General FIAT 500D CUTTING OUT THEN NOT RESTARTING AFTER 2 MILES

[handy andy]

THANKS TO EVERYONE FOR THE HELP I HAVE RECIEVED RE MY FIAT 500 BREAKING DOWN
UNFORTUNATELY I HAVE TRIED EVERYTHING BUT THE PROBLEM STILL PERSISTS
I .E ON COLD START UP EVERYTHING IS FINE BUT AFTER ABOUT 2 MILES RUNNING IT CUTS OUT NOTABLY AT JUNCTIONS
IIT WILL NOT RESTART UNTIL YOU WAIT ABOUT 10 TO 20 MINUTES AND COOLED OFF
I WAS WONDERING THAT PERHAPS THE THERMOSTAT IS NOT WORKING AND THAT THEREFORE THE ENGINE IS GETTING TOO HOT AS IT SEEMS TO BE HEAT RELATED
I HAVE EXHAUSTED ALL PREVIOUS POSSIBILITIES SO I DONT KNOW WHERE TO GO NEXT
HAVE CHANGED
PLUGS
CB POINTS
DISTRIBUTOR CAP
COIL
CONDENSER
CLEANED ALL JETS IN THE CARBURETTOR
CHECKED FILTERS IN TANK AND PUMP
ANDY
LINCOLN

 

[the hobbler]

THANKS TO EVERYONE FOR THE HELP I HAVE RECIEVED RE MY FIAT 500 BREAKING DOWN
UNFORTUNATELY I HAVE TRIED EVERYTHING BUT THE PROBLEM STILL PERSISTS
I .E ON COLD START UP EVERYTHING IS FINE BUT AFTER ABOUT 2 MILES RUNNING IT CUTS OUT NOTABLY AT JUNCTIONS
IIT WILL NOT RESTART UNTIL YOU WAIT ABOUT 10 TO 20 MINUTES AND COOLED OFF
I WAS WONDERING THAT PERHAPS THE THERMOSTAT IS NOT WORKING AND THAT THEREFORE THE ENGINE IS GETTING TOO HOT AS IT SEEMS TO BE HEAT RELATED
I HAVE EXHAUSTED ALL PREVIOUS POSSIBILITIES SO I DONT KNOW WHERE TO GO NEXT
HAVE CHANGED
PLUGS
CB POINTS
DISTRIBUTOR CAP
COIL
CONDENSER
CLEANED ALL JETS IN THE CARBURETTOR
CHECKED FILTERS IN TANK AND PUMP
ANDY
LINCOLN

The chances of the engine being too hot to run after just a couple of miles is remote. 1 thing that you haven't mentioned in your list is whether you have checked the base of the carb and the bakelite spacer for warpage---a not uncommon fault. When the engine is running, spray some carb cleaner or brake cleaner around the base of the carb---if the revs alter, there is a fair chance that the carb base or/and the bakelite spacer is warped. These need to be flattened out.

 

[handy andy]

THANKS FOR YOUR HELP
YES I HAVE TESTED TO SEE IF THE BAKELITE BASE UNDERNEATH THE CARB IS WARPED BUT ITS FINE
NO CHANGE IN ENGINE SPEED
ANDY

 

[the hobbler]

THANKS FOR YOUR HELP
YES I HAVE TESTED TO SEE IF THE BAKELITE BASE UNDERNEATH THE CARB IS WARPED BUT ITS FINE
NO CHANGE IN ENGINE SPEED
ANDY

Have you checked and adjusted the tappets?

 

[handy andy]

Have you checked and adjusted the tappets?

YES I HAVE

 

[Toshi 975]

I have sympathy with you Andy as when I fist got my 500L it did pretty much the same as your car. It drove me bonkers for about 15 months. After checking and changing everything imaginable I knew it was ignition related. At one stage I had two coils mounted on the car and ran on one. As soon as the engine cut out I stopped the HT lead and the car would immediately start.
final throw of the dice , I fitted a new coil and electronic ignition and the problem never showed again.
on a Fiat 126 I tried the later type ignition with no distributor cap and a twin spark dry coil. I managed to burnout two brand new coils in the matter of a couple of days and then discovered I should have fitted a ballast resistor.

