HELP VX V6 Dual Fuel Hard starting when Cold only

[bfhoon]

Hi

With the colder weather coming up this is getting more annoying. The car is dual fuel and starts just as pathetic on lpg or petrol doesnt matter. So first start in the morning after car has not been used for a good 12 hours. It kicks fine starter is only 1 year old but then stall straight away, try again stalls with some coughing and backfiring through airbox, try again cough and backfire through airbox then just maybe on the 4th go it will either do the same or start as per normal, then for the rest of the day its fine start first time every time no fuss at all. What should I be looking at as I hate it spluttering and **** sounds like a pistons gonna break through the block stuffing around with it on the mornings cold. What could this be? The car starts on petrol for 1 second then switches to gas, I have also overridden this to start on lpg and also to start on petrol and stay on petrol it all does the same thing. Fuel filter is probably coming on one year old and injectors who knows I havent removed them and car has 250,000klms on it but I would think if its clogged filter or injectors it would happen all the time not just when the engine is cold. Anyone got any ideas.

Thanks

 

[hotrod]

could be lots of things , injectors blocked , air flow meter , ICV , TPS , oxy sensors x2 , dfi , coils , spark plug & leads , vacuum leak , fuel pressure valve , split inlet pipe , mate it can go on and on , see if it throws any codes with a scanner tool.

 

[bfhoon]

Hi

I ran a wire between pin 5 and 6 to get my engine light to flash but I have no idea on how to read it. I have tried but I have video taped it I will put a link up on youtube in the next 30 minutes and leave the link here can someone tell me how many faults I have and what the fault is the vide kept going after 5 minutes so im not sure if I had hundreds of errors or if it just keeps cycling through the same thing. Anyones help will be much appreciated.

Thanks

 

[Sabbath']

It will be cycling through the same codes.

But you wont find a fault more than likely because the gas is an aftermarket system. I'd be looking at a converter that is gumming up, and it's not until the heat gets sufficient does it unstick for normal operation.

Try pouring boiling water over the converter first thing in the morning before you try to start it. If it then starts normally, you've located your problem.

 

[bfhoon]

HI Everyone

Please see below video if anyone can tell me whats going on would be great

 

[bfhoon]

Hi

Can anyone help me out with the cold starting issue what is the most likely piece of equipment to check or fault find. I have heard something about oil sender unit can cause starting trouble. How would I test this with a multimeter to check.

Thanks

 

[EYY]

Get somebody to add 12v one of the gas solenoids at exactly the same time as you start cranking it. If that works then you know it's your oil pressure switch.

First, try turning the key from accessories to on 3 times and then try and start it. This will prime the fuel pump. If this works you will be losing fuel pressure over night. Turn it to gas and do the same thing. If it starts alright then that will indicate that either you're losing fuel pressure, or your petrol overlap isn't long enough, or you need the gas to be serviced.

 

[bfhoon]

Get somebody to add 12v one of the gas solenoids at exactly the same time as you start cranking it. If that works then you know it's your oil pressure switch.

First, try turning the key from accessories to on 3 times and then try and start it. This will prime the fuel pump. If this works you will be losing fuel pressure over night. Turn it to gas and do the same thing. If it starts alright then that will indicate that either you're losing fuel pressure, or your petrol overlap isn't long enough, or you need the gas to be serviced.

Realisticly though shouldnt I be able to either start it on petrol or gas and since I have trouble on both one would assume its not a fuel related problem as I get the same result whether I try starting on petrol or gas? It does start but stalls straight away lots of spluttering backfiring and popping, like I said once warm car is perfectly fine starts first go everytime seems weird to me surely someone has come across this before I coldnt be the only one

 

[EYY]

The car will always start on petrol. That's why you add 12v to the lpg solenoid when cranking.

 

[TumTum]

The car will always start on petrol. That's why you add 12v to the lpg solenoid when cranking.

+1
You might have an older system (eg Elko) where the time petrol is delivered during start can be adjusted. If so, it may just be too short and the engine starves before the gas pressure is normalised. My vx has this setup and the timer was set too short initially and with blocked petrol fuel injectors, my startup was like yours. A few tanks of premium with injector cleaner and an adjusted timer and she's a lot happier now.