Duel Fuel 5ltr running bad on fuel

[Calais8]

Hey guys i recently purchased a 5.0l and its running weird on fuel. On gas it runs fine. Once its on petrol if you put the foot down the car wont rev passed 3000rpm. It sounds like ive hit a limiter and it really struggles.
Ive just done a service including oil flush, filter, coolant, thermostat.

Car is pretty much stock minus a cat back exhaust.

[Calais8]

Anyone experience anything like this?

[antondude]

Im on duel fuel myself and i notice to start the car set on gas it turns over instantly and when it starts set on petrol it can take a while for turnover, but never had the acceleration problems.
However when on fuel my car when accelerating makes a high pitch squeal and on gas quiet... hopefully nothing much.

[DAKSTER]

Just a guess but tuning a dual fuel car is a compromise. An ideal tune for petrol only is completely different than an ideal tune for the same engine running on gas.

If the previous owner was like me and almost never uses petrol, he may have the tune biased towards gas, as I do. This means it runs better and more economically than it otherwise would on gas, but also means that like mine it runs like crap on petrol.

You may be able to help that a little by running premium fuel, with its higher octane being closer to 110 octane LPG, though of course there is a lot more differences in the fuel than just octane rating.

If thats not the cause, then you need to look at systems specific to the petrol, such as the fuel pump system, fuel filters etc.

[emmtee83]

I am having a similar problem, except when running on fuel, the car stops running completely. she'll start up, gets to about 1500rpm then shuts off. one thing i did notice however is that i get an engine warning light when i run on fuel, but it disappears when i run on gas....i have checked leads, dizzy cap, changed the coil recently, any ideas guys?