500 (Classic) Classic Fiat 500 not starting

[smithy202098]

Hi All, my first post on here so here goes! I have a 1872 Fiat 500L I have had problems starting the car found no fuel was being drawn from the tank. So I replaced the pump and after a few starts it fired up. After having it standing for some months the same problem has started again. So could this be a worn pin that operates the pump and if so how do I over come this?
Many thanks

 

[Luxe]

Based on your vehicle year it should be a horse drawn carriage, lol. Have you removed spark and separated the line coming off the pump to see if any fuel pumps out?

 

[gordinir8]

Based on your vehicle year it should be a horse drawn carriage, lol.

Still laughing.

 

[Toshi 975]

Hi first question is do you have a manual for the car I would say that it is essential with these cars unless you want to pay a fortune to a garage that probably have no experience of these cars anyway.
With the fuel pump spacer and two gaskets in place the fuel pump push rod should protrude between 1.5 & 4.0mm beyond the outer gasket face as the engine turns over which can be done by hand, spark plugs out if necessary. This can be adjusted by different thickness gaskets.

 

[the hobbler]

I have run into this problem myself---after not using the car for about 4 weeks (especially after a good run) I have found the car very reluctant to start. A good squirt of "Clutch and Brake Cleaner" (as good as 'easy-start', but cheaper) made the engine burst straight into life---I knew then that the only cause of 'non-starting' was a lack of fuel in the carb. The solution turned out to be very simple---by using the small electric tyre pump I had 'acquired' from my son I pressurised the fuel tank (hold the pipe from the pump to the tank in where the filler cap fits with rag to 'seal' the tank as you pressurise it)--this forced fuel through to the pump. A quick squirt of 'B + C Cleaner' into the carb enabled the engine to start, which then gave the pump the chance to put fuel through to the carb--simples!
I have given the cause some thought---is the engine heat (especially after a 'good, hard' run) vapourising the fuel; in the carb? The pump-rod is definitely adjusted correctly--even at just under 6,000rpm and going hard, there is no engine hesitation due to lack of fuel. I have fitted a 'one-way' valve, initially between the pump and the carb, to see if this will cure the problem--it may be that I will have to re-fit the check-valve just ahead of the pump; only time will tell.

 

[fiat500]

Half the time we're talking about cars over-fueling and whether or not it's necessary to allow it a return pipe and then we're concerned that fractional differences in actuating-rod length might lead to under-fuelling. Notwithstanding the fact that I agree that these things matter I don't believe that the setup was originally so finely balanced.
Most older cars seem to lose fuel from the carb bowl over a few days' rest by evaporation. In my experience, under those circumstances, it takes no more than two or three very short bursts on the starter to get fuel through to the carb. And I was told by an old-time mechanic that any "Easy-start" type product should be a last resort as it could get the engine addicted.

 

[Bigvtwin996]

any "Easy-start" type product should be a last resort as it could get the engine addicted.

I have to confess I am quite addicted to "easy start" now... my chainsaw and Strimmer love it... has no effect on the Lawnmower...

 

[giardini]

Is "the same problem again" no fuel being drawn, or just the car not starting ?
Standing a few months can hardly wear a pump pin that worked before, but it does wonders for corrosion buildup on the push-fit HT connectors in the coil and distributor cap... Do you have a spark ?
A decline in pump efficiency would first affect full-throttle operation, not starting.
As for pressurizing the tank with a bicycle pump, I don't know Hobbler, what that might do to your sanity's reputation in the neighbourhood :shakehead:
There must be a better way !

 

[fiat500]

I have to confess I am quite addicted to "easy start" now... my chainsaw and Strimmer love it... has no effect on the Lawnmower...

Does it get you going and what's your spark like?

 

[the hobbler]

With a bit of luck my neighbours will never know---I do it in the privacy of my garage/workshop! I know the method sounds strange, but it works. I only have to run the pump for a couple of minutes (it is an electric pump)---trying to start the engine by 'just cranking it over a few times' I can assure you, didn't work.