 

[TeleSpeed]

As soon as it dies and before it cools down, check to see if you have a blue spark to the plugs.

 

[TeleSpeed]

Be mindful that new parts can be faulty.

 

[the hobbler]

I am not sa

Be mindful that new parts can be faulty.

I am not saying that the new condenser is faulty, but modern condensers are built very cheaply---nowhere near the quality of the O.E. units. For this reason I always recommend the fitment of the "Swiftune Competition" condenser. These condensers , being that they have a long 'feed' wire as well as long 'earth' wire, can be mounted remotely from the distributor---up by the coil and away from the heat of the 'cooling' air that comes from the engine. They are also built to high standard.

 

[RDS]

Andy I appreciate that you have looked at the carb jets but did you check the operation of the float valve. That was the cause of my episodes in another Fiat.....the valve would stick closed and not admit fuel into the bowl until cool, then the process would start again. A thorough ultrasonic clean and new valve sorted that problem.

 

[hodgy18]

Mine since adjusting the tappets has always ran better when hot. Not sure if it is a common mistake that people assume they have a 650cc engine for example fitted. I did as this was on the V5 and the previous owner thought it was, but under further investigation found it to be 590cc. So after adjusting the tappets to correct gap, has since ran better, and cleaning out the carb.
Always worth looking into, just incase

 

[Ralf S.]

How does it die? If it just cuts out then that’s an electrical problem. I would look at the coil or the fuel pump.. although your beast might have a mechanical pump.

If it dies by kind of losing power and then stopping then it’s more likely a fuel problem.. either the carb float as has been mentioned, or a fuel pump problem.

You can test the coil by immediately swapping yours to an auxiliary coil kept handy for just this test.

You can test the fuel pump by removing the fuel line at the carb and turning the engine over. Catch any fuel that comes out in a small clean jar..

Ralf S.

 

[RDS]

if you suspect the condenser (they often get a bad reputation and often unfairly) especially because of its position above the exhaust silencer, you can also rig up a spare condenser with the connections ready to plug straight in place of the suspect one. This is a boon by the side of a busy road and heled me dismiss that as a cause.

To see if I had a spark when stranded by the roadside, i also fitted a spare plug on a bracket in the engine bay so that I can swap over the king lead from the coil direct to it and crank. If there is a spark, do the same with each plug lead in turn this will narrow the fault down (leads/rotor/cap etc). No need to take the plugs out at this stage if caught out on the road, do that when back at base.

RDS

 

[Tinyotim]

I’m chasing exactly the same issue and have been for sometime now .
Car runs perfectly for half an hour or so , cuts out at junctions then wait ten mins and it starts rinse and repeat.
I’ve done ,
New carb ( float set properly)
New leads
New plugs
New points and condenser
New fuel pump
New fuel lines
Valve clearances set correctly
It has new fuel tank and filters

The only thing I haven’t replaced is the distributor, looking online at new ones yesterday I noticed that they all come with a nice gasket to seal them to the block , (light bulb moment).
I’ve had mine off for the first time this morning and surprise surprise no gasket.
Metal to metal has got to transfer lots of heat surely?
Lots of heat through the dizzy has got to play havoc with the timing?
Does anyone know how thick this gasket should be ? As I have lots of gasket paper knocking around and can make my own.

Thanks and fingers crossed

 

[fiat500]

I’m chasing exactly the same issue and have been for sometime now .
Car runs perfectly for half an hour or so , cuts out at junctions then wait ten mins and it starts rinse and repeat.
I’ve done ,
New carb ( float set properly)
New leads
New plugs
New points and condenser
New fuel pump
New fuel lines
Valve clearances set correctly
It has new fuel tank and filters

The only thing I haven’t replaced is the distributor, looking online at new ones yesterday I noticed that they all come with a nice gasket to seal them to the block , (light bulb moment).
I’ve had mine off for the first time this morning and surprise surprise no gasket.
Metal to metal has got to transfer lots of heat surely?
Lots of heat through the dizzy has got to play havoc with the timing?
Does anyone know how thick this gasket should be ? As I have lots of gasket paper knocking around and can make my own.

