General Misfire 1 and 4

[Plb121275]

Hi update please help ,my friends fiat 500s intermittent faults not storing in ecu,car cuts out when driving.she plugged in obd scanner when happened straight away and error codes were misfire cylinders 1 and 4.changed plugs,coil pack and leads but same happened again

 

[steveras57]

Hi what age is the car ?how many miles? do you know if the main earth strap has been changed?

 

[Plb121275]

2013 with less than 60,000 miles and don’t know about the earth strap.seen that could be a fault.ecu being off to be tested

 

[steveras57]

Earth strap first to check , then hatch wiring, after that might be worth putting replacement injectors on those cylinders ! i had a rough and lumpy tickover and tried all the electrical stuff first- but it was the injectors that cured it!

 

[Plb121275]

When going over 50mph the car cuts out completely and won’t start again for about 15 minutes

 

[Plb121275]

Where is the hatch wiring? Thanks

 

[steveras57]

Where is the hatch wiring? Thanks

open the boot top left hand corner is a large rubber grommet!- GENTLY! peel it back to check wires inside, often the insulation has broken down and fallen apart exposing bare wires that can touch and cause shorts ,sometimes wires are completely broken( but this usually cause loss of functions and warning lights). more often happens on the hatch side of the grommet(right) rather than the car body side (left) repair kits are available!

 

[Plb121275]

Thank you for your advice,I’ll ask her drop car off tomorrow to check and update you.thanks again

 

[John202020]

Cam belt been done recently?

 

[Plb121275]

It got done just before she bought it in December

 

[steveras57]

The reason John asks about the cam belt is because its VERY easy to get it wrong and if the timing is out by just one tooth then it can cause the symptoms you describe! was the belt done by a Fiat dealer? as small independent garages OFTEN make mistakes many reports of problems on here!.
If it was NOT done by Fiat I would recommend you get it checked by one ASAP!¬.

 

[vexorg]

Do fiat use a wasted spark method? just seems odd that plugs 1 and 4 report a problem as they would be linked in a wasted spark system.

 

[John202020]

It got done just before she bought it in December

If the car was driven " round town " most of the time after the belt was changed, a mis fire problem would 'hide' up until the car was out on the motorway once at speed then the ecu flags up the problem and limp mode

 

[chris3234]

It got done just before she bought it in December

Either been timed wrong or needs phonics wheel relearn my guess