 

[fiat500]

With a bit of luck my neighbours will never know---I do it in the privacy of my garage/workshop!

When you consider the warning given on the engine lid about the danger of self-siphoned petrol when you remove the supply pipe at the pump, it seems likely that something could be tweaked to stop that problem. I doubt that all of the petrol in the line is evaporating so I wonder if you have a slight vacuum being created with the fuel tank cap? Or maybe a slight draw of air in one of the pipe connections?

 

[the hobbler]

I have found Peter that I do not have to remove the supply pipe to the pump--but I am very careful. I still have a number of possible causes of the problem to look into, but your thoughts are much appreciated (I don't seem to have any leaks in the system), but it is all a bit baffling.

 

[fiat500]

I have found Peter that I do not have to remove the supply pipe to the pump--but I am very careful. I still have a number of possible causes of the problem to look into, but your thoughts are much appreciated (I don't seem to have any leaks in the system), but it is all a bit baffling.

I wasn't clear on what I said.... I'm meaning the general warning that Fiat give to us all which indicates that there ought to be a free flow of fuel in that pipe.

As I am on a boring aeroplane journey from Portugal I have been trying to get my head round various car problems including this one. Is it possible that the problem is related to the fact that you have the modification of a fuel return pipe from the carb which joins the fuel supply pipe just behind the pump? Given that the carb will be more or less empty in the situation described and thus the needle-valve will be open in the carb. When the suction of the pump is split at the Tee-connection it will have a tendency to draw air via that pipe-branch rather than fuel from the main supply. You could discount that as a possible cause by temporarily clamping the return pipe and trying to start the engine.*

I'm sure that the return could be fitted after the pump, especially if it was fed in via a reverse "Y"- connector.

 

[1500500]

One of my friends attached a squeezy pump to the fuel line near the fuel tank. Same as fitted to outboard motors on boats. A few squeezes and the car fires up no problem.

(In regards to using easy start on garden equipment that may have saved my brothers string trimmer that annoyed him so much he threw it over the fence into his neighbours yard.)

 

[fiat500]

One of my friends attached a squeezy pump to the fuel line near the fuel tank. Same as fitted to outboard motors on boats. A few squeezes and the car fires up no problem.

(In regards to using easy start on garden equipment that may have saved my brothers string trimmer that annoyed him so much he threw it over the fence into his neighbours yard.)

I had the chainsaw from hell that matched your brother's strimmer; after weeks' of on/off messing about and several new parts I just decided to use it for spares and bought an identical new one as they are so cheap these days.
You'll no doubt be aware (having an Austin 7) that this issue was easy to overcome as early cars had a very positive, hand-priming lever on the fuel pump.

 

[Bigvtwin996]

I had the chainsaw from hell that matched your brother's strimmer;

blimey I hope you know the difference between a chainsaw and a strimmer...
However I did once cut my lawn with a hedge trimmer...

I was actually getting worried about what Tom gets up to in the privacy of his workshop... I had visions of Paul Barber in the Full Monty...

 

[fiat500]

blimey I hope you know the difference between a chainsaw and a strimmer...

Of course I do...you can't cut your hair with a strimmer.

 

[gordinir8]

The solution turned out to be very simple---by using the small electric tyre pump I had 'acquired' from my son I pressurised the fuel tank (hold the pipe from the pump to the tank in where the filler cap fits with rag to 'seal' the tank as you pressurise it)--this forced fuel through to the [email protected]/images/smilies/confused.gif[/IMG][IMG]https://cdn-i.fiatforum.com/images/smilies/smile.gif[/IMG]

I am doing the same thing sometimes but with my mouth. I am sealing the tank with both my hands and then...blowing into the tank.

 

[fiat500]

I am doing the same thing sometimes but with my mouth. I am sealing the tank with both my hands and then...blowing into the tank.

I am trying to work out which method is safer! At least your mouth probably can't give out any sparks.

 

[giardini]

I'm half expecting the next one to explain how he maintains a bean-rich diet and takes it from there...