2018 transporter crank no start

[Clay]

Good afternoon
This van has had head gasket change and now wont start,
I've aquired the job but cant see why it wont fire,
only fault code i have is for a nox sensor but woudnt of thought this would stop it starting,
the van will run on easy start until you stop spraying,
thanks for any input,
also should the injector have a 12v feed at ingnition on?

 

[mmi]

Based on the logs all looks good:
- good fuel pressure
- ECU commands injectors to fire

Was it running before head gasket job?
I guess the injectors actually don't burst fuel. Can you smell diesel after cranking the engine?
Did you bleed the fuel system?

Post in thread '[T6_measured] 01-Engine - Built-in test for Transfer fuel pump'

16 Jan 2024

Finally at 6 years VW agreed to replace fuel filter. VW garage tool ODIS uses the procedures below to bleed the the new filter.

Fuel filter bleeding​

(1) Run the pump for 60 seconds:​

VCDS > Select > Engine > Basic Settings > IDE00459-Test of transfer fuel pump​

(2) followed by 30 seconds of cyclic run of the pump​

VCDS >Select > Engine > Output test > Fuel pump electronics​

That's all - start the engine - it starts up immediately - check for leaks

• mmi

• 

 

[Clay]

Yes it was running and overheated,
If i put a test light on the injector plug i get no activity, and can only measure 2.5v,
Other weird reading with ths van, i disconected the fuel presure sensor and got a fault “short to possitive” is this right also i took fuel pressure sensor out of cr and plugged the sensor back in cranked the engine and got a pressure reading, but from where?
Should there be 12v at injectors with ignition on?
What sensors does the ecu need to see to run the engine? Fuel pressure and crank signal
I getting confused with this van and seem to be going round in circles any help or direction will be greatly appreciated

 

[Clay]

Based on the logs all looks good:
- good fuel pressure
- ECU commands injectors to fire

Was it running before head gasket job?
I guess the injectors actually don't burst fuel. Can you smell diesel after cranking the engine?
Did you bleed the fuel system?

Post in thread '[T6_measured] 01-Engine - Built-in test for Transfer fuel pump'

16 Jan 2024

Finally at 6 years VW agreed to replace fuel filter. VW garage tool ODIS uses the procedures below to bleed the the new filter.

Fuel filter bleeding​

(1) Run the pump for 60 seconds:​

VCDS > Select > Engine > Basic Settings > IDE00459-Test of transfer fuel pump​

(2) followed by 30 seconds of cyclic run of the pump​

VCDS >Select > Engine > Output test > Fuel pump electronics​

That's all - start the engine - it starts up immediately - check for leaks

• mmi

• 

I've carried out the intial fueling, and i cant smell any fuel after cranking

 

[mmi]

If i put a test light on the injector plug i get no activity

Engine off, or while cranking?
What do mean - the plug is unplugged thus measuring connector's ECU side of pins without injector?
Test light - what's that?

and can only measure 2.5v,

Measure where - across the injector wires, or across injector wire and ground? Engine off, or while cranked?

Should there be 12v at injectors with ignition on?

I don't think so - the injectors are fired only when engine is cranked/running.

i disconected the fuel presure sensor and got a fault “short to possitive” is this right

Sounds correct

also i took fuel pressure sensor out of cr and plugged the sensor back in

Do you mean sensor was not in fuel rail - and thus shouldn't see the pressure?

 

[Clay]

Based on the logs all looks good:
- good fuel pressure
- ECU commands injectors to fire

Was it running before head gasket job?
I guess the injectors actually don't burst fuel. Can you smell diesel after cranking the engine?
Did you bleed the fuel system?

Post in thread '[T6_measured] 01-Engine - Built-in test for Transfer fuel pump'

16 Jan 2024

Finally at 6 years VW agreed to replace fuel filter. VW garage tool ODIS uses the procedures below to bleed the the new filter.

