Fiat Seicentro seems to run out of petrol, often with plenty in the tank

[George]

My daughter's 2001 Seicento behaved itself for a few weeks after purchase during which time I used it as she has a bus pass still.

I had a problem getting the key out of the petrol filler cap so I did not bother securing it but just laid it in the filler pipe for a while and shut the panel

After nearly half emptying the tank it would start to miss and gave all the symptoms of running out of petrol, I have a workshop manual on a dvd and when I saw that the tank pressure was monitored by the engine management co mputer I thought I had tumbled on the answer and sure enough, when I found out how the key came out of the cap and how to tighten it and get the key out, it did not occur again for a while. Then it seemed to come back but only if the tank was about half full and for a while I top ped it up whenever it got near that. Then a couple of days ago it happened again and the tank was 3/4 full. I topped it up, but still I think the pump was not operating, or so it seemed, I also found that if it starte d to die - if I switched the ignition off and on the flow started and away it went again. The engine was quite warm, but not overheated and I got it home by switching the ignition off and on.

Today - the engine being cold it started OK and I must have driven about 20 miles without a problem, but I am not confident. I asked the Fiat dealer about connecting to the engine management computer but they said this was v ery difficult (and expensive) The petrol pump is in the tank and they do n ot seem to have one and I am not sure this is the problem, anyway, (or the tank filler top, which is about £40.)

It seems it will cost more than I paid for the car to fix this and I am wondering if I can wire a separate petro pump to the ignition switch to bypass the problem. or at least run it in series, with the one in the tank.

Has anyone else experienced this and can make any suggestions? I would be very glad to hear from anyone.

Thanks and regards

George.

[tabbypurr]

he symptoms of running out of petrol, I have a workshop manual on a dvd an d when I saw that the tank pressure was monitored by the engine management computer I thought I had tumbled on the answer and sure enough, when I foun d out how the key came out of the cap and how to tighten it and get

opped it up whenever it got near that. Then a couple of days ago it happen ed again and the tank was 3/4 full. I topped it up, but still I think

ted to die - if I switched the ignition off and on the flow started and awa y

t home by switching the ignition off and on.

20 miles without a problem, but I am not confident. I asked the Fiat deale r

very difficult (and expensive) The petrol pump is in the tank and they do not seem to have one and I am not sure this is the problem, anyway, (or

The fault is that it's a Fiat. It sounds like a pump issue but could also b e fuel line blockage, filter blockage etc. Enging management reading things are cheapish on ebay/amazon.

NT

[Jethro_uk]

I once had a car where the engine would die every few weeks. Leave it a while, and it would go for another few weeks.

Turned out to be a leaf in the petrol tank ....

[Brian Gaff]

The question is really, how would the level of the petrol as long as its above the inlet to the pump, make any difference, unless its bunged up or something. What nutter made a petrol pump as part of the tank in the first place?

I suppose its not the old fault of evaporation in the pipework when the engine is hot and restarting won't then work since the weedy pump cannot cope with that air? This was a VW teendency as I recall from the number of times a friend had the issue!

Brian

[Harry Bloomfield]

Might the tank air vent system being obstructed, causing a higher than normal vacuum in the tank? Try taking the filler cap off, when it refuses to start, then see if it starts.

[Lee]

There was a recall for fuel tank corrosion in 2004, no clue whether yours would have been involved. That was for leaking fuel though, I think.

But if it does have a leak above the fuel level it might be pulling air in which could upset the ECU if it monitors such things. Or maybe just a blocked in tank filter that's full of rust...

[The Natural Philosopher]

You will know if its leaking fuel by te stink of petrol

most likely the fuel pump is on the way out - 10 years/100,000 miles seems about par for these.

Try changing all the fuel filters first.

If a new pump is more than the car is worth, scrap the car and buy something else for 500 notes.

the fuel pump assy is on ebay from 40 quid used and about £110 new.

Swap out shouldn't be more than an hours work.

So a sub £200 fix I'd say if you avoid main dealers.

Id guess that the fuel filler cap affected the tank vacuum enough to make the failing pump fail a bit more often. You should hear a little whine when the ignition is switched on as the pump creates pressure. No whine = U/S pump.

Sometimes banging a rear door near the tank gets em started again.

Should be a fuel pressure diagnostic in the ECU somewhere - if its below spec that's generally a pump change anyway.

[The Natural Philosopher]

Oh this shows how easy it is

Ok its a Punto, but IIRC the fuel pump location is similar and the pump spec is almost identical

My guess is that if you don't mind a bit of petrol spraying out, you dint need top depressurise the fuel system.

DO disconnect the battery though. No sparks when dealing with fuel systems.

[George]

he symptoms of running out of petrol, I have a workshop manual on a dvd an d when I saw that the tank pressure was monitored by the engine management computer I thought I had tumbled on the answer and sure enough, when I foun d out how the key came out of the cap and how to tighten it and get

opped it up whenever it got near that. Then a couple of days ago it happen ed again and the tank was 3/4 full. I topped it up, but still I think

ted to die - if I switched the ignition off and on the flow started and awa y

t home by switching the ignition off and on.

