Dual Fuel Question

[echnidna]

I know that on duel fuel engines the carbys dry out and the accelerator pump won't work properly if you don't run the engine on petrol regularly.

If you put duel fuel on an efi engine do you need to run them on petrol regularly or doesn't it matter.

Should the efi fuel pump be switched off when running on gas

[journeyman Mick]

Bob,
I have a VP (92?) commodore on Duel fuel. On gas the system automatically starts on petrol, then switches over to gas. I don't know whether r not the petrol pump is turned off, no doubt the gas system has to do all sorts of fancy stuff to fool the engine management system into working. I don't think you need to do any of this stuff, the module takes care of it all.

Mick

[silentC]

What's this duel fuel you're talking about? Pistons at dawn?

:)

[DJ’s Timber]

My '05 Sr Hilux uses petrol to start and automatically changes to gas when water temp reaches 40deg. So on a cold morning the motor warms up abit on petrol first then onto gas or if already warmed up starts on petrol then changes to gas after about 10 seconds.

Some systems change to gas when motor reaches preset rpm after starting.

All depends on which system you install, but most of the EFI cars start on petrol then switch to gas.

Most installers recommend that you do a short run on petrol after every third or fourth tank of gas to lubricate your valves and stop seals and gaskets drying out.

[silentC]

Get it?

Duel = pistols at dawn

Duel = pistols. Fuel = pistons

Pistons at dawn.

See, you mean dual fuel, as in two types of fuel, but you typed duel fuel instead...

Ah forget it :p

[echnidna]

bang

[Gumby]

I had a Falcon XR6 on dual fuel but is was about 12 years ago. It didn't switch over automatically so I was told to run the gas to empty, then run about 30kms on petrol before going back to gas.

[dazzler]

Modern systems will start on petrol and then go to gas.

There is an even modernererer one (gen 3 or something) but I dont know what it does sadly

[Big Shed]

The "moderner" one you may be thinking of is the direct injection system. This doesn't get injection in the air intake but thru the normal petrol injectors. Not cheap but reputedly gives same economy as petrol, although I can't see how as LPG has fewer calories than petrol.
Whereas the conventional system for a Falcon (AUIII) cost $2700 installed, the direct injected system is $3500.

I know it is available for the Falcon/Territory and I think the Landcruiser.

Most LPG systems today don't have to be run on petrol anymore, for instance my daughters' Falcon was converted 2 weeks ago using a Sprint system and their recommendation is that you don't need to run it on petrol.

And of course Fords' dedicated gas system can't be run on petrol:D

[Landseka]

The newer systems available now (not sure now of the name of it) use replacement injectors and the LPG is actually injected into the cylinder as opposed to the more common system which introduces the LPG into the airstream which flows to the inlet manifold & is distributed to the cylinders.

The newer system is supposedly much more efficient but at a considerable greater installation cost


"Snap" Big Shed

[Big Shed]

The newer systems available now (not sure now of the name of it) use replacement injectors and the LPG is actually injected into the cylinder as opposed to the more common system which introduces the LPG into the airstream which flows to the inlet manifold & is distributed to the cylinders.

The newer system is supposedly much more efficient but at a considerable greater installation cost


"Snap" Big Shed

Snap indeed:D

Looked it up and the new system is called multi-point injection Gen 3, whereas the current system is single point injection.
I run an MGA system on a Commodore VX and it works very well, average 8kms/ltr, LPG at present 46.9 here and petrol 124.9. Paid for LPG conversion (pre-Howard generosity) about 15 months ago about $1800, paid for itself in 11 months or 20000k.

[Malibu]

I converted my BA ute to duel-fuel about 6 months ago and used a Prinz brand injection system. Pre-conversion, I was getting around 12 litres/100 and now running mostly on gas, I get around 13.5 to 14 litres/100. A bit heavier on consumption, but considering LPG is 1/3 the price of juice, it's a big saving in $$'s.
It's set in the system software to start on petrol and switch over at 28 degrees, but I usually keep it on petrol when the engine's cold and I'm in traffic for a few km's. Apart from a small power loss, it's been great!
According to the Ford mechanics (who put it in), I don't need to run it on petrol for lubrication, but I do a tank of petrol for about every 10th tank of gas, just to be safe :)

[outback]

We converted our Vx also, thanks to John's generosity. Currently paying around 59.9 for gas, unleaded about 124.9.

As we don't have access to a gas outlet all the time we run it on gas as much as possible, but at times foreced to run on unleaded.

As others have said, it starts on fuel then swaps over, we were told that is all that's needed, but I'm happy to see a little extra fuel used to keep things lubed.

[Jim Carroll]

Just checking on prices quoted on the better system.

I have been quoted $4 -$4500 with a 120l tank how does this compare with what you guys have had installed.

[DJ’s Timber]

Jim, I had mine done about 4 or 5 weeks ago and it cost me $4250 with the gas injectors and a 60 useable litres tank.

[outback]

2500 sheckles, mine is the boring old vanilla flavoured variety. After John gave me a hand, It has nearly paid for itself. We lost a shellacing lot of room from the boot, vertainly makes ya rethink what you need to take with ya.

[Jim Carroll]

Thanks DJ, with the 120l tank we should get about 100L useable.
It will be going into the tray of an AU ute so no real loss of space.

[station-rat]

The two main reasons to run petrol through in a dual fuel car is to keep the injectors clean, and to lube the upper cylinder, if you don't run a automatic lube system.
Station-rat:cool: