Technical Fiat 500 not cranking

[hussnain]

Hi,

If anyone could help it would be great..
I have a Fiat 500 pop 1.2 2009 and its doing my head in. I bought the car for a cheap £500 with a diagnostic report from Fiat themselves which said it needed a new ECU. I have bought and put on a new ECU, new fusebox and new ignition barrel and the car still does not crank.

I then thought maybe its the starter so fussed around for 3 days replacing the starter, got there in the end but only to realise that hasnt fixed the problem.

I also replaced the battery for a brand new one which hasnt done anything.

I then thought lets check the connections/wires. Traced the wires from the fusebox, they look fine not burnt.. Checked the wires on the battery and sanded them down.. Checked the cables from the starter and sanded them down too. Literally all there is is a click when turning the key to start position.

Where can I look now?

Thanks.

 

[John202020]

Plain brown wire from ignition switch goes straight to starter try a direct feed to it to see if it cranks? Do this ignition off.
Where does the click sound come from, inside the car or under bonnet?

 

[John202020]

A Haynes manual might help or a auto electrician?
You have checked the engine earth strap?
Have you checked the solenoid brown start signal wire with say a 21w bulb to see if it lights when turned to start?

 

[varesecrazy]

Fuel pump running?

Just no effort from the starter..

If it clicks it sounds likr a lack of electrical power..

Use a booster earth cable..

And try again

 

[portland_bill]

Hi,

If anyone could help it would be great..
I have a Fiat 500 pop 1.2 2009 and its doing my head in. I bought the car for a cheap £500 with a diagnostic report from Fiat themselves which said it needed a new ECU. I have bought and put on a new ECU, new fusebox and new ignition barrel and the car still does not crank.

Just the one ECU? New or used?

There is an ignition ECU and a body computer that both hold the key immobiliser code. Both need to agree that the key is acceptable.

A report from Fiat, as in Fiat UK, or as in local Fiat dealer? Did they say why it needed a new ECU?

Often complete sets of both computers, and a key set, from a scrapped car, are available on Ebay. Such as this will make your car electronically assume the identity of the scrapped one, and should then function. Need a set of same spec or above. A lower spec may lose some of the higher spec additions as teh body computer will not know about them.

 

[typecastboy]

Just the one ECU? New or used?



There is an ignition ECU and a body computer that both hold the key immobiliser code. Both need to agree that the key is acceptable.



A report from Fiat, as in Fiat UK, or as in local Fiat dealer? Did they say why it needed a new ECU?



Often complete sets of both computers, and a key set, from a scrapped car, are available on Ebay. Such as this will make your car electronically assume the identity of the scrapped one, and should then function. Need a set of same spec or above. A lower spec may lose some of the higher spec additions as teh body computer will not know about them.

I think he meant the body one when he mentioned the fuse box.

 

[waterfielda]

seems we have similar problems with different engine configurations. do you have MES or alfaobd? Can you communicate with any modules?

 

[John202020]

It doesn't crank,,,, there's very little it can be going off the circuit diagram

Is the a good positive feed?

Is there a good engine earth?

Is there a switching feed that can provide sufficient power to operate the solenoid ?

Directly power the switching solenoid feed terminal, what happens? Don't mess on until you've tried this to check the very basic starting system, if this works then check the signal to the starter?

 

[hussnain]

Plain brown wire from ignition switch goes straight to starter try a direct feed to it to see if it cranks? Do this ignition off.
Where does the click sound come from, inside the car or under bonnet?

How would you go about doing a direct feed to the starter? Do I just put 1 side of a jump lead to the power on the battery and the other side of the jump lead to the power pole on the starter motor? My starter motor only has 1 pole where 2 wires are connected too. Do I just have to run a jump lead wire from battery positive to the pole on the starter motor with the ignition off? Guessing this would be called "direct feed".

Click is coming from the fuse box under the bonnet.

Thanks.

 

[hussnain]

A Haynes manual might help or a auto electrician?
You have checked the engine earth strap?
Have you checked the solenoid brown start signal wire with say a 21w bulb to see if it lights when turned to start?

By the haynes manual I can see the starter connects to the battery, ignition switch and alternator. Will try a direct feed to the starter to see if its not a wiring issue between the starter and battery.

Where exactly is the engine earth strap please?

Thanks.

 

[hussnain]

A Haynes manual might help or a auto electrician?
You have checked the engine earth strap?
Have you checked the solenoid brown start signal wire with say a 21w bulb to see if it lights when turned to start?

