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New member with VU LPG removal issues

aceofhearts

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Hi everyone,

I have just signed up from not so sunny England as I was hoping to get some help with a problem on my 2002 VU Ute (LS1)

I really wish I hadn't started working on it today, but as I had the day off work I wanted to clean up the engine bay and remove the remainder of the crappy LPG wiring. The LPG was disconnected before I ever got the car, but the changeover switch was still in the dash and lit up.

So today I removed the rest of the system which all seemed to go well. It was only the changeover switch, a few earths and a single injector cable that I had to disconnect from the car, but now it won't start!

The fuel pump relay clicks, fuses are all ok but the fuel pump wont prime. It will crank but not start.

I have a feeling the changeover switch was left in as it was somehow allowing the petrol fuel system to continue working. I don't know how these are normally wired up and how it can be stopping the fuel pump, but I guess its job originally would be to stop the pump when the car is running on LPG. Annoying though as I cannot see anywhere else that looks like the original loom has been broken into.

Sorry for the long post, and I hope I have explained it ok. I would be massively grateful if anyone has any LPG experience on these cars.
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strgas

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Check injector pulse more than likely the inkectors have no power or pulse .
The wiring from the lpg system may have a simple relay to cut power to the injectors or a control module mounted under the dash or engine bay .
 

mechanic

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What did you do with the changeover switch wires? Did you bridge the 'petrol' switch wires together?
The changeover switch diverts power to either fuel pump, or LPG system. If you don't reconnect the wires, neither side will operate.
 

aceofhearts

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What did you do with the changeover switch wires? Did you bridge the 'petrol' switch wires together?
The changeover switch diverts power to either fuel pump, or LPG system. If you don't reconnect the wires, neither side will operate.
I didn't see anywhere where they were connected back into the original loom, most went into the engine bay and were already disconnected, and there was a ground and a live taken from under the steering column. I didn't see any where they connected back into the main cars loom.

I know what you are saying though, and in my frustration must have missed something. There must be a break in the fuel pump wiring somewhere that was diverted through that changeover switch that I need to find.

I will go back tonight after work with a fresh pair of eyes :)
 

Trevor loves holden.

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The switch would act the same as a toggle switch it breaks the power or earth to the relay you going to have to find the ends you removed to bridge them again, not sure but if it was fuel assist that means the LPG module would of controlled the fuel pump shut off or injector pulse, so one wire would of ran to the module another back to were it was cut to make the compete circuit. so when removing those wires 2 of them must of being joined.

You can test the spark by removing one coil 2 leads and try starting if the spark jumps post to post then you know its fuel related and not spark.
U can test with a test light to see if the injectors are pulsating while starting.
 
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aceofhearts

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Fixed! Thankyou for the suggestions.

A day away to think about it, and coming back with fresh eyes definitely helped. Found this buried in the wiring



The purple wire is the fuel pump feed, and the wires bridged onto it are what I thought were used for the aftermarket fog light, hence why I dismissed them yesterday. Bridged over now though and the car runs! I will have to get my soldering iron from the garage tomorrow and remove it and repair properly.
 
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