Fuel Rail Pressure at Cranking Speed

[Hodge]

I should be doing the CSR in this vehicle this year. Damn. I bought a diesel because I thought it would be good for hundreds of thousands of KM's, it's only done 98,000. It's not like I haven't been maintaining it either.

This my friend is the nature of the Zd30. They are absolute puss ...

In relation to your cranking faster when battery is charged... I'm just brainstorming here.
Battery charged, engine cranks over faster ... in turn pump creates more pressure, car starts ??
Battery not full, cranks slower, pump cannot pump enough fuel due to slow cranking ?? I mean the cranking speed may not be that much different but it just may be enough for the pump to be fussy ? I hope I'm wrong for your sake, but, it's worth looking at ?

[2HQueues]

Hi Hodge.

Yes, the thought that the cranking speed might be right on the limit crossed my mind too. Fraction under, ECU tells injectors "not enough rail pressure, don't squirt any fuel", fraction over, "OK let's go". I has hoped a new battery would eliminate this suspect, but I will need to put it on the list should the new pressure relief valve not fix the problem.

Thanks for your thoughts Hodge.

[2HQueues]

But now I come to think of it, I've had the battery quite run down in the past, after leaving something on, and it cranked pretty slowly yet still started, so it must be something other than slow cranking speed, or a combination of slow cranking and low rail pressure due to another fault.

[2HQueues]

The solution to my extremely hard to start ZD30DDTi.

FUEL PRESSURE RELIEF VALVE!!!!!

It took about 35 mins to swap over and now it starts like it was brand new. Not a difficult job, you'll need a 17mm combination spanner and something you had add to that for extra leverage, a piece of pipe or a larger open ended spanner which is what I did.

For Bosch rail 0445214112

Part Number 1110010018

I got mine from United Fuel Injection in Perth ph 1800 199 701. Give them a call, they're very helpful and friendly, and will post anywhere in Aus for a small fee. And you know you're getting GENUINE BOSCH. Much cheaper than buying a whole new rail.

http://www.unitedfuel.com.au/

If it wasn't the FPRV the next thing to check would be for leaky injectors.

So if your Nissan Patrol has progressively gotten harder and harder to start then this would be the second thing I'd look at. The first thing to check would be the primer bulb, if the valve in that has gone your diesel will be draining back into the tank. You're Patrol will start easier if you park it up nose down.

Thanks to Rumcajs & Hodge for all your help.