924Board.org

Dan · Joined: 27 Apr 2008 Posts: 24 Location: Great Yarmouth, UK

Is that the timing mark on the distributor?

Also just replaced fuel pump relay, I cant turn the engine over (Cams off) but when the ignition is put to on position, I get voltage at the pump for about a second, not long enough to get a good reading.
I understand this is to pressure up but I don't hear the pump run (the pump works wired direct)

How long is normal when initially energised should this relay stay on to pressurise, as my replacement has four spades , and the old one (smells burnt) has an extra miniture spade, so I'm not sure its the right one?

Will the pump run if already at pressure?

Is there any way to test without turning the motor over?
_________________
Dan

1979/924 N/A
Street Racer KTA508V
©2008

Paul · Posted: Mon Apr 28, 2008 1:40 am Post subject:

Yes, the rotor should point at that mark when #1 is at TDC. This sets the timing near TDC, then use a timing light.

Jumper the fuel pump relay to see if the pump and wiring are OK.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Ozzie · Posted: Mon Apr 28, 2008 7:29 am Post subject:

On later cars the pump only runs when cranking or engine is running.
Not sure when it changed from a switch on the CIS.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

The fuel pump relay behaviour that you describe is correct for the later type of relay. Don't be concerned that you can't hear the pump during that first second.

The miniature spade gets a signal from the coil when the engine is running. If the engine stalls, the relay cuts power to the pump. It's a safety feature in case of an accident, etc.

Earlier cars only had a four-terminal fuel pump relay. The cut out feature was a switch on the air meter. I think by 1979 all cars had the later relay, but I can't be sure...
_________________
1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org