: April 12, 2014, 05:03:40 PM by gtsr »

fast4motion

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fuel pump problem
« Reply #2 on: April 12, 2014, 06:04:31 PM »
Quote from: gtsr;625488
Sounds like the battery is stuffed, change it.


12.5V is quite normal for a good battery. And I'm assuming the engine cranked over when you tried starting it, which would confirm it's not a battery issue.

I'd start by checking the fuel pump relay, and checking for voltage/ground at the fuel pump.

SKDSUP

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fuel pump problem
« Reply #3 on: April 12, 2014, 08:00:55 PM »
Quote from: fast4motion;625491
12.5V is quite normal for a good battery. And I'm assuming the engine cranked over when you tried starting it, which would confirm it's not a battery issue.

I'd start by checking the fuel pump relay, and checking for voltage/ground at the fuel pump.


Correct, was cranking over and not firing.

I tried swapping a relay with my electric fan relay which does work, no luck though.
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gtsr

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« Reply #4 on: April 12, 2014, 09:24:14 PM »
Quote from: fast4motion;625491
12.5V is quite normal for a good battery. And I'm assuming the engine cranked over when you tried starting it, which would confirm it's not a battery issue.

At the battery???

I had a older battery down to 12-12.5 volts and it wouldn't start engine, but cranked engine over. Replaced battery, engine started with no problems.

Sitting for 3 weeks is probably long enough to drain a battery.

Sometimes need a battery booster to get it started.

Edit: But you are correct, fuel pump not priming points to the real problem.

Checked fuel pump fuse in engine bay fuse box????
« Last Edit: April 12, 2014, 09:48:30 PM by gtsr »

mŮk

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fuel pump problem
« Reply #5 on: April 12, 2014, 11:45:37 PM »
Quote from: gtsr;625497
At the battery???


12.5v at the battery when it's sitting is normal. A car should be able to sit round for 3 weeks with a good battery and start unless it's got higher than normal current draw. Do what fast4motion says, sometimes when the pump is dodgy you can give the tank a whack and it will get it going again for a short time
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Pandaemonaeon

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« Reply #6 on: April 13, 2014, 10:49:32 AM »
The factory fuel pump runs at 5V when it's in low flow mode, the battery voltage is not the issue.
Jump in the boot and see if you can actually hear the pump priming when you turn the ignition to on.
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SKDSUP

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fuel pump problem
« Reply #7 on: April 13, 2014, 02:56:01 PM »
Got a result.

I took my battery back to the supplier, who charged it over night. (Was a flash battery supposedly)

Put back in car, and pump primed up no issues at all.

looks to be a low voltage issue with battery.

thanks for help and tips.
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Pandaemonaeon

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« Reply #8 on: April 13, 2014, 05:37:48 PM »
That would have been the whole ECCS system not working if charging the battery has fixed it. In theory you wouldn't have had spark either.
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SKDSUP

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« Reply #9 on: April 13, 2014, 08:57:56 PM »
Quote from: Pandaemonaeon;625512
That would have been the whole ECCS system not working if charging the battery has fixed it. In theory you wouldn't have had spark either.


Ahhhh! Interesting!  Thanks man
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gtsr

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« Reply #10 on: April 14, 2014, 11:34:25 AM »
Good to hear. :)