Engine cut out and wont start now.

[mmi]

Here is where we are at for some reason we can not clear the fault code

P056200 System Voltage Low Voltage

That indicates that something is still wrong.

Couuld this be the reason why it's not starting, that the ECU is not getting enough power or thinks its not getting enough voltage even though it is.

It's a possibility - and needs to be rectified.

It's weird because these are the values that are being read

Around the ECU there are almost 50 measurement values which have "voltage" in their label.

Can you make a full channel map of the ECU
How-to:

Won’t start [Resolved]

T6 204 diesel. Van was used on a long drive and then a trip to the shops. It was left 5 mins and then wouldn’t start. Turns over but doesn’t fire. no fault codes. There was a slight burning smell when I parked up and it looks as if the front egr pipe has a crack, rear one has already been...

www.t6forum.com

 

[rudeboyraz]

Today I took off the solenoid on the HPFP to see if there was any swarf in the fuel. The garage that I'm using is adamant that we will need a replacement ECU to rule that out.

 

[rudeboyraz]

Certainly wouldn't hurt to get also full copy of engine's measurement values.

VCDS -> Applications -> Controller Channel Map ->
View attachment 125797

Tick/fill boxes as above and hit Go.
VCDS flashes screens for a moment (when finished hit "Done, Go Back") and there will be file blockmap-01-... in folder C:\Ross-Tech\VCDS\Logs\....

That indicates that something is still wrong.



It's a possibility - and needs to be rectified.


Around the ECU there are almost 50 measurement values which have "voltage" in their label.

Can you make a full channel map of the ECU
How-to:

Won’t start [Resolved]

T6 204 diesel. Van was used on a long drive and then a trip to the shops. It was left 5 mins and then wouldn’t start. Turns over but doesn’t fire. no fault codes. There was a slight burning smell when I parked up and it looks as if the front egr pipe has a crack, rear one has already been...

www.t6forum.com

I will be trying this on Monday thank you so much for your input.

 

[Phil_j89]

Today I took off the solenoid on the HPFP to see if there was any swarf in the fuel. The garage that I'm using is adamant that we will need a replacement ECU to rule that out.

View attachment 203298

Its on the front of the pump, the part you remove to check the lobe - not that on top.

 

[rudeboyraz]

Just an update after speaking to a few people they suggested getting the injectors tested, I had them tested and 2 failed so had them reconditioned. Put them back in and it still doesn't start. Garage is suggesting change HPFP as there is no fuel pressure. I really don't know who to trust anymore and I'm without a bus which I need for work. Do I take the punt and change the HPFP, I can get a second hand one for £350.

 

[rudeboyraz]

So this was the culprit anyone hazard a guess.

 

[DXX]

View attachment 205352

So this was the culprit anyone hazard a guess.

Its on the front of the pump, the part you remove to check the lobe - not that on top.

I’d say that @Phil_j89 was on the money.

 

[Phil_j89]

Ah, not the first time I’ve seen that!

Usually either the spring snaps, or the pump love is damaged.

You should be good to go with a replacement hpfp.

 

[DXX]

Does anybody know if the double plunger pump variant is liable to fail in the same way?
Not saying its the case here but surely mapping and engine for a power increase by increasing fuel pressure is going to add load to the cam and follower.

 

[rudeboyraz]

For what it takes, time wise.. I'd be taking the valve off the front of the pump (that the union is screwed onto, that goes to the fuel rail) and checking the spring isn't snapped, or that the lobe inside the pump isn't damaged / scored. You will have to a roller / follower once the valve is removed to see the lobe.

We've had a good number of running faults / no pre warning cut outs, that have been caused by HPFP failure.

Ah, not the first time I’ve seen that!

Usually either the spring snaps, or the pump love is damaged.

You should be good to go with a replacement hpfp.

Thank you for the advice I didn't know how to quote you before to thank you. The HPFP was my original gut feeling because it felt like it had run out of fuel I even questioned whether the gauge was right and put 20 litres in it. I can't believe how brittle these springs must be to snap in three at just over 100k my last 1.9 T5 had done 400k.

 

[rudeboyraz]

So an update I got the HPFP back from refurb and installed today. Its now struggles but eventually starts and is really rough then cuts out after a few seconds.

 

[DXX]

So an update I got the HPFP back from refurb and installed today. Its now struggles but eventually starts and is really rough then cuts out after a few seconds.

There is the possibility that the damaged HPFP dumped debris into the injectors. Normally a damaged HP pump contaminates everything onward including the leak off line and fuel tank. Basically the whole fuel system, see procedure in VW manual.

 

[Phil_j89]

They’re usually ok if it’s just the spring that has snapped, it’s when the lobe on the pump is damaged that you get swarf in the system.

Although you’d be well off dropping the tank to check for swarf, given the amount of times it will have been tried to be started - this could well cause swarf with it not being lubricated properly without diesel.

 

[rudeboyraz]

I don't think they have primed the system properly. Is there a certain way of doing it?

 

[rudeboyraz]

Pump has been primed still no good they think its the injectors but im not so sure they were reconditioned before the pump. Is there certain readings I should be looking for to rule out injectors?

 

[DXX]

Pump has been primed still no good they think its the injectors but im not so sure they were reconditioned before the pump. Is there certain readings I should be looking for to rule out injectors?

Leak off rate.
If the current injectors were in place with a damaged pump they may also be damaged.

 

[rudeboyraz]

Leak off rate.
If the current injectors were in place with a damaged pump they may also be damaged.

I understand what you mean but there was no visible swaf and with the old pump no fuel was going to the rail as the spring had snapped inside the HPFP

 

[DXX]

I understand what you mean but there was no visible swaf and with the old pump no fuel was going to the rail as the spring had snapped inside the HPFP

Micron clearances in injectors and fuel pumps, should be serviced and tested in a ‘clean room’.
Assuming you have fuel under correct pressure to the injectors it‘s possible to check for excessive leak off by disconnecting the leak line and measuring.

 

[DXX]

@rudeboyraz what was the outcome?