Fuel starvation

Badger · Apr 23, 2021

Puma 2011 Def.

When the truck reaches temperature, the fuel pressure becomes erratic, I lose power and then it conks out.

Before reaching temperature ( 82C ) it'll run with no problems.

VCV replaced with new quality unit

Any thoughts?

Cheers

Wimblowdriver · Apr 23, 2021

VCV - do you mean the fuel metering valve on the fuel pump? If so has it been put through the pump learn procedure, required after replacement?
Getting diagnostic trouble codes will pinpoint the problem, I have the fault code schedules if you can get the DTC's. If you think its temperature related, have a read of the attachment ---

Badger · Apr 24, 2021

Yes on the HP pump.

Relearn was done as well.

I've gone through the manual as well, the Pressure release valve on the HP rail could be an issue but 2 things have stopped me moving and replacing it, one being if it is faulty then fuel pressure would be affected no matter what the temperature of the engine is and secondly, it throws up an engine management light if it goes into fault I believe? Or it should show up on the OBD reader as a fault and yet I get none.

History of the engine is recently had head removed and reconditioned, replaced the coolant and vacuum pump ( all purchased from Turners including engine gaskets and bolts etc )

After the recent issue with the vacuum pump destroying itself, this problem has begun after I replaced the vacuum pump even though everything is back to normal with parts
EGR switched off via ECU.

I'm removing the tune this morning to see if this has any affect on it

Wimblowdriver · Apr 24, 2021

Badger said:
I've gone through the manual as well, the Pressure release valve on the HP rail could be an issue but 2 things have stopped me moving and replacing it, one being if it is faulty then fuel pressure would be affected no matter what the temperature of the engine is and secondly, it throws up an engine management light if it goes into fault I believe? Or it should show up on the OBD reader as a fault and yet I get none.

Bit more info attached. Looks like that once the relief valve "relieves" it is pooped and has to be replaced. At least thats how I read it. Have you got a workshop manual? pages attached in case you don't have one.

Badger · Apr 24, 2021

De tuned and replaced the valve as precautionary measure but it’s still playing up.
I can drive it about town without putting it under stress on the de tune as long as I keep the fuel pressure down, with the tune it’s a lot worse and much more difficult to drive but that’s possibly because it revs much easier

Badger · Apr 24, 2021

Wimblowdriver said:
Bit more info attached. Looks like that once the relief valve "relieves" it is pooped and has to be replaced. At least thats how I read it. Have you got a workshop manual? pages attached in case you don't have one.

I do have it but thank you for posting

Wimblowdriver · Apr 24, 2021

Just a thought - but what makes you think its a fuel pressure problem? And you are getting no engine management light on the dash, is that correct?

Wimblowdriver · Apr 24, 2021

Out of interest, what tool did you use for the pump relearn? In case I need to do mine at some time.

Badger · Apr 25, 2021

I use the GAP IID tool which my tune software from BAS came with.

I've monitored the fuel pressure's using the live values as well as other areas to see if there is any correlation between any of them and the only one showing is the temperature reaching 92C and above is when the issue begins.

I also used the tool to do the vcv relearn and pilot correction

Fuel starvation

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