Z3 Cranks but sometimes does not start.

[bonbon]

Ok - finally changed out the fuel pump. Surprised to find that the pump’s one way valve is fine. So I assume the fault was a weak pump. Perhaps there was not enough pressure to start reliably - but was fine to drive.
All ok now - you learn every day.

 

[the Nefyn cat]

A happy christmas, then.

 

[bonbon]

Next morn - not ok.
What I did learn is that it ain’t over until the fat lady sings. Problem still persisting. Nothing to do with the pump or its return valve. Will continue the search. Cranks - but need to play games for it to start (ps - it’s not the starter either - it was just sorted recently).
Any news bright ideas?!

 

[bonbon]

Ok - this is embarrassing so please nobody take the P.
I did a bit more research (which I seemed to have missed in my search 9+ months ago) and found that vac leaks can cause cold start problems.
Had a closer look at my M44 inlet piping and found a cut on the underside of the smaller pipe that exits the MAF boot. Pics attached.
I’ll know next cold start as I’ll tape it up until I get a replacement pipe. It’s driving me crazy.

 

[bonbon]

The fat lady sang. All sorted. It was the non visible tear in the pipe. ( pic above).
End of a 10 month saga
To be fair - I also removed and cleaned the idle control valve to feel useful. Not sure if or how much it contributed.
May us all have a good year!

 

[the Nefyn cat]

All sorted

Yeah, right.

But there's nothing fundamentally wrong with optimism.