Technical Punto HGT Fuel Pump

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Technical Punto HGT Fuel Pump

TidyBoy

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Nov 21, 2003
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I think my Fuel Pump on my HGT has died :( Thuresday morning i started the car and it ran for about 10 seconds and then will not start again. (must have been pertol left in the in fuel line in the engine or something).. The fuel pump does not seem to be priming when i turn / start the ignition.

Is there anything else i can check befoe looking into buying a new fuel pump. Ive had a look in the fuse boxes but cant seem to find a fuse, can anyone tell me if there is one there? or is ther anything else that can cause this problem.

In the event that i do need to buy a new pump, can anyone confirm weather the HGT pump is the same as a pump on any other fiats. being a HGT if i have to buy it from Fiat it bound to be big £££ :(

Thanks, Adam
 

DanGil

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Check the fuel cut off switch in the passenger footwell, i've had one give up for no reason.
 
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TidyBoy

TidyBoy

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Ok,. I have chance to have a proper look at it now.
I checked the cut off switch which did seem to click back in when pushed. Tried to start again but same situation. (Checked the switch afterwards and it has stayed back in)

I have borrowed a friends multi-meter and between us we have managed to establish the following.

4 wires in connector to pump.

Black and White Thin Wire - (Earth)
Black and Red Thin Wire - (feed for fuel guage)

Purple and Yellow Thick Wire - When the ignition is turned 12v is supplied through this wire for 3-5 seconds (Primeing Sequence I guess). After 3-5 second no currenct detected. If the ignition is turned further to crank the car over the wire reads around 9v.

Purple (Solid) Meduim Wire - in any scenario I have not been able to read a current on this wire at all. Primeing phase and cranking phase.

The petrol guage is working.

Interstingly we disconected the cut-off switch completly and still we read 12V primeing , 9V when cranked on the Purple and Yellow wire. :confused:

Does the above indicate that the pump has had it, or is the Solid Purple Wire the key here.

Thanks, Adam
 
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TidyBoy

TidyBoy

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Update - More testing and results.

I have taken the 'Cut of switch' off and proved it is working ok. Continuity test works between Pins 1 and 3. Not sure what pin 2 does but there is no pin 2 in the connector which plugs into the cut off switch.

Continuity test OK between start and end of wire 4. Wire connecting Cut Off Switch to Fuel Pump Connector.

Continuity Test between Wire (5) and car chassis comes back positive. Does this perhaps indicate the 'cut off switch' cuts the earth connection to the pump. (even though there appears to be a working earth (1) but maybe this is only an earth for the fuel level)?

Hopefully my very very very basic digram kinda of explains the above.
FPumpLoomDiag.JPG
 

DanGil

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Jan 23, 2006
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It does indeed cut the earth, its a safety feature.

Have you checked for fuel at the rail (its on the right hand end of the rail, push the valve in while cranking and it should have petrol there)?

If you have'nt, link out the cut off switch with a bit of wire just to make sure its definately working.

(bear in mind it takes a few goes to get petrol back round the system).
 
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TidyBoy

TidyBoy

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Cheers Dan, I did link out the cut off switch earlier and still nothing happening. I didnt check the fuel rail but the pump is not priming. Im fairly confident that this is now indicating that the pump has broken.

Cheers for your help.. will keep the thread updated with progress. Hopefully this will help clairfy fuel pump problems for mk2 owners in the future.
 

DanGil

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No problem mate, i'll be interested to know what the problem is as mine was just the cut off switch. Like you say if its got a feed the pump must be faulty.
 
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TidyBoy

TidyBoy

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Just though i would post up a conclusion to my fuel pump problem.

After taking the fuel pump out I could see that the wire tracking down from the connector to the actual pump had burnt out! there was an inch long section were the wire sheath had burnt off and the wires had turned black and brittle. I was a bit shocked as this wire is in the fuel tank with nothing between it and the petrol!

I had a look at my fiat tech CD which pointed out that any pump from a petrol mk2 punto should fit;


Validity.JPG


This was good as the chances off getting a pump from HGT were slim and none, luckily there are loads of 1.2's at my local scrappy so I went up and managed to get one for £30 from an ELX.

Replaced back into my tank, connected everything back up again and all is back to normal!!
 

charles_collins

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Dec 8, 2007
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does anyone happen to know a location for the cut off switch, i read its in the passenger footwell but whereabouts, all i can see is the air conditioning unit, mines a hgt too..., any help much appreciated
 
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