Crank no start...but then does...

Just an idea here. I had an issue similar to yours years ago on a Fiesta. It turned out it was a loose earth from the engine to the body. It would randomly fail to start either from cold or from hot. Luckily enough Fiesta engines are small and was easily found and cured by chance. It bugged me for weeks!!! If you've had a new engine there could be a wire somewhere thats worked loose??? Its an easy check.
The main engine earth strap on the left has been a known problem and will documented on here.
 
Just an idea here. I had an issue similar to yours years ago on a Fiesta. It turned out it was a loose earth from the engine to the body. It would randomly fail to start either from cold or from hot. Luckily enough Fiesta engines are small and was easily found and cured by chance. It bugged me for weeks!!! If you've had a new engine there could be a wire somewhere thats worked loose??? Its an easy check.
Could easily be something like that, yesterday was a damp day so maybe some moisture making it worse

Good suggestion thank you @JDC
 
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Possibly one of the red connector wires?


What are you thinking there @Dellmassive maybe a damaged wire?
 
Just an idea here. I had an issue similar to yours years ago on a Fiesta. It turned out it was a loose earth from the engine to the body. It would randomly fail to start either from cold or from hot. Luckily enough Fiesta engines are small and was easily found and cured by chance. It bugged me for weeks!!! If you've had a new engine there could be a wire somewhere thats worked loose??? Its an easy check.
But then it wouldn’t crank. There’s no issue with the engine turning, it’s just not starting.
 
But then it wouldn’t crank. There’s no issue with the engine turning, it’s just not starting.
Good point

A duff earth somewhere else could be an issue I guess or possibly some moisture sat somewhere it shouldn't.

I can't say I've ever heard one of these turn over with no diesel present so my description of it sounding like it had no compression might just be what it would sound like with no fuel.
It was like it wasn't churning over fully, plenty of juice from the starter but not the expected resistance
 
What are you thinking there @Dellmassive maybe a damaged wire?
Well,

@DXX mentioned about using a T pin to probe the wire for the lift pump.

You might have ready access to the wires of they are in that connector...

I never got around to completing three list of words and they're functions.
 
Good point

A duff earth somewhere else could be an issue I guess or possibly some moisture sat somewhere it shouldn't.

I can't say I've ever heard one of these turn over with no diesel present so my description of it sounding like it had no compression might just be what it would sound like with no fuel.
It was like it wasn't churning over fully, plenty of juice from the starter but not the expected resistance
I don’t think moisture is a factor, pure water doesn’t conduct electricity and all of the systems are fused.
 
Well,

@DXX mentioned about using a T pin to probe the wire for the lift pump.

You might have ready access to the wires of they are in that connector...

I never got around to completing three list of words and they're functions.
You've got me thinking possibly something is loose or the fairly newly installed seat base battery is sat on something it shouldn't be. You'd think if something was loose it would stay loose though and it wouldn't have started again but I never underestimate how annoyingly stupid an electrical fault can be
 
Well,

@DXX mentioned about using a T pin to probe the wire for the lift pump.

You might have ready access to the wires of they are in that connector...

I never got around to completing three list of words and they're functions.
What I suggested is fitting a pressure gauge in the fuel line (engine compartment).
I guess there’s no harm in monitoring the lift pump voltage but that’s no guarantee the pump is running.
 
You've got me thinking possibly something is loose or the fairly newly installed seat base battery is sat on something it shouldn't be. You'd think if something was loose it would stay loose though and it wouldn't have started again but I never underestimate how annoyingly stupid an electrical fault can be
Many faults stem from the last place a human was involved!
Always retrace your steps, a good place to check first.
 
I don’t think moisture is a factor, pure water doesn’t conduct electricity and all of the systems are fused.
Fair one. Just trying to rule out what's changed.
Soaking wet day yesterday with 2 instances of the fault, vs a dry day and no sniff of a no start
 
Many faults stem from the last place a human was involved!
Always retrace your steps, a good place to check first.
Been long enough for it to have showed by now but worth a look.
Had it done it immediately afterwards I'd be onto something
 
Have you measured the battery voltage when cranking?
I had a battery that was cranking fine but was defective.
 
Have you measured the battery voltage when cranking?
I had a battery that was cranking fine but was defective.
I haven't to be fair. Meant to put the battery tester on it today
It's had a new battery about 8 months ago but ill give it a check
 
I've got a topdon battery tester that does a crank check and I know what it was doing when the battery was new so it's a good comparison albeit not expecting any issues
 
Still seems weird that its reset something by connecting to a diagnostic tool but maybe that makes sense to someone?
I cannot think how connecting the scanner would "fix" the issue, but maybe @mmi has an opinion on this.
Can't think anything how connecting a scanner would affect engine - T6 even has a gateway between OBD socket and actual CANbus.

2017 CXEB (had a new engine 15k ago)
before my ownership I'm afraid.
How long is your ownership? How many miles?
Any backstory before/during your ownership re EGR, DPF, AdBlue?

Please check exhaust tailpipe - is it sooty?

Any chance you could make a couple of engine blockmaps under varying conditions = while driving - by using VCDS "Repeats" option.
Please keep cabin heater blower at speed 2 or above - to eliminate "smart charging".

1761163696099.webp

Each blockmap takes 1 minute 6 seconds - thus adjust "repeats" according your journey. Minimum of 20 minutes would be nice. Ideally then 1-2 blockmaps hot engine idling at the end of the journey.
 
Can't think anything how connecting a scanner would affect engine - T6 even has a gateway between OBD socket and actual CANbus.



How long is your ownership? How many miles?
Any backstory before/during your ownership re EGR, DPF, AdBlue?

Please check exhaust tailpipe - is it sooty?

Any chance you could make a couple of engine blockmaps under varying conditions = while driving - by using VCDS "Repeats" option.
Please keep cabin heater blower at speed 2 or above - to eliminate "smart charging".

View attachment 306995

Each blockmap takes 1 minute 6 seconds - thus adjust "repeats" according your journey. Minimum of 20 minutes would be nice. Ideally then 1-2 blockmaps hot engine idling at the end of the journey.
I've had it a year. Very few miles around 1500. The odd longer journey long enough to show an underlying issue.
The warranty engine replacement was a result of the excessive oil usage CXEB plague. DPF was replaced together with turbo pack and injectors.

Yep I agree it's a stretch on the link with connecting a scan tool. First time I could put down to coincidence, but 2nd time I'd left it longer and it just wasn't starting. As soon as I connected the tool, it started on the button. Could still be a coincidence but the timing was stark.

No issues with after treatment systems. It's had an EGR and AdBlue delete when it got a remap 6 months ago and run flawlessly since.
I did consider sticking it back to stock, it crossed my mind an AdBlue no start would look like this but it's obviously not counting down so shouldn't be anything to do with it.
Stock is still an easy option but kind of hoped the fault would be present to actually start ruling stuff out.

I haven't checked the DPF stats for a couple of months but it was regenning as expected. Worth checking distance since last regen and pressures?

Can happily do some blockmaps tomorrow 👍🏼

Thanks @mmi
 
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