Hi all,
Don't know if this is a common occurrance but I've come accross it a couple of times now on two different cars. 15 amp fuel pump fuse blows for no apparant reason resulting in obvious non-start. After replacing fuse car seems to be OK again. Don't know if this is a sign of something to worry about (fuel pump possibly wearing out?). Anyone had this before with a definitive outcome (fix) or any suggestions please.
Regards,
Derek

Had same with an earlier quite low mileage focus last year. Sometimes it would cut out and the fuse may or may not have blown. Bit the bullet and replaced the in tank pump/sender. Piggy of a job,seemed to get fuel everywhere as the tank needs to be lowered. I found the unit quite tricky to locate on its lugs.
Car has been fine since. I think the unit was about £150.
HTH Tony

Hi Tony,
Thanks for that, I'll advise customer might need new pump.
All the best,
Derek

I think your diagnosis is spot on.

I've attended two Focus's with the same fault, blowing the fuse at random.

One was blowing it on/off for 12 month's before the pump eventually failed.

I was never lucky enough to just put a fuse in, always a tow in job.

A colleague has also had Ford Ka do it.

Terry

Hi All,
There is a very useful gadget available that I find useful for this type of problem. It is a small digital ammeter with an adapter on the end to fit directly into blade fuse holders. I have seen them on ebay for £12.99 and even cheaper on CPC Components at £8.18 +vat (stock no INO4874), there is also one available on ebay for mini blade fuses as well.
I have had a couple of fuel pump issues with P38 Range Rovers recently and found that fuel pumps on the way out draw about 8 amps but new ones draw about 3.5 amps.
Obviously if the problem you have is an intermittent short in the pump unit then a meter is not much use.
HTH Shaun.

Hi guys,
Thanks for your input, I know I should have scoped the pump curent but it was a quick call-out on both occasions just to get them going and if either of them come back that's what I'll do.
Thanks again.
Derek

Scoped pump current and couldn't find anything wrong but going to fit a new pump anyway.
Derek

Hi Derek,
Just wondering, when you scoped the pump current did you start scoping whilst pump was already running, or did you start your scope then turn ignition on and then start engine to see pump start up current ?

Regards
Dave

If your not 100% sure its the pump or the wiring, Why not fit a second fuse directly before the pump.

That way if it blows the first one, you know its a wiring fault, it it blows the second one, its got to be the pump. ?

How much current does the pump take. ?? If its only 5/6 Amps max, You could fit something like a 10 Amp fuse near the pump and if it takes that one out first its likely to be the pump causing the problem and its a little bit safer.

( if it more than that you could fit a 20 amp at the front and a 15 amp at the rear )

Theres always a possibility that fitting anything larger than the the rated fuse could cause the wiring to burn out rather than blow the fuse but you need a definite diagnosis to save hours or days of unecessary labour.

( In fact it doesn't always need a larger fuse to burn the wiring out it can do it with a standard fuse )

Always a Scarey thought of shorts and sparking inside fuel tanks but its supposed to be relatively safe. ( As long as its not in my fuel Tank )

H.T.H. Tony.

Hi Guys,
Thanks for the further input. Yes, higher rated fuses and fuel tank is what got me thinking I'd put a new pump in anyway, and if I was a master electrician like you Tony I'd probably take on a lot more of these sort of jobs. If only they'd made the hole under the seat a bit bigger! Even thought about opening it up with some tin snips but didn't want the customer to see me butchering his nice car! Have told customer to give me a ring when the fuel level has dropped a bit as it's got about three quarters of a tank in it at the moment.
Thanks again,
Derek

Hi all,
Fitted new pump, wasn't too bad after all, tank dropped out easy enough and went back together again nicely. Peace of mind now, they're an old couple and didn't want it letting them down again, although the 20 amp fuse seemed to be working OK.
Regards,
Derek