Disabling fuel pump

[NewDan]

Hey guys, is it possible to disable the fuel pump but still run on lpg. I have a fuel leak when the system is under pressure and will have a fair drive to the mechanic. Is it just a matter of pulling a fuel pump relay or something like that. I have an aftermarket tank on the GQ and cant get to the pump without pulling the tank out.

[patch697]

Hey guys, is it possible to disable the fuel pump but still run on lpg. I have a fuel leak when the system is under pressure and will have a fair drive to the mechanic. Is it just a matter of pulling a fuel pump relay or something like that. I have an aftermarket tank on the GQ and cant get to the pump without pulling the tank out.

Just so Im sure on what to advise here, is it carby or injected?

[NewDan]

It's a 4.2 Efi patch

[patch697]

It's a 4.2 Efi patch

Hmmm that can make this a bit trickier being an EFI..

A lot LPG systems fitted to EFI engines require the fuel to be running as they start on fuel then switch themselves to LPG once they start, & as is the case 99% of the time even if yours has not got this setup, you will more then likely find the LPG system itself is powered of the factory fuel pump relay as they do the same thing as a stand alone Gas safety switch which makes it easy to utilize as a power source . So it may be the case that if you pull the fuel pump relay or fuse you may shut your Gas off as well...

Without seeing it first hand its a hard one to call but it maybe easier to fix the fuel leak itself then to power down the fuel system

Hopefully Yendor spots this & comes up with a really easy way around it but thats about all I can think of.

[Yendor]

I would try removing the fuel pump fuse and see if it runs on LPG.

Some LPG system also start on petrol and then switch over to LPG, so you might need to get the vehicle running (if it's safe to do so) and then remove the fuse.

If the vehicle doesn't run on LPG with this fuse removed, another option is, when they removed the original fuel tank from the rear of the vehicle and installed the LPG tank there they would of more then likely extended the original fuel pump wiring and run it to the new fuel tank.

If you remove the fuel tank inspection cover in the rear of the vehicle you may be able to see where they have extended the harness and you can just disconnect it there.

Another option is to get someone like ENZED out to your place to repair the hose.

[patch697]

I would try removing the fuel pump fuse and see if it runs on LPG.

Some LPG system also start on petrol and then switch over to LPG, so you might need to get the vehicle running (if it's safe to do so) and then remove the fuse.

If the vehicle doesn't run on LPG with this fuse removed, another option is, when they removed the original fuel tank from the rear of the vehicle and installed the LPG tank there they would of more then likely extended the original fuel pump wiring and run it to the new fuel tank.

If you remove the fuel tank inspection cover in the rear of the vehicle you may be able to see where they have extended the harness and you can just disconnect it there.

Another option is to get someone like ENZED out to your place to repair the hose.

Gee Rod, You could have chimed in a bit earlier & saved me all that bloody typing........hahahahahah

[NewDan]

Thanks for all your help guys Ill try that in the morning when its light. It had the tank out last week to have a new fuel pump put in and been smelling petrol all week then today I saw the dripping. Problem with enzed is Im suspecting that the leak is coming from the connection at the top of the tank that I cant get access to without the tank removed. Unfortunatly the drive from my home no 1 in melbourne to my home no 2 in St Arnaud is about 300k and didn't fancy a petrol drip for that long. This better be a waranty job lol. Dan

[Yendor]

Gee Rod, You could have chimed in a bit earlier & saved me all that bloody typing........hahahahahah

Sorry boss, I was in the middle of cooking dinner and you had it covered anyway.

[Yendor]

Thanks for all your help guys Ill try that in the morning when its light. It had the tank out last week to have a new fuel pump put in and been smelling petrol all week then today I saw the dripping. Problem with enzed is Im suspecting that the leak is coming from the connection at the top of the tank that I cant get access to without the tank removed. Unfortunatly the drive from my home no 1 in melbourne to my home no 2 in St Arnaud is about 300k and didn't fancy a petrol drip for that long. This better be a waranty job lol. Dan

No worries Dan, it sounds like it should be covered under warranty.

Let us know how you get on.

Cheers Rodney

[rusty_nail]

Why don't you just empty the petrol out and run it on LPG? Sorry if this idea is flawed, but it's a laymans idea...


Tappin

[Yendor]

If you run a pump dry for a prolonged period you can kill it.

[rusty_nail]

Right, there you go. My LPG system is pretty ancient but I have a 3 way switch where everything is manually controlled, I don't have to and rarely do, use petty


Tappin

[Yendor]

I thought it was actually a legal requirement when the LPG system is installed and the system is running on LPG the fuel pump had to be switched off.

On the patrols this doesn't seem to be the case, they only seem to cut the power to the injectors.

[rusty_nail]

My system is ages old. Things may have changed since mine was done but my system runs through an impco vacuum pump and there is a manual switch on the dash. It's the second patrol I have owned with the same system.


Tappin

[patch697]

I thought it was actually a legal requirement when the LPG system is installed and the system is running on LPG the fuel pump had to be switched off.

On the patrols this doesn't seem to be the case, they only seem to cut the power to the injectors.

I'm 99% sure in Vic its not a requirement mate.... Its by no means a hard one to sort out even with the ULP start systems but everything I've worked on for years has just had a relay on the injectors.

[Yendor]

I'm 99% sure in Vic its not a requirement mate.... Its by no means a hard one to sort out even with the ULP start systems but everything I've worked on for years has just had a relay on the injectors.

Yeah it just seems strange.

You can be driving around running on LPG and if one of your petrol lines ruptures there is nothing that will stop the fuel from just pumping out.

[patch697]

Yeah it just seems strange.

You can be driving around running on LPG and if one of your petrol lines ruptures there is nothing that will stop the fuel from just pumping out.

Agreed.... & considering how cheap & easy it would be to have it switchable I'm as surprised as you are that its not a standard requirement.

Back in the day when I was racing, we used to run a pressure switch on the fuel line so if the pressure dropped it cut the ignition to save it from having a big lean out & destroying the engine & even that cost all of about $10

Not something you'd need set up in this situation but not an expensive fix in any case considering the huge safety implications.

[NewDan]

Hey Yendor, just wanted to let you know you were spot on, opened the cover in the back and found where they extended the wiring, it was just a matter of undoing the connector and now it runs on gas with no drips from the fuel tank, you saved my arse and something tells me you have the knowing of a lot of things. How do I become a forum sponsor and support this site with a few $$$. Dan

[patch697]

Hey Yendor, just wanted to let you know you were spot on, opened the cover in the back and found where they extended the wiring, it was just a matter of undoing the connector and now it runs on gas with no drips from the fuel tank, you saved my arse and something tells me you have the knowing of a lot of things. How do I become a forum sponsor and support this site with a few $$$. Dan

This link has all the info you need to become a forum sponsor

http://www.nissanpatrol.com.au/forums/showthread.php?14549-Forum-Sponsorship-Renewal-2012-2013

[Yendor]

That's great news Dan.

Hopefully the mechanic can fix the fuel leak for you (at no charge).