VT wont rev on petrol

[VT_Holden83]

MY 97 VT won't rev on fuel, but runs fine on gas.
I have replaced & checked fuel pump, fuel fliter, injectors, flushed the tank & lines, done TPS, fuel pressure regulator & rail, air speed sensor, catalytic converter & no trouble codes come up on tech ( 02 sensor reads normal.)
Car is not duel fueling, i have removed the mixer & it did not fix the problem.

I'm really hoping someone here will be able to help as i've done everything i can think of & nothing has worked.

Thanks Phil

[BT1-355]

If you have check all of the ABOVE ^^^^^, then the only thing left is the air flow meter. Very common if the car is duel fuel, due to backfiring. They can only take a few back fires and there are gone.

[VT_Holden83]

Checked that as well, Thanks for your help

[Tsunamix]

Checked throttle cable ? Might be a bit obvious but I'm unsure if the mixers had there own Throttle butterfly. Old older cars that had a dual path inlet for dual fuel, there was. Haven't seen a dual V6 commy though so I'm out on a limb.

What else ? Umm.. Is there someinthing that gives a seperate timing advance curve for LPG as opposed to petrol or does it run from the one tune source ?

Lets see, the equation is fuel plus O2 plus spark = bang. Fuel you have looked at fairly thoroughly....wait...wait..something coming into back of head here.... Faulty valve in fuel line allowing fuel to vent back to tank rather than pressurise the injector lines ?

Spark side looked at ECU

O2 - must be fine if it still runs fine on gas...

I'm out of ideas

[VT_Holden83]

Have replaced the fuel pressure regulator are there any other valves in the fuel tank?

[Tsunamix]

I have a feeling that there is one in the pump itself. Best way to check is probably to slap a pressure gauge on the fuel rail and see what the pressure at the injectors is.

If theres ample fuel pressure, then maybe the programming on the injectors is misbehaving ? Which would kind of make sense as the gas system uses a different introduction method.

Pity you can test these like in the odl days when each injector had it's own lines. Then you could drop out an injector, plug the Injector hole and run the engine into a test bucket. You could see what the injector was doing.