4.2 efi fuel system.

[kbchez]

Hi has anyone got the fuel system diagram of the 4.2 fuel system . I Can not find one on the net.
My poor old patrol starts like a old diesel with a airleak.

There must be a non return valve or something to keep the fuel at the fuel rail.

I have done head gasget manifold gasgets etc. No vacum leaks now i hope. All injectors çleaned etc.

[dom14]

It's in the manual that you can download from here.

[kbchez]

Thanks dom,
i have downloaded the gq manual but there's nothing about efi.

[Parksy]

Hi Kbchez

I'm trying to work out what you're actually asking.... do you have a vacuum leak somewhere? If so, there are so many points where it could be leaking from. Easiest way to fix this is replace all the lines with new silicon hose. Also a can of wd40 sprayed onto various leak points may help in diagnosing any leaks.

The fuel rail has a pressure regulator at the front which maintains pressure at idle to about 32 psi. When you accelerate or start the engine from a hot start, this pressure will be higher.

[mudnut]

It's in the manual that you can download from here.

It sucked me in too, Dom, but the diagrams are for the TD.

[dom14]

It sucked me in too, Dom, but the diagrams are for the TD.

My bad.

I've got no idea why they would omit the EFI fuel diagrams from the factory manual.
I guess that information is in the supplementary manuals, which are usually pricey.

[dom14]

Hi has anyone got the fuel system diagram of the 4.2 fuel system . I Can not find one on the net.
My poor old patrol starts like a old diesel with a airleak.

There must be a non return valve or something to keep the fuel at the fuel rail.

I have done head gasget manifold gasgets etc. No vacum leaks now i hope. All injectors çleaned etc.

Air leaks/vacuum leaks shouldn't be too hard to detect.
Arm yourself with a spray can of WD40 and spray into the suspected areas while revving the engine, or you can even use water/soap water.

[dom14]

It sucked me in too, Dom, but the diagrams are for the TD.

This post might be of help.
http://www.nissanpatrol.com.au/forums/showthread.php?23925-92-tb42e-fuel-injection-wiring-diagram&p=437523&viewfull=1#post437523

Also section 4 of the Haynes manual, (which is free to download from here) has some information on the TB42e fuel system.

It's in 4B-1 with the title "Fuel and Exhaust systems - Fuel Injected Petrol Engines".

[dom14]

Or buying the "Fuel and exhaust system - EFI systems" of the GQ Patrol factory repair manual supplement can help as well.
Not sure whether it's easy to locate a seller.
But, I know few guys have it in their repair manual arsenal.

[kbchez]

Hi all,
Thanks parksey, i have no vacum air leaks.
Its when starting when cold It starts like a diesil with a air leaky system.

The link to the old posting is very helpful. Because I have removed the lpg from the wagon. Now I need to find the earth relay. I have seen one next to all the other relays under the bonnet. Maybe this one has something to do with the problem.
Is there a none return valve, for the fuel, at the fuel pump. I think its at or in the fuel tank setup.
A real wiring diagram would be helpful. To trace the injector wiring to lpg relay setup.

[dom14]

Hi all,
Thanks parksey, i have no vacum air leaks.
Its when starting when cold It starts like a diesil with a air leaky system.

The link to the old posting is very helpful. Because I have removed the lpg from the wagon. Now I need to find the earth relay. I have seen one next to all the other relays under the bonnet. Maybe this one has something to do with the problem.
Is there a none return valve, for the fuel, at the fuel pump. I think its at or in the fuel tank setup.
A real wiring diagram would be helpful. To trace the injector wiring to lpg relay setup.

Why do you wanna know about the "not return" valve??!!!

There's a non return valve on the fuel line from tank to charcoal canister.
It's installed closer to the tank on that fuel line.
Highly unlikely that has anything to do with the problems you described.

What "earth relay" are referring to???!!!
Why do you need to find it??!!

[kbchez]

Yep i found the injection info in 4.b.section... great reading. A few things to check under the bonnet. The first to check out is the fuel pressure relay. Then undo all the earth leads and clean refit. Bad earths big problems.

[Lucas Bree]

Have you found the drama? Mine also struggles to start cold have to crank it 3 or 4 times before it will actually fire up runs rough as until I give it a stab on the throttle. As soon as it idles I can shut it down and it will start perfectly from then on and doesn't miss a beat. It's a TB42E no gas (never had gas)auto. Any advice please.

[kbchez]

There is a return solinoid from the fuel rail back to the fuel tank. I been told they play up.

[dom14]

There is a return solinoid from the fuel rail back to the fuel tank. I been told they play up.

It is usually the Fuel Pressure Control Valve. In RB30, it's triggered by RPM range(kicks in around 1500 rpm or so).
There's a Engine Revolution Trigger unit under the dash on RB30.
Since carby TB42 comes with a mechanical fuel pump, I'm guessing Fuel Pressure Control Valve may not be as critical as in EFI model or RB30(has electrical fuel pump)?