Other 70 Problem: Fuel Pump Fuse Blowing Constantly

[RWD]

A couple of weeks ago I was coming back from holiday, I parked up for 5 minutes and when I went to set off again the car died after approx 20 seconds.

I tried starting it and the car just kept turning over. I check the fuses and no.33 for the fuel pump had blown. I replaced it and the car ran fine and I made it home.

Later the same day I went out to the car to take some relatives home, it died straight away. I checked the fuse, it had blown again. I replaced it and as soon as I turned the key to start it, the fuse blew again. Obviously it has some underlying problem!

I didn't have time to check it out, and fortunately have access to another car so can get around.

I called a car technician friend who came and had a look, check the fuses and they constantly blow as soon as you turn the ignition. He diagnosed a dodgy pump.

I replaced the pump tonight after waiting for over a week for the correct one to arrive, checked and double checked all connections, replaced the fuse, turned the key and *pop*, the flippin' fuse blew again.

As you can imagine, I am somewhat dischuffed at forking out for a brand new pump and for it not to cure the fault.

I should be picking up a VIDA DICE unit tomorrow so I can check codes etc.

Has anyone else had any similar problems and if so, how did you solve it?
I have looked for a fuel pump relay but cannot find one, which leads me to think that there may be a control unit somewhere which my be faulty...

Thanks,
RWD

The car is an 04 model V70R Manual

[Simon Jones]

Do you tend to drive around with the fuel gauge on nearly empty most of the time? If so, it causes the pump to run hot which can shorten their lifespan and increase current consumption.

If its a brand new pump then you wouldn't expect it to suffer any problems that a unit that has been overheating for a while could have. What the rating on the fuse you are using? From the online manual, it looks to be 15a (blue).

[4candles]

Originally Posted by RWD

A couple of weeks ago I was coming back from holiday, I parked up for 5 minutes and when I went to set off again the car died after approx 20 seconds.

I tried starting it and the car just kept turning over. I check the fuses and no.33 for the fuel pump had blown. I replaced it and the car ran fine and I made it home.

Later the same day I went out to the car to take some relatives home, it died straight away. I checked the fuse, it had blown again. I replaced it and as soon as I turned the key to start it, the fuse blew again. Obviously it has some underlying problem!

I didn't have time to check it out, and fortunately have access to another car so can get around.

I called a car technician friend who came and had a look, check the fuses and they constantly blow as soon as you turn the ignition. He diagnosed a dodgy pump.

I replaced the pump tonight after waiting for over a week for the correct one to arrive, checked and double checked all connections, replaced the fuse, turned the key and *pop*, the flippin' fuse blew again.

As you can imagine, I am somewhat dischuffed at forking out for a brand new pump and for it not to cure the fault.

I should be picking up a VIDA DICE unit tomorrow so I can check codes etc.

Has anyone else had any similar problems and if so, how did you solve it?
I have looked for a fuel pump relay but cannot find one, which leads me to think that there may be a control unit somewhere which my be faulty...

Thanks,
RWD

Buy cheap pay dear.....

[RWD]

Originally Posted by Simon Jones

Do you tend to drive around with the fuel gauge on nearly empty most of the time? If so, it causes the pump to run hot which can shorten their lifespan and increase current consumption.

If its a brand new pump then you wouldn't expect it to suffer any problems that a unit that has been overheating for a while could have. What the rating on the fuse you are using?

I normally top up once it gets to around a quarter of a tank, it is currently at about a quarter full according to the gauge now.

When I swapped the pump tonight I noticed that the left hand side of the tank with the sender in is at a higher level than the pump side.

I replaced the pump with a brand new Volvo unit.

I have been replacing the fuse with the correct rating which is 15a as you said.

[cheshired5]

Have you traced the wiring for a short or bad earth?

[RWD]

Originally Posted by 4candles

Buy cheap pay dear.....

Thanks for the helpful comment smarty pants.

The car has been to a main dealer for most of its life, only now and again being serviced by a good local indy garage. I know the previous owner spared no expense as I have reams of paperwork. The chap I bought it off is a fellow Volvo nut and I've known him for a while - he's not the type to rip me off.

No fuel pump issues were evident when I bought it, and its not something you can normally check for on a test drive.

To be fair, given the price I paid I don't mind having to fix the odd issue here and there.

[RWD]

Originally Posted by cheshired5

Have you traced the wiring for a short or bad earth?

No, I haven't checked for a bad earth. I shall check that next. I did check the wiring to the pump and sender when I swapped the pump but couldn't see any evidence of a short or breakage in the wiring.

[tdi]

If you look inside the o/s rear wheel there is a black box that is the pump control module. There are known to suffer water ingress hence the later one the module was repositioned inside the car. Check for any bad connections. It may have thrown a fault code as well .

[RWD]

Oh, thanks. I shall check that tonight, I'll clean all the contacts etc. Do these have to be programmed in if I end uploading to replace it ?

[tdi]

There is just one connector on the top. No they shouldn't need to be programmed. The module is just above the fuel filter. Probably no harm in changing that as well.