I have an interesting problem that has not been worked out. I have been to a few Mechanics and they are not sure were to start. The car has had an aftermarket gas conversion and runs well on gas. The problem is the fuel which it wont run on for longer than 3 to 5 seconds now and again. If switched to petrol sometimes you get the fuel working but you need to wait a few days before it thinks about kicking in again. Starts and runs fine on Gas

The fuel pump works (replaced) and all ECU diagnostics come back fine apart from all injector circuits most times. The last mechanic concluded that the injectors were pulsating and said that it could be low, dirty fuel. I half filled the tank left the garage and switched to petrol and it run fine for about 5 seconds then cut out.

I am not sure what to do next. I'm told its may cost a bit with trial and error exploration. Starting with new injectors which would make sense if it run or idled rough (when fuel works).

I am thinking it may be some kind of electrical issue as when it does go on petrol there is no missing. Could it possibly be some sort of relay that cuts off the injector to run on gas. researching the Internet some say it could be the Cam angle sensor but would that not have an impact on the ignition.

I asked the Gas Conversion specialist about a Injector cut out relay and he said sure bring it down (Miles away) but he wants the car all day. Before I do that as it sound like there will be added exploration and other related cost I thought I'd check with you guys

Anyone else heard of a simular problem or know of how the injectors are cut off when switched to gas out? If there is a relay were would I find it. The gas ECU is Gastech FP31.

Could it be the Cam Sensor?

Thanks

DJ

When was the fuel filter replaced last ?

The fuel filter was changed at the time of the pump about 6 months ago. The fuel has good return flow and pressure and I have pumped about 15l through it whilst idling on gas. (No cut out when running on Gas)

cam sensor should affect on gas as well -
use a test light and check for power at fuel injector when in fuel position with ignition on -look under bonnet for control relay connected into gas control wiring

Have you checked the actual fuel pressure at the injectors? If the fuel pressure regulator has failed, you would get excellent fuel return to the tank, but minimal pressure at the injectors.

Also, if injectors are unused for long periods of time, they tend to gum up badly and may not flow enough to run.