Vk 308 fuel issues

[exec24]

I have a VK 308 which is Dual fuel

I want to Remove the Gas System(Out of Date) plus it looks Crap

Car runs on LPG ok, but not 100% perfect, as soon as you flick it to Petrol It Stalls(wont start on petrol at all)

We've poured petrol down the Carby, which it then runs on perfectly (idling)until it runs out,

VK's as i understand have an intake pump only from Factory, Mechanical one is Blocked off

I Have Removed the Fuel Filter and it was Dry, so i removed the Pump(tested it, which it didnt work at all)and replaced it and also replaced the Fuel Filter at the same time, along with new hoses for both of them

Turned the gas off and ran it out, so theres none in the carby, then switched it over to petrol, car started to run, was a bit rough and it wouldn't idle under 1500rpm, and kept stalling

then after a few times of it running and stalling, it wouldn't even start, the starter only engaged with a single click

have checked the fuel pump relay and there is constant power to it and accessories wire, and the fuel pump isnt getting power from the relay

do the 308 fuel pumps pressurise up then cut out (like later model commodores) or do they constantly run? as this one seems to

[Darren_L]

VK & even VL all used a mechanical pump. The intank electric pump was a pickup pump only.
So either you car is just running on the pickup/primer pump or they've replaced the intank pump with something aftermarket.

the pickup pump will prime for a few seconfs when you first switch the ignition on, and then turn off until the engine starts.
I'd be either fitting a mechanical pump back on, or pulling out the intank pump and confirming what sort of pump it is. If it's only the factory primer pump, then it's not going to be up to the task of feeding full fuel supply to the engine

[exec24]

Not all VK's use Mechanical Pumps

On my Genuine VK workshop Manual it says that the Mechanical Pump, has been Deleted and replaced with a Intank Pump

the VK Has got the mechanical Pump Blocked off on the timing cover(exactly how it mentions it in the workshop Manual)

the fuel pump however runs constantly doesnt prime and turn off

[ari666]

VK & even VL all used a mechanical pump. The intank electric pump was a pickup pump only.
So either you car is just running on the pickup/primer pump or they've replaced the intank pump with something aftermarket.

mate, no matter how many times we chat about this, one day you are gonna listen to me

some VKs didnt have the mechanical pump. they just used the pump in the tank. and yeah, its pretty much no good for anything but picking up fuel, they still used them and them alone.

OP, they are hooked up to a tachometric relay. so the car needs to be running, and pulses sent to the relay for it to work. it primes for a bit then shits off. your cheapest option is to go fit a mechanical pump which is about 90 bucks and 30 mins of work, but personally i would fit a elec pump.

so: if you tip fuel into the vent whistle, the car will start and run for about 30-40 seconds?

[exec24]

OP, they are hooked up to a tachometric relay. so the car needs to be running, and pulses sent to the relay for it to work. it primes for a bit then shits off. your cheapest option is to go fit a mechanical pump which is about 90 bucks and 30 mins of work, but personally i would fit a elec pump.

so: if you tip fuel into the vent whistle, the car will start and run for about 30-40 seconds?

when you mean vent whistle, are you talking about the the tube up front? have been pouring fuel into that and it does star an run on that for 30 seconds before it stalls, when it runs out of fuel

the tachometric seems to be ok, have tried more that one, BUT....

it has Power, earth and Ignition, it also has the Coil (12v-) wire which get power when the car cranks, and starter signal seemed ok, but the power to the fuel pump is working sometimes and Not working when i check it othertimes(physically checking it with a test light) from the terminal coming out the relay

even sometimes when you switch it on to accessories, the pump(when it is working) runs constantly
i have also checked the fuel going to the front of the car has fuel up to the side going into the factory fuel filter thing that is in front of the carby

also noticed the reverse lights stay on, while in park

im a bit confused, i dont know what to do