On the starter there are 2 wires. Cant tell the colors however 1 is a big ring connector and the other is a smaller ring connector. Looks like the big connector has a smaller wire to it so im guessing this would be the ignition switch wire?

Thanks.

 

[hussnain]

Just the one ECU? New or used?

There is an ignition ECU and a body computer that both hold the key immobiliser code. Both need to agree that the key is acceptable.

A report from Fiat, as in Fiat UK, or as in local Fiat dealer? Did they say why it needed a new ECU?

Often complete sets of both computers, and a key set, from a scrapped car, are available on Ebay. Such as this will make your car electronically assume the identity of the scrapped one, and should then function. Need a set of same spec or above. A lower spec may lose some of the higher spec additions as teh body computer will not know about them.

All it says is "No communication to ECU". I then went on to ebay and bought the ECU (under bonnet) with ignition barrel and fusebox/BSI unit (behind the glovebox) but the car still doesnt crank.

Local fiat dealer, no reason why it needs a new ECU.

Thanks.

 

[hussnain]

It doesn't crank,,,, there's very little it can be going off the circuit diagram

Is the a good positive feed?

Is there a good engine earth?

Is there a switching feed that can provide sufficient power to operate the solenoid ?

Directly power the switching solenoid feed terminal, what happens? Don't mess on until you've tried this to check the very basic starting system, if this works then check the signal to the starter?

A and B are both connected to the same pole on the starter with a black protective cover and a nut. The A feed was a little rusty which I sanded down.

Engine earth I am trying to still confirm where the earth wire is located.

Are you referring the "Switching solenoid feed terminal" to the pole on the starter motor?

 

[portland_bill]

All it says is "No communication to ECU". I then went on to ebay and bought the ECU (under bonnet) with ignition barrel and fusebox/BSI unit (behind the glovebox) but the car still doesnt crank.

Local fiat dealer, no reason why it needs a new ECU.

Thanks.

"No communication to ECU" does not necessarily mean an ECU fault, only that the diagnostic port cannot communicate with it. Could be an ECU fault, or wiring. However, having replaced body computer and fuse box, wiring between should be ok.
Below the windscreen is a chamber that feeds air to the heater. It fills with rainwater if the drains are blocked, then the water spills into the car, often over the body computer. This could be the initial cause.

A and B are both connected to the same pole on the starter with a black protective cover and a nut. The A feed was a little rusty which I sanded down.

Engine earth I am trying to still confirm where the earth wire is located.

Are you referring the "Switching solenoid feed terminal" to the pole on the starter motor?

Starter has a fat cable direct from the battery positive.
Starter has a fat body, and a smaller lump piggybacking on top, which is the solenoid that engages the starter gear with the engine, then connects the fat power lead to the motor to turn it.
There also needs to be a small cable to the solenoid to operate it when the key is turned. This will be to a separate terminal on the solenoid, not the same as the fat wire. The click from the underbonnet fusebox is the relay switching current to that smaller wire. If you connect a wire directly between the battery positive and the small terminal on the solenoid, it should operate the starter.
THIS REQUIRES A LOT OF CARE.
A spark at the battery could result in an explosion of the battery. Batteries give off hydrogen gas, and any loitering will go bang.
If you connect to the battery first, be careful with the other end of teh cable as you feed it to the starter, as it MUST NOT contact anything else on the way. A dead short to earth will cause a big spark, frighten you into letting go, and as it contacts more earths mayhem will ensue. Possible outcomes - battery explodes, wires melt, fires start, you get burnt.

From the battery negative terminal is a fat wire. Follow it from the battery, to the car body and on to the gearbox. That is the earth wire. These are known to corrode internally, so may look good at each end, but not pass the current. Check all connections are clean and tight, and flex it a little to feel for any internal breaks. You can test this by by-passing it. Use a jump lead from the battery negative terminal to the gearbox casing.

If you are uncertain about any of this, get help.

As general advice, don't work on any car unless there are others about, so that help is available if needed.

 

[John202020]

If you are uncertain about any of this, get help.

As general advice, don't work on any car unless there are others about, so that help is available if needed.

I think, it would be advisable for you to get some additional help as stated above, if you're not sure which it seems you're not then don't try, not the advise you may want but good advice non the less?

 

[rallycinq]

have you checked the engine hasn't seized as suggested a few days ago?

D