Technical Intermittent fuel pump problem

[nephilim]

Hi all,

Got a '93 1.0 fuel inj uno that has a problem with the fuel pump. Usually it can be heard when the ignition is turned on, but it now doesn't always sound. If it works, it will start for about 5 seconds then stop, after that it might not turn over the pump for a while - and not start. But then continuing you will hear the pump, starts for 5 seconds, then stops.

Managed to track down the pump underneath the passenger seats. So is this a problem with the pump, can it be sorted or is it time for a new one. Could it be something else like a blocked fuel filter etc. Never changed these, not too sure where they are on the car!

Any help, much appreciated, thanks for looking.
Cheers.

 

[Ucof]

Ah, the joys of fuel pumps and filters.


The filter is an easy one - looking into the engine bay, it should be a round cylinder, with a pipe at each end, in the top left corner. It is usually silver metal, but I have seen clear plastic ones so you can tell how gunked up the filter is. The will be a plastic shroud around it, keeping it in place, but is easy to see.

The fuel pump, like you said is under the rear seats. Whip the seats forwards and take the carpet up. You will see a black plastic cover, un-screw the 2 screws and remove the cover. The first thing to always try is just to reverse the polarity on the pump, to reverse the direction of the fuel flow, and hopefully remove any gunk that has accumulated in it, which might be causing it to malfunction.

Other than that, buy a new one on ebay, there's loads around, but just get the vendor to double check that it will fit your car - there are a surprisingly large number of different types. They aren't too expensive either really.

 

[tattyoldvan]

good advice from ucof as ever.
but before you spend dosh on a new pump, have a look at the relay and the wiring.
the lil conector on the pump housing is rubbish, and could be corroded, plus fiat use wire awg that is half that of the actual pumps wire.
First locate the relay, lil black plastic cover with thumb screw on the passenger side under bonnet. pull out relay and bridge the terminal with some handy wire.
as you say it operates for few seconds i'd say a sticky relay, if the pump now flows continuously get a new relay.
if the problem still exists run a couple of cables direct to pump, if still no life its the pump.
dont go to auto factors as the'll want to sell you pump and float assembly. best bet is ebay or just grab a couple from breakers. I'm using a 4.0l cherokee one atm, very similar size, but far better gauze pickup and flow rate is much improved!

 

[nephilim]

Thanks for the replys, a few things for me to look at and try. A couple problems though, sorry to be a bit thick but I am confused with:
reverse the polarity on the pump
How is that achieved?

and
bridge the terminal with some handy wire.
Not too sure of that one too!

Thanks for your patience,

Cheers

 

[Kozmos]

reversing polarity, instead of the bulb it's your pump, change the positions of the wires

for you i think the relay are on the drivers side, lef side of the car, and there are 2 relays, not sure withc is for the pump, bridging means that you take out the relay an stick a short wire between pins witch the relay should connet, doing so, you're doing it's work.

 

[nephilim]

Thanks to all who helped, fixed it, it certainly was the pump, managed to reverse the polarity, ran it a couple of time, put it back to how it was and hey presto, starts and keeps running! Well pleased, so thanks again.