20 miles without a problem, but I am not confident. I asked the Fiat deale r

very difficult (and expensive) The petrol pump is in the tank and they do not seem to have one and I am not sure this is the problem, anyway, (or

Thanks for a lot of good ideas. The tank seems OK and the pump can be hea rd running when the ignition is switched on, when it is cold but I am fair ly sure that the supply to it is being switched off by the engine managemen t as the engine is obviously starved of fuel, but when I turn off the ignit ion it starts pumping again without any delay. it is hard to tell what the pump is doing when it goes wrong and there is some petrol getting through a s the engine surges back and forward as it gets fuel.

There seems no difference when I go fast or up a hill and once it has warme d up it can happen any time sometimes only running properly immediately aft er switching the ignition off and on. I have now bought a new free standin g pump which I shall try and connect to the rubber pipe that goes from the internal pump to the injection pump, and wire up to the ignition switch fus ed supply. When it happens there are no error conditions shown on the dash and I think putting in a pump to keep the flow going might do the trick, w ithout spending a fortune. I do not expect the pump in the tank will block the flow either and if it circulates back to the tank this will still take place anyway without falling foul ot the monitoring. I don't mind treating the symptoms, if it works OK afterwards.

Thanks for all the advice. Regards George.

[Lee]

Just be aware of the safety implications. You can get standalone fuel pump relays with engine run sense, but it would probably cheaper to fix the problem :)

[Lee]

More of an issue with in-tank high pressure pumps though, to be fair.

[Fredxxx]

And AFAICR the Seicento has an in tank pump. Although not 'high pressure' I'm sure it can empty a tank PDQ.

[Fredxxx]

There is a lift pump in the tank, though not sure if it is high Pressure.

There is a Shrader valve on the high pressure side and I have in the past considered connecting a gauge.

Have you go access to a EOBD connector? That will give access to the ECU and mixture adjustment etc.

[George]

he symptoms of running out of petrol, I have a workshop manual on a dvd an d when I saw that the tank pressure was monitored by the engine management computer I thought I had tumbled on the answer and sure enough, when I foun d out how the key came out of the cap and how to tighten it and get

opped it up whenever it got near that. Then a couple of days ago it happen ed again and the tank was 3/4 full. I topped it up, but still I think

ted to die - if I switched the ignition off and on the flow started and awa y

t home by switching the ignition off and on.

20 miles without a problem, but I am not confident. I asked the Fiat deale r

very difficult (and expensive) The petrol pump is in the tank and they do not seem to have one and I am not sure this is the problem, anyway, (or

I looked for the access to the top of the tank inside the boot, as per the Punto YouTube video, but the boot hold the spare wheel and is too low, so I lifted up the rear seats and found a panel bolted to the floor, which look s like access to the tank top. I tried to find a section in the DVD I have about getting into this but it written in language that is not familiar to me. Nor I am afraid, is the ref. here the connector I might need. In anot her life I was a mainframe computer engineer working for ICL and I am not a fraid of technology, but wherever possible I usually apply solutions that g o back to basics rather than trying to understand all the latest technology . E.g. if the fuel is failing to get out of the tank, let me try and provi de help for this in a way the does not screw up the complicated system that exist and which provides me with a basic fix that works. Will my addition of another pump work? I can see it as a simple solution. Having said that I shall have a look under the cover after disconnecting the battery - hopin g I do not lose the code for the radio and see if I can recognise the filte r, which I agree might be blocked.

I am sorry to see this trend in all sorts of devices, when I asked the manu facturer of a clothes dryer for the wiring diagram for the 10 year old mach ine, they basically told me to bugger off as they did not want to help and would much rather I bought another machine. It was not rocket science and I fixed it without their help and it is still working fine.

Having worked 30 years in the oil industry I am deeply aware of the health and safety aspects of anything I do but I don't let them stop me. Vive la D IU. I hate this throw away trend and hope that a possible future depressio n will return us to a time where people go back to repair and recycling, an d manufacturers are obliged to produce things that can be fixed rather than thrown away.

Once again thanks for all your help.

Regards George.

[Fredxxx]

If you don't have access from above its 3 bolts to remove the tank.

My gf's tank was leaking but the car was outside the recall years.

I echo your sentiment. Personally I think greens and the EU should have pushed for the publishing of official repair manuals after a guarantee period has expired.

[NY]

Yes we need to get back to the spirit of trying to repair first and only if that isn't possible then investigate replacing. And that requires changes in design to make repair (or replacement of individual modules/components) possible: don't glue or heat-weld - use proper screws. Technology should be

*designed* to be user-repairable - or at least, repairable by your local electrician etc. It requires a plentiful supply of spares at cost (rather than with a horrendous mark-up on the price).