VW T5.1 2.0 CAAC Long Crank / Starting Issues?

[JohnDeere]

Hi

My 2015 T5.1 2.0 CAAC has never been a great starter in the 16 months I have owned it but its got worse in the past few weeks. If often starts the first time, I go out and it fires but I drive down the road 2 miles, engine off and it then struggles to restart, cranks for a good 10 seconds sometimes.

Long story short, went into a garage today and they said no codes coming up but the fuel pressure is all over the place, even with the engine off.

He said the first thing to change is the fuel pressure sensor? I don't mind changing this (haven't had a price yet) but concerned I am going to just throw money at it.

Should the sensor throw a code?

Once it starts, it seems to drive ok as far as I can tell. Idles fine, doesn't cut out or stutter etc. The only symptom is an intermittent long crank.

The long crank happens every journey, its just whether its the first crank or the second etc, ambient temp makes no difference and there is no pattern to it.

Can you test the sensor?
Thanks

 

[JohnDeere]

Update

Have a friend who works for Audi stick his laptop on while it was doing it.

You could see some white smoke coming out while it was cranking, he said this was a symptom of the long crank, dumping fuel into the exhaust.

Reckons the fuel pressure it about 4bar at crank which is plenty to start it and whilst running, the pressure it around what it should be.

Said one of the injector readings was high, showing 2.67mg and the rest were -1 or similar and were compensating for the injector with the high reading to get the overall value from all four to zero.

Said it’s worth changing the fuel pressure regulator first as if this has an issue, it can cause the readings for the injectors to the off. Failing that, it’s a leak down test for the injectors and replace any that are failing.

Reckons it’s worth letting the garage change the fuel pressure sensor Monday for the sake of £95 but he doesn’t think that will fix it.

 

[JohnDeere]

Changed that sensor and made no difference.


Garage who I took it so reckon it could be the HPFP disintegrating and instead of throwing parts at it, they want to remove the pump and check for metal filings!

It runs fine, its just an issue with it turning over.

 

[Benjaminfjkv]

Have the EXACT same issue, i am suspecting a possible missing signal to injector when the issue is present, cause if I use starting fluid, it starts right up.

 

[meza]

Might be worth looking at fuel rail pressure regular too. On the other end of the rail to the sensor.

Mine had a wildly fluctuating fuel pressure and rough idle, and replacing the reg fixed it.

Garage did the fuel metering valve on the HPFP first and it had no effect.

 

[JumpShip]

Is it turning over fast enough ? Ours starting cranking for longer than normal and started dragging the battery down .
Didnt initially sound slow turning over . Took a punt and swapped to starter out ....problem solved .