Rough idle help

[Simo5000]

Hi all,

Very new to the forum and Transporter ownership.

Picked up the van on Sunday and on Monday it developed a rough idle which doesn’t go away when warm or after a good drive.

2016 T6 CAAC Bluemotion 140 272k miles. Cambelt and Egr cooler replaced in the last year. Idled perfectly fine on the two visits before purchasing it.

Now it idles really badly. No fault code or light. No smoke (white or blue). Still drives fine, just idles badly. Injectors, hard pipes and fuel rail looks fine. Though the top of the pipe fitting/injector/return furthest from Cambelt is damp but nothing coming out when the engine is on or revving. Have tried to nip it up but is tight. Have read online about the IMV or Fuel rail pressure regulator possibly being an issue. Plugged in my diagnostic tool and the fuel rail pressure is all over the place. See video

What would be the first port of call? I want to check the damp injectors/pipe, Is there a rubber o-ring under there or just metal a compression fitting? Am I good to remove, inspect, reseat? Will it prime by cranking/ignition or do I need vcds?

I’m guessing after that, replace the reg or valve?

Does anyone else have any idea before I start? I don’t have VCDS.

 

[Simo5000]

Thought I’d follow up on this.

Saw that the fuel pressure was everywhere. Cracked an injector and idled perfectly! So decided to bite the bullet and replace the fuel rail pressure sensor and Regulator (Advice from another thread on this forum)

Removed fuel rail, replaced the two units, refitted, used Carista to prime the fuel system, turned it on and it idled poorly (same as before), ran up the revs stationary, still ran rough, but as the manual says, drive the van and reach full throttle. Did that, idles perfectly now. Dont lose hope at the first start, it needs that drive to clear the air out.