idahoporsche

hi guys

looking for some help.. trying to get my 79 running.. there is no power to the fuel pump .. i have jumped the relay ... tried a new relay and replaced the ignition switch...

the car will run if i jump a wire directly from the battery to the fuel pump..

anybody have any ideas of what might be wrong??

thanks for your help
Russ

AirtekHVAC

Possibly there is a problem with the wires on the back of the CE panel, they are known for the connectors to pop back out of the socket. There is also some chance of bad wires and connections on the back of the CE.

AirtekHVAC

Ignition switch could also be culprit.

Socal_Tom

Do you have 12+v everywhere else you are supposed to?

If so sure sounds like a problem with the power comes into the Central Electric (CE) panel.

Edit - what led you to replace the ignition switch in the first place?

idahoporsche

replacing the ignition switch was a suggestion from someone here,, it has been a couple of years since i have played with this car, i'm just now getting back to it

i will check the connectors and the wires at the CE panel.. also today i notice that while cranking the fuel pump relay clicks continuously


Russ

Socal_Tom

Don't think it should be clicking continuously. Good discussion here;

http://forums.pelicanparts.com/porsc...ump-relay.html

Jørn

Perhaps a stupid question, but have you measured the voltage at top of the fuse, and at the bottom, i.e. the voltage drop over the fuse? I have experienced corrotion build up on the fuse causing voltage drop to big for the pump to run.

soontobered84

Replace the relay. You can also remove the relay and install a jumper to remove the relay as a possible culprit. Just remember to remove the jumper when you are done testing to avoid filling your cylinders with liquid fuel.

idahoporsche

ok
so i have already tried 2 new relays

today i checked all the connection on the rearof the CE panel...

cleaned all the ground wire/connections above the CE panel

checked for voltage at relay connection.. top connection has good voltage,,, lower connection has flashing power while cranking,,

so i assume that is why the relay clicks continuously like its following ignition spark

so what to check next ???

thanks for everyones input

Russ

soontobered84

Remove the relay and install the jumper: terminal 30 to 87. Does the fuel pump run? Does the car start?

Let us know.

Jørn

I agree with previous poster to try to remove the relay and jump 30 to 87 on the panel. However I believe you have stated that you have tried that.

Just some info in case you do not have the current flow diagram: 31 (big terminal) shall have ground, 31 (tiny terminal, think they are called a and b) comes from igniton transistor unit and tells the relay that the distributor is turning and hence engine is crancking or running (might be pulsed signal, not sure...), 15 shall have 12V when igniton is switched on. This is the voltages needed for the relay to activate the solonoid and hence close the switch which and cause current to flow from terminal 30 to 87 (if fuse is ok, you should have 12v at term 30 at all times).

Final solution if all else fails is to disconnect battery and start measuring the ciricut for continuity all the way from battery through ignition switch and back to fuel pump, just follow the current flow diagram.

Callum_GT

I had a similar issue where I was only getting 9v to the pump, pump wasn't turning and getting hot! I had an intermittent connection in the connector behind the rear quater panel, quick clean up and all good now

idahoporsche

i have a new fuel pump coming,,once it's here i will try jumping the relay again and keep you posted,,


thanks
Russ

idahoporsche

ok so

new pump will not run by jumping the relay terminals..

car will run for a couple seconds ::if i spray carb cleaner into air intake ....

if i,, jump the pump directly from the battery,, it still wont run..all i get is air by loosening the line at the fuel filter

SO 2 questions

will the pump in the tank failing cause it to not run... ( it did run a couple years ago by jumping the pump to the battery )??

any ideas why the power wont go back there from cranking the car...??

UGH !!

Russ