308QV fuel pump blowing fuse

You just never know what happens when cars sit...

If I recall correctly, a new fuel pump draws about 7-9 amps. Certainly not enough current to warm a "good" fuseholder.

Curious to see how this plans out...

Good luck,
David

You are correct David. It should be right about 9 amps. I have been blowing a 30 amp fuse so I was way off the scale... Changing the fuel filter has helped, but there is still something out there that is causing this excessive pull.

One thing is for sure though... She sounds AWESOME when she is running. I can hardly wait to get her on the road for a road test...

JL

I agree the screen in the tank could be fouled.......big filter was OK?

The fuel filter looked fine, but that was just the outside. Can't see the inside. Anyway, swapping that one out did have an impact on the fuel pump fuse. We will see how the filter in the fuel tank looks tonight.


JL

Well Jeremy???????

Is your baby alive yet? Did you try a dedicated wire from the battery (with an inline fuse just in case) to the fuel pump to check current flow? Then you would know definitely if it is a fuel pump issue, a bad connection, or other power user in the fuel pump circuit. Have you checked the voltage at the pump terminations with the pump running?

I hope you have already found the problem and you're driving it right now.

P.S. I get the 308 out of the shop tomorrow. He replaced all of the injectors.

Ok, I swaped out the fuel pump relays. This had no effect on the situation. I then ran a direct wire from the fuse to the fuel pump. This did a couple of things. First, it allowed the fuel pump to run without the key in the ignition (as it bypasses the FP relay, and second the fuse never got over 83 degrees. So it looks like there is a short somewhere in the wire going to the fuel pump.

My next step is to find which wire goes from the FP relay to the fuel pump and replace it. Sooooo, Donny, do you have that wiring diagram that was enlarged in digital format??? It would really come in handy right about now.

I would vote for a bad connection rather then a short. Is there any plug connectors between the fuse block and the fuel pump? Corrosion at the connector could cause these issues.

It's not in digital format, just analog, a.k.a paper. It's a pretty good drawing though and might fax OK. Give me a call tomorrow with your fax number, and I'll send it to you.

I don't have the diagram with me right now, but I know it's a pretty simple circuit. I think from the fuel pump relay, there are two wires. One straight to the fuel pump. The other wire goes to the connector under the oil cooler and has two more wires leaving there. One goes to the warm up regulator heater and the other one goes to the O2 sensor protection circuit. I'm sure there are other connectors somewhere in there that I have forgotten, but your probably right Paul. Wires don't gererally "go bad", unless they are damaged somehow. It's most likely a connector or some other component in the circuit that is pulling the voltage down enough to cause high current flow to the pump when it's pumping. When I look at the schematic tomorrow we can try to isolate the culprit.

P.S. Paul, I saw your car tonight. Mike said it would go on the rack next. Mine's running great!! Had a blast driving back from N.O.

Status update....

I have narrowed it down to the brown wire that comes off the bottom terminal of the fuel pump relay (See photo). This brown wire joins a bunch of other wires and makes its way down the center consol towards the engine bay.

Any idea where it goes?

I first thought it went to the fuel pump, but the wire at the fuel pump is black. Don and I will try toning out this wire tomorrow to see where it goes.

Here are some pics.


(Message edited by f512m on April 15, 2005)