Technical Engine cuts out….not the normal

[blueheaven]

when engine is at normal running temp at idle the car cuts out…..driving car it does not cut out only at idle when hot….if engine gets a load I.e heater fan put on or lights etc car cuts out….restarts perfect….tried two throttle bodies,new Battery,new alternator,cleaned earths,plugs,MAP sensor,checked the usual ecu broken wires all ok,sprayed for air leaks can’t find any….I am also getting a random non start key not recognised, changed key still does it….dont know if two are linked? I did think crank sensor but thought it would cut out while driving but seems only at hot idle? Ecu faulty?

 

[koalar]

One of the Error codes is low voltage
Fails at idle, when you turn on a fan or lights


I’d start by logging the live data of battery voltage while is in failure mode

Easy to do with the software you are running

 

[varesecrazy]

Hi

Some motors dont run a Cam sensor..

If the Crank sensor gives poor feedback it wont warn of an error

Your Key thing happened to me.. once in 14 years.. I normally let all the 'selftest' of the dash happen before cranking

The time I rushed it , it didnt fire...

 

[blueheaven]

One of the Error codes is low voltage
Fails at idle, when you turn on a fan or lights


I’d start by logging the live data of battery voltage while is in failure mode

Easy to do with the software you are running

If I lose volatge where do I look? Ecu? Ignition? Thanks for the help

 

[blueheaven]

Hi

Some motors dont run a Cam sensor..

If the Crank sensor gives poor feedback it wont warn of an error

Your Key thing happened to me.. once in 14 years.. I normally let all the 'selftest' of the dash happen before cranking

The time I rushed it , it didnt fire...

This engine has a cam sensor…..immobiliser was doing it all the time so I changed the key was all good for first 50 ish starts the. Did it

 

[blueheaven]

I have noticed when warm from idle if I very quickly press to full brittle engine dies….instantly starts up no priming of fuel etc….think it’s losing its trigger voltage ecu?

 

[koalar]

If I lose volatge where do I look? Ecu? Ignition? Thanks for the help

Let try and diagnose the problem

What happens to the volts when you rev the car

It’s very easy to log in Delphi ds150

Just plot the revs and volts

 

[blueheaven]

Let try and diagnose the problem

What happens to the volts when you rev the car

It’s very easy to log in Delphi ds150

Just plot the revs and volts

When I checked with volt meter it was 13.9 volts so I changed alternator now got 14.2….when revs Go up it goes up slightly to 14.3

 

[blueheaven]

I plugged in vagcom obd to see what that came up with…also got D600 …..and D601 or D602 can’t remember

 

[koalar]

When I checked with volt meter it was 13.9 volts so I changed alternator now got 14.2….when revs Go up it goes up slightly to 14.3

Perfectly normal now

 

[koalar]

I plugged in vagcom obd to see what that came up with…also got D600 …..and D601 or D602 can’t remember

D and U errors are the same
D600 is just the hexadecimal version


An occasional U16** or U17** isn’t unknown and may or may not be diagnostic useful

 

[koalar]

Does the car still cut out if you put the heater blower on?

 

[blueheaven]

Does the car still cut out if you put the heater blower on?

Yes….and it lights are on….any load it cuts out…..idles at 760rpm….tried raising it to 950 for a test…..still did it…..may try a crank sensor but thought it would do that not just at idle

 

[koalar]

When hot could be a crank sensor
When the revs rise could be a crank sensor


But adding an electrical load shouldn’t be a crank sensor. Should be power or earth


What happens if you connect to another car with jump leads. Does it still cut out when an electrical load is added

 

[blueheaven]

When hot could be a crank sensor
When the revs rise could be a crank sensor


But adding an electrical load shouldn’t be a crank sensor. Should be power or earth


What happens if you connect to another car with jump leads. Does it still cut out when an electrical load is added

Next thing to try tommorow is amother Earth with a jump lead….then will give added power supply a go

 

[blueheaven]

Like to update as to help others in future……always go with gut feeling…..car had a new Delphi crank sensor few weeks ago….it was failing when hot!….. new genuine crank sensor sorted problem….get genuine! Thanks for the help

 

[blueheaven]

When hot could be a crank sensor
When the revs rise could be a crank sensor


But adding an electrical load shouldn’t be a crank sensor. Should be power or earth


What happens if you connect to another car with jump leads. Does it still cut out when an electrical load is added

Agree that’s why I didn’t change it…..but my gut was telling me change it!….new genuine sensor cured it ….weird!

 

[DaveMcT]

Failing crank sensors generally go open circuit when hot. The ECU does not log an error because the same thing happens when the engine stops turning. Stalling our 1.2 just requires a restart. Stalling the 100HP throws up "engine speed too low" on the info panel. So some ECUs can tell when its stalled, but it's not an error state so nothing will be logged.

 

[koalar]

Still don’t understand why turning the lights on causes the engine to stop

And the fault is a crank sensor

 

[DaveMcT]

Still don’t understand why turning the lights on causes the engine to stop

And the fault is a crank sensor

More than one problem going on. Possibly a cracked alternator thats close to seizing up. They charge fine until they lock up and snap the accessory drive belt.