fuel pump doesn't pressureize lines?
11-09-2004, 03:54 AM
#1
Three Wheelin'
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fuel pump doesn't pressureize lines?
Is it normal for my 86.5 to not prime the pump and get some fuel in the lines? I'm almost certain this is something Andy's car (S4) did... but I don't think mine does. I've got a pressure gauge under the hood, and the ONLY time it ever registers is while the engine is cranking or the car is running. I can't recall ever hearing the fuel pump do its thing with the car just in the 'on' position.
Is it broken, or is it normal? Thanks in advance!
Is it broken, or is it normal? Thanks in advance!
11-09-2004, 05:52 AM
#2
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It's normal for the pump not to run when the iginition is on but the engine not turning.
This is a safety feature so that fuel cannot be pumped in the event of an acident when the engine is stopped, but the ignition is still switched on.
A few S4 and later ECUs give a very short fuel pump pulse when the igntion is first switched on.
Regards
This is a safety feature so that fuel cannot be pumped in the event of an acident when the engine is stopped, but the ignition is still switched on.
A few S4 and later ECUs give a very short fuel pump pulse when the igntion is first switched on.
Regards
11-09-2004, 06:29 PM
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Whereas my '87 S4 has never let the fuel pump stop, once the key switch is turned on. Gotta figure this out sometime soon! AND, why the pump, a new one to boot, makes noise, not always, and it oscillates!
11-09-2004, 06:32 PM
#4
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I can hear mine wirrr every now and then when I turn on the key, it's a new pump and tank.
11-09-2004, 06:41 PM
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Hacker-Pschorr,
My pump is quiet at first, but give it a minute or two, and the oscillation starts occurring!
New pump, filter, and strainer, with a freshly flushed tank! Now, who do I see about a test pressure guage? I CANNOT find a source for a fitting for the end of the fuel rail..... One place has one as part of an assembly, for $69!!!
My pump is quiet at first, but give it a minute or two, and the oscillation starts occurring!
New pump, filter, and strainer, with a freshly flushed tank! Now, who do I see about a test pressure guage? I CANNOT find a source for a fitting for the end of the fuel rail..... One place has one as part of an assembly, for $69!!!
11-10-2004, 08:30 AM
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wait a minute....
my car (81 euro S, short-blocked w/ low comp 02 motor) runs the fuel pump constantly, and loudly.
I asked the PO about this (i had a 914 once, which would act as described in this thread, on key turn would bring system pressure up, and then shut off...), and he told me that it's always done this.
He's had the car for a couple of years, not long.
I'm beginning to suspect that some PPO (or PO? i doubt he'd be able to find it...) wired the fuel pump for constant ON.
Is that possible? Why would someone want to do that?
;-(
my car (81 euro S, short-blocked w/ low comp 02 motor) runs the fuel pump constantly, and loudly.
I asked the PO about this (i had a 914 once, which would act as described in this thread, on key turn would bring system pressure up, and then shut off...), and he told me that it's always done this.
He's had the car for a couple of years, not long.
I'm beginning to suspect that some PPO (or PO? i doubt he'd be able to find it...) wired the fuel pump for constant ON.
Is that possible? Why would someone want to do that?
;-(
