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Jamesmay924
Joined: 16 Jan 2012
Posts: 13
Location: Christchurch New Zealand
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 Posted: Sat Feb 11, 2012 9:33 pm Post subject: Heeeelp... Fuel pump relay |
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Thanks in advance...
82' 924 N/A, i think the fuel pump relay is on the blink, i would replace it with an easy to source 30A bugger, but according to the Haynes manual there is 2 extra connections and a "solid state" electronic device inside it...
does anyone know what these extra connections actually do?.
To my mind... there should be the 2 coil connections and 2 high current/ switched connections, what on earth would the other 2 do???
i would just get a like for like replacement, but this is NZ and the word Porsche loosly translate to rip me off for any parts...
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1982 924 N/A 5sp (UK import)
2004 Audi A6 Quattro Avante |
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Harm
Joined: 02 Apr 2009
Posts: 1378
Location: Holland
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| Posted: Sat Feb 11, 2012 10:24 pm Post subject: Re: Heeeelp... Fuel pump relay |
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Short answer:
The Fuel Pump Relay is designed to cut power
to the fuel pumps if the engine isn't running independently;
A build in safety measure in the event of an accident.
The Fuel Pump Relay starts the pumps at power-on,
then ‘waits’ for the tach signal (coil (without running the starter)).
When it's not there in a few seconds/turns,
it shuts the pumps off.
Jumper circuit 30 and 87 the pump should run all the time. …Not my advise!
HTH
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Porsche 924 NA 1982 LY7A/A3A3 _ Greater driving pleasure never harmed anyone. |
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ptheskil
Joined: 03 Aug 2004
Posts: 128
Location: Essex, UK
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| Posted: Sun Feb 12, 2012 3:58 am Post subject: |
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I've asked this question before so apologies for asking it again BUT...
I have never known a K-jetronic system run the fuel pump(s) for a few seconds at ignition on before crank. For the pump(s) to run the engine needs to be turning over (either running or cranking). Other than that the pump(s) do not run.
Here's another post stating that the pump(s) run for a few seconds at ignition on. Harm, are you sure about that? Do I have dodgy relays which for some reason don't prime the pump(s)? Is it the difference between OE and aftermarket? Anybody know?
Thanks.
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1981 931 series2 Euro spec |
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Sun Feb 12, 2012 5:07 am Post subject: |
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Mine is a factory unit that briefly pressurizes the system on a timer when the ignition is first turned on. As a result, the car fires with a bump of the starter.
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Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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Jamesmay924
Joined: 16 Jan 2012
Posts: 13
Location: Christchurch New Zealand
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| Posted: Sun Feb 12, 2012 6:48 pm Post subject: Re: Heeeelp... Fuel pump relay |
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| Harm wrote: | Short answer:
The Fuel Pump Relay is designed to cut power
to the fuel pumps if the engine isn't running independently;
A build in safety measure in the event of an accident.
The Fuel Pump Relay starts the pumps at power-on,
then ‘waits’ for the tach signal (coil (without running the starter)).
When it's not there in a few seconds/turns,
it shuts the pumps off.
Jumper circuit 30 and 87 the pump should run all the time. …Not my advise!
HTH |
Thanks
I suspected something like this....
Mine definately pressurises when initially turned to on (recognise the sound from old racecars...)
Is there a replacement version available from bosche etc?.... i would prefer to get a new one rather than another second hand one....
Thanks again 924'ers
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1982 924 N/A 5sp (UK import)
2004 Audi A6 Quattro Avante |
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Harm
Joined: 02 Apr 2009
Posts: 1378
Location: Holland
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| Posted: Mon Feb 13, 2012 2:14 am Post subject: Re: Heeeelp... Fuel pump relay |
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| ptheskil wrote: | I've asked this question before so apologies for asking it again BUT...
I have never known a K-jetronic system run the fuel pump(s) for a few seconds at ignition on before crank. For the pump(s) to run the engine needs to be turning over (either running or cranking). Other than that the pump(s) do not run.
Here's another post stating that the pump(s) run for a few seconds at ignition on. Harm, are you sure about that? Do I have dodgy relays which for some reason don't prime the pump(s)? Is it the difference between OE and aftermarket? Anybody know?
Thanks. |
Sorry to hear that ptheskil.
Currently both fuel pumps and the tank are out (fuel leak
(and restoring the rear suspension, and engine, and front wings and-and…)) 
So i'm unable to send you any digital proof through Youtube of the car starting.
Second note:
During the starting procedure the pumps are activated only for a
short amount of time; about 6 or 10 seconds if I remember correct.
After that I'm mostly abusing my battery…
I have to return the key, wait one sec, and start the starter procedure over again.
Do others recognize this start pattern?
I'll see if I can dig up my Fuel Pump Relay part number.
Regards, Harm.
Edit01: #433906059
Last edited by Harm on Tue Feb 14, 2012 5:21 am; edited 1 time in total |
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staticsan
Joined: 19 Jan 2009
Posts: 450
Location: Sydney, Australia
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| Posted: Mon Feb 13, 2012 12:15 pm Post subject: |
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New relays are easy to get. Shop around, though, if you want to try to save. A genuine part from Audi cost me AU$140, but I hear you can buy one off one of the Porsche parts websites for much less than that.
Wade. |
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924aussie
Joined: 02 Feb 2006
Posts: 1009
Location: Chinchilla Queensland Australia
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| Posted: Mon Feb 13, 2012 12:18 pm Post subject: |
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Have you bypassed the relay to see if the pumps work ?
If not we can provide the link to do this, its also in the Haynes manual
Alan
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green 924 .. 1980 rego 924PSH
1998 Mopar Neon ... sick
2003 Challenger / Montery 4WD
1995 Hyundai Scoupe ... sold
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BIG BLOODY MOTORHOME 300zx Sold
1980 Fire truck Sold |
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932kiwi
Joined: 06 Dec 2009
Posts: 44
Location: Wellington N.Z
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| Posted: Mon Feb 13, 2012 2:33 pm Post subject: |
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| I've just replaced mine 2 weeks ago used part number 433906059 and got it from pelican parts. |
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