Audi S4 fuel pump issues

Newbie Joined: Jul 07, 2014 Posts: 6

Hello!
I have a 1992 Audi S4. The fuel pump went out so i replaced it, it worked fine for about a week. Now the fuel pump wont turn on while plugged in. I tested if it is getting the right amount of voltage, with just the key on it rests at .02v when i turn the key over it only goes to .05v. I have no idea what would cause this and haven't been able to find anything online.

Please help!

Posted: Wed Jul 09, 2014 8:15 pm

Check fuel pump fuse first. Don't know which one it is but probably shown on the fusebox lid.

If that's ok then I suggest checking the fuel pump relay. Once identified it should be possible to remove it from it's socket and bridge the power pins in the socket to see if that makes the pump run.

Cheers

Nick

Newbie Joined: Jul 07, 2014 Posts: 6

The fuse is good, so ill have to look into the relay. Thank you!

Bandwidth Buster Joined: Aug 12, 2006 Posts: 803

furthest right relay under the trim under steering wheel if you are having trouble finding it

Newbie Joined: Jul 07, 2014 Posts: 6

So, i checked at the relay is good but i replaced it just in case. it still does not run, although i checked if all the wires were giving the correct voltage output and the one running from the ignition switch to the relay is not geting the correct voltage, do you have any ideas on what could cause this?

Bandwidth Buster Joined: Aug 12, 2006 Posts: 803

Ignition switch buggered?

Newbie Joined: Jul 07, 2014 Posts: 6

It sends less than 12v then when you try to turn it over it drops to 8-10v so it isnt enough to get the relay to do its thing. how would i know for sure if it is that?

Bandwidth Buster Joined: Aug 12, 2006 Posts: 803

take the connector off the back of the switch and either bridge which ever pins you need to or just give the fuel pump relay wire direct voltage then test at the pump again.

Newbie Joined: Jul 07, 2014 Posts: 6

Thanks, just ordered a new ignition switch. hopefully this will fix it.

Newbie Joined: Jul 07, 2014 Posts: 6

New ignition switch in, the volts going to the relay are better and dont drop now. It still doesnt send enough to the fuel pump, we tryed to jump it and the fuel pump worked but it was not starting... any more ideas?