Anyone know what the pressure the 2.7 low pressure pump runs at?

[nudibranches]

Okay I've had a look at the low pressure pump and it actually looks okay. Does anyone know what pressure they are supposed to run at?

I've been told 2 bar but also 0.2 bar?

Mine is running at 0.2bar.

Many thanks.

[JeanLuke]

2 bar sounds high for what is effectively a fuel forwarding pump - that's around 30psi. I would have expected more like 5-7 psi, which is around 0.2 bar or a little over.

How did you measure yours?

[nudibranches]

thanks. Bloke working on it with me measured it. High pressure pump is fine but we were told by "one diesel expert" that the LP pump should be 2 bar and another "diesel expert" that it should be .2 bar.

Car cranks doesn't start. New injectors, new sensors, new fuel lines. Next time Toyota!!!!!

[JeanLuke]

I won't pretend to be a "diesel expert" but I have started to find my way around the WG.

It won't start until the ECU sees the fuel rail pressure hit a threshold - I think around 200 or 250 bar. You can read the rail pressure with WJdiag Pro. I recommend doing this check. It will tell you what the ECU *thinks* the rail pressure is, which may not be what it *actually* is if you have a wiring fault.

You can also read fault codes. I'd expect to see some of it's not firing.

[bodgie]

What is the car not doing nudibranches?

I'd expect the pressure of the fuel rail need to be in the 250 bar range before the car will start.

Even if the lift pump is providing low pressure, I'd expect the engine should still start, but have fuel starvation issues at higher RPM.


Jason

[nudibranches]

Thanks guys for the replies. It's simply not starting. It cranks and won't fire. If we hold a rag soaked with fuel over the intake it does. All new injectors etc. As mentioned we were told the LP pump needs to be putting out 2 bar by one "expert" and then another said it was 0.2bar. Also these pumps just don't lift fuel, they pre-prime the HP pump. No codes. ECU has been checked and is fine. 2 tonne paper weight at present.

[bodgie]

Originally Posted by nudibranches

Thanks guys for the replies. It's simply not starting. It cranks and won't fire. If we hold a rag soaked with fuel over the intake it does. All new injectors etc. As mentioned we were told the LP pump needs to be putting out 2 bar by one "expert" and then another said it was 0.2bar. Also these pumps just don't lift fuel, they pre-prime the HP pump. No codes. ECU has been checked and is fine. 2 tonne paper weight at present.

Been there, done that. My problem ended up being a bad injector or two.

The problem was a one or two injectors had excessive leak-back and this informed the fuel pressure regulator which then told the ECU, Houston we have a problem which shutdown fuel pressure delivery. Essentially it all stopped there, sometimes it would fire and then stop, sometimes it would crank forever.

A quick way to see if this is the problem is to disconnect the fuel return line from the injectors or remove it from the pressure regulator. This will remove the feedback loop and the engine may start. If it does you're more than likely up for a new injector or two, very possibly number 4/5.

Perform a leak-back test to confirm.

As for experts, some are good, others not so much. Working out which one you have is the challenge.

HTH,

Jason