Using to much petrol on vapor injection

[mmjlw]

I have recently installed vapor injection on my SS-V and while it has been running well I have been using a 1/4 tank of petrol to 3- 4 tanks of gas. :flipoff: I mainly run my car up and down the freeway and always run it on gas but I seem to be using a lot of petrol I have taken it back to the installer which happens to be my holden dealership (I live in the country and it was to far to take to Melb to get installed) and they said that the mixtures were out and they fixed the problem, however it has started again and they have no idea what is wrong. i'm using about 4 litres of petrol to 120km of travel and that on gas.
Any help would be greatly appreciated

Mark

[Tre-Cool]

you shouldnt be using any fuel on gas period.

sounds to me they havent shut the fuel pump off?

or typically your using fuel to get the engine upto temp before switching over.

[Big_Valven]

I have been using a 1/4 tank of petrol to 3- 4 tanks of gas.

That seems normal as vapour injection only uses petrol until the engine reaches operating temperature.

[DaveHAT]

I have recently installed vapor injection on my SS-V and while it has been running well I have been using a 1/4 tank of petrol to 3- 4 tanks of gas. :flipoff: I mainly run my car up and down the freeway and always run it on gas but I seem to be using a lot of petrol I have taken it back to the installer which happens to be my holden dealership (I live in the country and it was to far to take to Melb to get installed) and they said that the mixtures were out and they fixed the problem, however it has started again and they have no idea what is wrong. i'm using about 4 litres of petrol to 120km of travel and that on gas.
Any help would be greatly appreciated

Mark

Depends on how the LPG computer has been configured. What LPG system is it?

In winter it'll use more petrol as it takes longer for the engine to reach op temp & also ... If the LPG PCM is configured to return to petrol at idle as well as at start up, you'll use more. This is sometimes done to give a smoother idle than LPG can.

Something definitely doesn't sound right or isn't configured the way you like it, so you're only real option is to suck up the travelling and take it to an LPG specialist to get it inspected.

Ask the dealer where they got the system from and see if you can take it direct to the manufacturer/supplier to get it looked at.

[redvxr8clubby]

I don't have an answer for you Mark, but I have a question. You live in country Vic and converted your SSV to gas. Until recently I had an Falcon E-Gas wagon at work, and when you see fuel prices in the city at say $1.20 and gas a less than 50 cents it's easy to see the economy of gas even though it uses about 20 - 30% more gas than a petrol car. When I go to the country and see petrol at similar money (usually a bit more), but gas at nearer to 70 cents considering the extra gas usage I wonder is it worth it when you are filling up with gas at that price. Consider also you pay more for the car or conversion, and loose bootspace. So if you assume your combined fuel/ gas usage is normal and doesn't change, do you still consider it's worth converting, and what km's do you average. On a country run I could get about 800 Km's out of the wagon which would take 100 litres to fill, so about 12.5 l/ 100 km - dedicated gas. The gas Falcon puts out quite a bit less power than petrol 6.

[PoweredByCNG]

Injected LPG systems will ALWAYS start the engine on petrol regardless of coolant temperature. If the coolant temperature is > 40C, the system will switch to gas almost immediately once the engine has fired over however in winter, it may take several minutes for the coolant to reach this preset temperature. The system will also use petrol if the gas injectors cannot supply enough gas to the engine to ensure a stoichiometric mixture (i.e. under high load conditions).

What system do you have?

Regards,
Dave

[mmjlw]

Thanks for the replys guys I have a Parnell system. (I will check the model etc when I get a chance) My car starts on gas and it changes over after about 2 - 3 km of driving or about 5 minutes letting it idle in my garage. I'm waiting for the installer to come back to me with an answer then I will take it to a specialist in Melb and see if they can sort it out and pay for it.

redvxr8clubby. I decided to change my car over to gas due to the fact that i'm travelling approx 60000 - 65000km a year and I can save about .70cents per litre on average so for me its going to save me money and I will pay for it in about 18months or so. I use to get approx 600 - 750km per tank on petrol depending on how much city or around town driving and on gas I am getting approx 550 - 650 km on a 69 litre tank. I don't drive my car hard and usually sit very close to the speed limit which is very hard at times.

[morpheousssv]

Mate I am getting average 400k and at best 430k to a tank of LPG in my VESSV so you must have a late switch over issue onto Gas after start up. I switch over hot or cold in 60 seconds. Those k's your getting are unbelievable as I have been using LPG since April 07 and never seen those figures even country driving. Sprint Gas is the brand I have installed. Do you know your emission readings??

[vyssbeast]

The few kms when cold etc will add up ...

I filled up a full tank of petrol in my alloytec exec at the start of may and it just finished ... but that was at least 5000k ... so it'll happen

Best thing to do is fill a full tank of petrol, note the kms then forget bout it till that tank of petrol is almost empty then see how many kms that took ... factor that into your calculations and you'll still be saving money on gas...

edit: that should work out to perhaps 1-2L/100km (petrol) used along side the gas

[mmjlw]

I have completed 6188km and used 815 lrts of LPG and 187 Ltrs of petrol. I am more concerned that I'm the system is feeding petrol and lpg into the heads and that will cause a problem.
I would be happy if I used only 1 tank of petrol per 5000k but 3 tanks is a bit much.

[whitels1ss]

My brother had a car a couple of years ago that had a gas conversion on it and the guys who did the conversion had farked up so that when you switched the car on gas it was supposed to switch off and isolate the petrol injectors and they had it wired wrong to isolate the fuel pump instead.
As a result when you drove the car, especially at highway speeds the petrol injectors were pulsing and the intake vacuum was sucking petrol through from the tank!
It took a couple of mechanics to work out what was wrong.
If it is an aftermarket conversion on yours could be the same thing as your car should not be using anything like that much petrol.

[PoweredByCNG]

If it is an aftermarket conversion on yours could be the same thing as your car should not be using anything like that much petrol.

The systems being described in this thread are quite different to the bog-standard LPG conversions normally fitted to pre-2004 cars. The new breed of injected gas systems will always use some petrol during startup, even when the engine is warm. In some cases, petrol will be injected alongside gas when the engine is under high load to ensure correct air/fuel ratios if the gas injectors can't flow enough to meet demand.

Regards,
Dave