DME jumper confusion : fuel pump sound

[Bukowski]

Clark's Garage has this excellent tutorial on jumping the DME to start the car when the DME goes bad:

http://www.clarks-garage.com/pdf-manual/fuel-05.pdf

I have experienced the magic first hand, in fact.

In particular, the tutorial claims that, if terminals 87 and 87b are connected, the fuel pump can be heard after terminal 30 is connected (so the total terminals connected is 30, 87, and 87b).

Then there is a picture of the terminals jumper end on a DME - is this the alternate connection using terminal 86 instead of 30? My DME seems to be missing the numbers (will look into it).

I just want to run the fuel pump but not start the car. My DME looks like the one in the picture, but I do not hear the pump. I'd also like to merely connect the DME terminals as shown.

UPDATE: I have 30, 87 and 87b jumped on the DME using copper wire, according to the numbers on the side. Perhaps this bad DME is worse now.

[Dave Colangelo]

30 to 87b will run your fuel pump and nothing else. In any case jumping the DME relay connections will not start the car it will simply run the fuel pump and power the DME computer its self. You need to turn the key (to the start position) to get the engine to crank.

Regards
Dave

[Bukowski]

oK just 30 and 87b - perhaps I will try my good DME.

So what should I hear? Shouldn't the fuel lines and hoses feel like a pump is going?

This should be obvious, right?

[Bukowski]

... at this point I ought to say the tranny, brake master cylinder, brakes are disconnected.

[Dave Colangelo]

The pump is noisy, if you have a quiet garage you should hear a whining sound from the back of the car where the pump is. If you need conformation remove the bolt at the head of the fuel rail, put a bucket below it and jump the relay. You will see fuel pour out into the bucket. Please be careful when doing this as you have both live electricity and exposed fuel. I like to get a nice chunk of hose over the fitting and run it to a bucket on the floor so I can work it alone. The fuel system is a return style so the fuel will flow through it freely and thus if its noisy around you may not hear the pump run.


Most importantly make sure there is fuel in the tank, I once ran a pump on a dry tank (on my 911) by accident once and it made a VERY nasty noise.

Regards
Dave

[Bukowski]

The pump isn't starting. My guesses are :

1. Tranny, brake wear sensors need to be connected.

2. Fuel pump connectors not making contact

3. Pump is dead

... might need to start a new thread...

[Dave Colangelo]

GROUNDS GROUNDS GROUNDS. These cars suffer from a perpetually corroded ground issue. Pull your grounding points and clean them up.

Then the first test you should do is to pull the pump and bench test it. Just get it off the car and connect it to the battery (use an inline fuse to protect the + side).

From there take a look at the connections on the pump they may be corroded.

The sensors should have nothing to do with the pump, a relay jump will hard power the pump there is nothing else in the line.

I had a ground issue with my 924S pump. I ended up running a new chunk of wire up into the trunk and to the ground at the back of the car. It has worked flawlessly since.

Regards
Dave

[Bukowski]

The fuel level sender works

[Bukowski]

Don't want to make this a grounds thread, but where in the PET are the bolts for the wire harnesses? I can figure out the bolts that are there, but I can't find any diagram in the PET - as I read about grounds though, perhaps I'll find it.

[Dave Colangelo]

This is what you seek.



Regards
Dave

[Bukowski]

for whomever is interested:

at the fuse box in the engine compartment, fuse no. 34 : fuel pump (and oxygen senso?r sender! how can that be?!), 15 amps ; was missing. put in new fuse. put in 30-87b jumper DME. heard whirrnnnnnnnnnnn sound from the rear of the car, let go for 10 seconds. the sound decreases in frequency a little, like the battery is going out. reset to good DME, check battery is good at ~ 12 amps.

I do not know what fuse 34 was out for.

problem solved - thanks for the suggestions... BTW I did not clean any grounds yet, and the car was as described above.

[911tracker85]

regarding ground locations. I have that diagram, but never sure if I am finding all of them.

anyone know of a thread where pics of these ground locations are posted?