Thanks and fingers crossed

I doubt its a lack of a gasket. They are very thin paper in any case. I don't use one and simply have a thin wipe of sealant.
Heat can negatively affect the condenser, but the distributor is otherwise, entirely mechanical.
When I have suffered that same type of elusive issue it has usually been traceable back to changing something, which has then resulted in the engine being too hot. It's hard to know how hot is "too hot" because "quite hot" is normal.

I would very carefully reset the gap on the ignition points (if fitted), very carefully set the static ignition timing and then chack and adjust the with a timing gun to get the dynamic advance correct.

Ideally, then use a Colortune to get the fuel/air mixture spot on, followed by rechecking the dynamic advance.

What this may show you is that your distributor has a fault or there is something wrong preventing the carburettor being adjusted properly.........or it may sort the problem out.

 

[Tinyotim]

I doubt its a lack of a gasket. They are very thin paper in any case. I don't use one and simply have a thin wipe of sealant.
Heat can negatively affect the condenser, but the distributor is otherwise, entirely mechanical.
When I have suffered that same type of elusive issue it has usually been traceable back to changing something, which has then resulted in the engine being too hot. It's hard to know how hot is "too hot" because "quite hot" is normal.

I would very carefully reset the gap on the ignition points (if fitted), very carefully set the static ignition timing and then chack and adjust the with a timing gun to get the dynamic advance correct.

Ideally, then use a Colortune to get the fuel/air mixture spot on, followed by rechecking the dynamic advance.

What this may show you is that your distributor has a fault or there is something wrong preventing the carburettor being adjusted properly.........or it may sort the problem out.

Thanks for your comprehensive reply,
The search will continue ,

One other thing I have noticed is when I set the mixture screw in the new carb ,
Screwing it in works as it should and the engine dies if it’s screwed in too far , however screwing it back out brings the revs back but keep screwing out and it makes no further difference.
I’ve always thought it would also die if screwed out to far ( making it too rich ) ?

 

[fiat500]

Thanks for your comprehensive reply,
The search will continue ,

One other thing I have noticed is when I set the mixture screw in the new carb ,
Screwing it in works as it should and the engine dies if it’s screwed in too far , however screwing it back out brings the revs back but keep screwing out and it makes no further difference.
I’ve always thought it would also die if screwed out to far ( making it too rich ) ?

I'm not sure that the engine must completely die, but it usually runs so badly at that setting that the engine chugs itself out.
It maybe points to an airleak at the carburettor, which benefits from the extra fuel. I assume you've already been able to find that sweet-spot on the mixture screw, where the engine runs slowly but smoothly?

 

[Tinyotim]

I'm not sure that the engine must completely die, but it usually runs so badly at that setting that the engine chugs itself out.
It maybe points to an airleak at the carburettor, which benefits from the extra fuel. I assume you've already been able to find that sweet-spot on the mixture screw, where the engine runs slowly but smoothly?

Yes , it starts first turn and runs like a Swiss watch for half an hour , I’ve fitted new gasket and baseplate under new carb , tested it by spraying it for air leaks etc etc .
It’s baffling, I’ve done this sort of stuff for years with just a basic timing gun and tools .
Never known anything bog me down like this before.

 

[fiat500]

Yes , it starts first turn and runs like a Swiss watch for half an hour , I’ve fitted new gasket and baseplate under new carb , tested it by spraying it for air leaks etc etc .
It’s baffling, I’ve done this sort of stuff for years with just a basic timing gun and tools .
Never known anything bog me down like this before.

Is the fuel pump tightly secured? I once had one working loose that wasn't delivering enough fuel.
Related to that, it's oft quoted that the pushrod that activates the pump must protrude by a very precise amount from above the gaskets and spacer on the block. That will have been so when using an original part. But aftermarket pumps have all sorts of lever construction, and I've had a situation where the pump was working fine, but the rod didn't have sufficient stroke to deliver enough fuel in some circumstances.

 

[Tinyotim]

I can't remember the exact distance that the rod should travel in and out of the block , but when I fitted the new pump I looked it up and checked it.
it was travelling in and out as per spec .
Such a simple little engine, Now bangs head on wall !