Hi, Co Fiat Owners

Tearing my hair out again with this Punto. Started with a jerk every now and then like a dirty fuel filter. Changed it but still done it. Eventually, it just cut out and left me in the rain.

The fuel injector light came on but does not go off when pushing the remote button so it won't start.

Normally I put the key in and on the first turn the light shows. When I push the button the light goes off and it starts. Now the light is off on the first turn then it comes on when pushing the remote.

This was telling me the injector not getting fuel I presume.

Next step I removed the fuel pump as I noticed it is not running. After testing it with 12v from the battery it works but no power on the back connection.

I checked and even changed all fuses but not sure what the next step is. Browsed the forum and followed some advice but still no luck. My question what is the next thing to check? Where does it get power from?

its not an injector light, its the engine management light...

best thing to do is read the codes... you need a fiat 3-pin to OBD adpator, a vagcom cable (both available for just couple of quid on ebay) and some software to read them, MultiEcuScan is the go to software, free version is all you need to read and clear codes.

However, if the pump is not priming when you turtn ignition on, there isnt many things that would do that... If i understand you when you turn ignition to accessory position your engine management light doesnt come on at all now? what about the code light, does that come on and go off as it should?

Fuel pump relay could stop it priming also, sometimes called the twin relay.

I'd say inertia switch but that doesnt stop the pump getting 12v, it is on the earth side.

Hi Blu


Talking about this light. Used to be on until key activated then will go off and the vehicle will start. No, it's off and when I activate key it comes on. Engine management light and code lights work as it normally does.

Would like to know where the electrical feed comes from the front so I can test it.

that there is the engine management light, thats what i'm saying. So i dunno what light you think the engine management light is if you say its working normally, cause that is it.

normal operation would be is comes on for a moment when you turn ignition on for a few seconds and then go out again. Apart from that it should never come on. And its got nout to do with injectors.

power to the pump comes from the fuel pump relay, mounted under a plastic cover on the firewall, should be under a little plastic cover but its often missing - its a little white box. The relay is activated directly by the ecu, i dont have pinout to hand so can't tell you what pin of the ecu.

fuel pump relay looks like this....



If its ever been changed (unlikely, these are pretty bombproof too) it might be brown or even green in rare circumstances.

Thanks, Blu

Cleared up a couple questions I had. thanks for the visuals it really helps. Like I said before on this forum not much assistance in South Africa think I am the only one in this country with this model. No, I'll carry on fault finding.

Regards

Tested relay working. Also tested and found 12v supply go through to the pump when turning the key. Can the pump be faulty? Put 12v straight from the battery and it worked but according to me very weak.

perhaps fuel filter is clogged and its struggling to pump past it??

They arent a known weak point but they can fail.. but almost no punto has ever had its fuel filter changed.. the mk1 has an inline filter, if you stand on side with fuel filler cap and look under the car you should see it. Just forward a bit from the filler cap iirc.

Is the tank on yours plastic or metal, they come with both. Its possible theres rust inside if its a metal one which could get in the pump and mess it up, they'd normally just stop working completely in that situation though.

I'd try whacking a new filter on, and if it still doesnt seem to work look at the pump itself.

The cloth strainer in the base of the pump casing gets blocked so badly the pump can't suck. It's happened to my 55S, just blow it through with the air line, gently.

If the pump is working, could the problem be the crank sensor?