Is there two fuel pump relays 1979 911?

[Dark Age 53]

I'm asking for my cousin who owns the car, found one under the front hood but was wondering if there's a second relay. The reason I ask is he has a no start, I hear/feel a slight click from the one under the front hood but the fuel pump doesn't make any noise. I hot wired the fuel pump and I can hear the fuel pump, disconnect the hot wire and nothing. Thanks.

[rattlsnak]

No, just one relay. Are you checking with just key on, or when cranking engine?

[Sboxin]

DME relay under the driver's seat - - NOT - - . . . perhaps . . . JMHO of course . . .

Edit: Ooops . . . get our car confused because several different years of stuff . . .

Regards,

[rattlsnak]

^^ SC's don't have DME relays..

[Dark Age 53]

Originally Posted by rattlsnak

No, just one relay. Are you checking with just key on, or when cranking engine?

Just with the key in the on position, thanks.

[boyt911sc]

Originally Posted by Dark Age 53

I'm asking for my cousin who owns the car, found one under the front hood but was wondering if there's a second relay. The reason I ask is he has a no start, I hear/feel a slight click from the one under the front hood but the fuel pump doesn't make any noise. I hot wired the fuel pump and I can hear the fuel pump, disconnect the hot wire and nothing. Thanks.

Remove the FP relay and bench test it. Test also the FP relay socket for any electrical anomaly. Search for DKLever48's thread about FP relay testing. Everything you need to know about FP relay test were discussed in that thread.

Tony

[Flat6pac]

If you remove the relay and jump terminal 30 and 87a that will turn on the pump if the pump is good.
Bruce

[john walker's workshop]

Cut-off relay by the left hood hinge. Unplug it.

[rattlsnak]

Originally Posted by Dark Age 53

Just with the key in the on position, thanks.

Pump will not normally run with key on only unless you are cranking engine (or its running).

[Dark Age 53]

Originally Posted by boyt911sc

Remove the FP relay and bench test it. Test also the FP relay socket for any electrical anomaly. Search for DKLever48's thread about FP relay testing. Everything you need to know about FP relay test were discussed in that thread.

Tony

Going back Thursday to check it out.

Originally Posted by Flat6pac

If you remove the relay and jump terminal 30 and 87a that will turn on the pump if the pump is good.
Bruce

I thought I read to use pin 87 and 30, can you use pin 87A instead of 87?

Originally Posted by john walker's workshop

Cut-off relay by the left hood hinge. Unplug it.

Are you referring to the red fuel pump relay?

Originally Posted by rattlsnak

Pump will not normally run with key on only unless you are cranking engine (or its running).

When you first turn the key to the on position you should hear the pump priming the fuel system, am I correct in my thinking?

Thanks for all the help.

[john walker's workshop]

Cut-off relay cuts off fuel pump function on over-rev on early SCs. Find the left hood hinge pivot point and unplug the white plug at the bottom of the square black relay and see if that helps.

[Dark Age 53]

Originally Posted by john walker's workshop

Cut-off relay cuts off fuel pump function on over-rev on early SCs. Find the left hood hinge pivot point and unplug the white plug at the bottom of the square black relay and see if that helps.

Thank you.

[Dark Age 53]

We accomplished nothing today. Removed the fuel pump relay and jumped 30, 87a, I heard a click or something for a split second when the was key turned on ( not to the start position ), yesterday when I ran a wire from the positive side of the battery to the positive side of the fuel pump I could hear the fuel pump until I disconnected the hot wire.

I tried to find the cut-off relay but couldn't, we'll try again Sunday to see if we can't find the problem....just about ready to throw in the towel.

[pors1968]

Did you check if you with test light if fuse is ok and voltage pin 30 .

[Dark Age 53]

Originally Posted by pors1968

Did you check if you with test light if fuse is ok and voltage pin 30 .

Checked number 6 fuse ( fuel pump fuse ) and test light showed it was o.k, didn't check voltage in pin 30.....should it show 12 volts? Thanks

[pors1968]

Try to clean wire on both side of fuse .Fuse might be ok but these wire get hot and contact are not good enought.

[boyt911sc]

Originally Posted by Dark Age 53

We accomplished nothing today. Removed the fuel pump relay and jumped 30, 87a, I heard a click or something for a split second when the was key turned on ( not to the start position ), yesterday when I ran a wire from the positive side of the battery to the positive side of the fuel pump I could hear the fuel pump until I disconnected the hot wire.

I tried to find the cut-off relay but couldn't, we'll try again Sunday to see if we can't find the problem....just about ready to throw in the towel.

Dark Age,

Did you get a chance to read DKLever48's post about FP relations test? That is the basic test you need to understand how and what to expect. Otherwise, you will be wasting your time looking for something you have no clue. It would take a few minutes of reading to guide what and where to do the tests. Keep us posted.

Tony

[timmy2]

Did you try the really simple test of turning ignition to run and lifting the air metering plate in the airbox to see if the pump runs? Injectors will squeal if it does, and you should stop when you hear them do that.

[Dark Age 53]

Originally Posted by boyt911sc

Dark Age,

Did you get a chance to read DKLever48's post about FP relations test? That is the basic test you need to understand how and what to expect. Otherwise, you will be wasting your time looking for something you have no clue. It would take a few minutes of reading to guide what and where to do the tests. Keep us posted.

Tony

I need to re-read it again, one thing in the thread said when he hot wired to the fuel pump the car would run. In our case I could hear the pump but the car wouldn't start, we sprayed some starting fluid and it started and it started but stopped once the starting fluid ran out......also, the starter seemed to stay engaged.

Originally Posted by timmy2

Did you try the really simple test of turning ignition to run and lifting the air metering plate in the airbox to see if the pump runs? Injectors will squeal if it does, and you should stop when you hear them do that.

Yes, nothing happened.

[boyt911sc]

Dark Age,

You are totally missing the point of my suggestion about DKLever48's post. The objective of reading the post is for you to understand how each terminals are tested. And relate them to your case. So far, I think you are still not aware which terminals are NC (normally closed) and NO (normally open) for the FP relay. It may sound complicated but they are not. It would need less than a minute to evaluate or test the FP relay socket and another minute to test the FP relay.

If the FP relay and socket passed the tests, then you could move on and look for other possible culprits. At this stage, focus on the FP relay/socket/wiring and share your results. Do you understand how terminals 87a, 87, 86, 85, and 30 work with the ignition switch @ ON/OFF positions? If you do, that is great. If you don't, that is another problem for your troubleshooting. Keep us posted. Thanks.

Tony