Fuel filter bleeding​

(1) Run the pump for 60 seconds:​

VCDS > Select > Engine > Basic Settings > IDE00459-Test of transfer fuel pump​

(2) followed by 30 seconds of cyclic run of the pump​

VCDS >Select > Engine > Output test > Fuel pump electronics​

That's all - start the engine - it starts up immediately - check for leaks

• mmi

• 

I've carried out the intial fueling, and i cant smell any fuel after

Engine off, or while cranking?
What do mean - the plug is unplugged thus measuring connector's ECU side of pins without injector?
Test light - what's that?


Measure where - across the injector wires, or across injector wire and ground? Engine off, or while cranked?


I don't think so - the injectors are fired only when engine is cranked/running.


Sounds correct


Do you mean sensor was not in fuel rail - and thus shouldn't see the pressure?

Thanks for reply, i was checking for a 12v feed to injector with key on not cranking ,
The pressure was plugged into its connector but not fitted into the rail,
Im back with the van tommorow so i go through it all again,
Only part of the bleeding process you showed me i havent done yet is the “test fuel pump electronics” part what does that do ? Thanks

 

[mmi]

i was checking for a 12v feed to injector with key on not cranking ,

I think there won't be any feed with ignition on only.

The pressure was plugged into its connector but not fitted into the rail,

got a pressure reading, but from where?

Probably just a calculated - "should be" - value. A kind of emergency mode to run engine even without fuel pressure sensor.

There is also raw value available from the fuel pressure sensor (channel IDE07819). However, it's in Volts so needs conversion.

the “test fuel pump electronics” part what does that do ?

It just runs the fuel lift pump in cycles: 2 seconds ON, 2 seconds OFF.

 

[Clay]

Good afternoon
Iv tried the fuel bleed process several times now,
Im getting fuel pressure and can see the ecu activating the injectors but still no go,
When i put a 12v noid light in the injector plug i have no activity when cranking even though the ecu is showing it should be working,
Any idear what fuse or relay powers the injectors via ecu?
Many thanks

 

[mmi]

When i put a 12v noid light in the injector plug i have no activity when cranking

To capture injection pulses a proper measuring equipment e.g. oscilloscope is needed. The main injection pulse lasts only 2 milliseconds, and the following other two bursts are about 0.5 milliseconds each - thus total of 3 milliseconds. When cranking the each cylinder is fired about once per second so it's such a tiny moment when the pulse can be seen.

Any idear what fuse or relay powers the injectors via ecu?

Well, if you are suspecting ECU not firing the injectors - have you tried unplugging electrical connector of an injector - and verify if any fault codes arise.
Sorry, I don't the fuse - but as long there are no related fault codes I'm fairly confident it's not a fuse issue.

 

[RedUn]

Good afternoon
Iv tried the fuel bleed process several times now,
Im getting fuel pressure and can see the ecu activating the injectors but still no go,
When i put a 12v noid light in the injector plug i have no activity when cranking even though the ecu is showing it should be working,
Any idear what fuse or relay powers the injectors via ecu?
Many thanks

I managed the same on my van after messing with something, can't remember what. Either way, fuses down below the gear lever, middle row I think, check they are all good in the right place. Had me stumped for a few hours when I did it, thought I'd bolloxed the immobiliser!

Fingers crossed solves for you.

 

[Clay]

Fise buy the starter 5a is starter inhibitor relay that ones ok,

 

[Clay]

On other van i can see noid light flash when connectd to injector plug on this van i cant,
When injector plug is disconnected it will set a code for injector,
What does fuse sb20 run? I cant trace it properly on wiring diagram ?

 

[Clay]

Good morning
Update on this poxy van,
After some head scratching and scoping injectors i could see a signal to injectors, wouldnt light up a noid light though, so to mmi you were correct, with this now confirmed i sent injectors off to mate to be test and confirmed they were seized, now how he did unsieze them and there back in van bled up and motor now running, for how long i dont no,
Anyway thankyou for all youre input