tracke30m3

I've done a search and from what I've gathered you remove the DME/fuel pump relay and jump terminal #30 to terminals #87 and #87b.

I didn't hear a whirring sound, just a soft clunk and then nothing else. When I unplug the terminals and plug it in again all I get is the soft clunk once more.

Am I supposed to hear a continuos whirring or buzzing sound?

My search also came up with a suggestion to tap the black/green wire in the front trunk that leads to the fuel pump to 12V+ to see if the pump runs but the problem is I can't locate the said wire.

Does anyone have a more detailed description or maybe a picture?

Thanks.

NC TRACKRAT

I believe that if you jumpered the fuel pump relay after just driving the car, you won't hear any whirring because the system is already pressurized. Test when the car is cold and you should hear it whir until the pressure comes up.

IXLR8

Doesn't the pump run all the time? If not, where is the pressure sensor telling it to turn on again?

On some cars that have an fuel accumulator, the pump will go on and off as necessary.

Paul902

I believe NC Trackrat is correct. If you turn the key to ON after the car has been sitting for a while, the pump will run for a couple seconds. Immediate subsequent turning of the key to OFF, then ON, will not make the pump run for the several seconds again.

With the car running, the pump should run continually, as Alex suggests.

OP, are you trying to test if the fuel pump runs at all, or if it is pumping the correct volume per unit time? That test is usually done on pumps by pumping fuel from the tank for a specified time into a container, and measuring the volume that was pumped. I don't know the specifics for the 993, but it is likely in the repair manual.

IXLR8

Three tests: volume/flow, pressure, leak.

• Volume/flow test: minimum 850 cc in 30 seconds.
• Pressure test: 3.8 +/- 0.2 bar with engine off; 3.3 +/- 0.2 bar with engine at idle.
• Leak test: minimum 3.0 bar after 20 minutes.

tracke30m3

Thanks for the inputs, I'm trying to see if the pump runs at all.

The car has been out of commission for the past 6 months, cranks but won't start. It's not the DME relay since I've tried replacing it. I get spark at the spark plugs so I'm thinking the problem must be fuel related though I think I smell fuel at the exhaust after a few cranks, but could be my mind playing tricks.

Initially thought it could be the flywheel sensor but since I get spark I've ruled that out. Will a defective or improperly gapped crank sensor still get spark at the plugs?

When I tried the relay jumper yesterday it has already been about a month since I last tried to start the car so I doubt the fuel system still has pressure.

Paul902

There is a thread here discussing location of the fuel pump. I would check to see if you have voltage at the pump while cranking.

JB 911

No idea, but if you change the title of the thread to something along the lines of car sits ..cranks.. won't start I bet you get more suggestions.

IXLR8

The fuel pump is under the cover held in place by about eight M6 fasteners...

tracke30m3

I did a few weeks ago, didn't got too many replies.

tracke30m3

Thanks.

Is that your car? It's CLEAN, you could eat off of the bottom.

Paul902

Yeah, it is hard to say if I am more jealous of the cleanliness or of the lift!

IXLR8

Its a toy, but you ought to see my motorcycles. They're cleaner and have actually been places.

Anyway, bridging the relay socket should keep the pump going...for at least 30 seconds. Otherwise how could you do a fuel delivery test.

You have a PM coming.