Alfa 147 - LPGTECH Low Gas Pressure

[scottyf]

Hello All,
Problem number two.

I seem to randomly get LPG Gas pressure low. Then the car switches back to petrol. Might take five mins of driving on petrol before it can switch back.

I'm starting to think there maybe an issue with the valves on the lpg tank or solenoid.
As when its on I don't have any issues. The tank doesn't appear to have a leak or anything like that.
I can't smell or detect gas leaking.

Has anyone had any float sticking issue stopping gas going through?
Or the fail safe screw just sticking or locking?

Just seems a bit odd. Like sometimes I'd go over a speed bump and it'll shut off and I have to click it back on again.



Any help greatly appreciated.

[LPGC]

Cause could be a number of things..

Given you're not booting it over speed bumps: Fuel slosh in tank if level is low, excess flow valve (in tank valve) getting thrown closed over bumps, bad wiring connection to a solenoid or battery or earth, bad solenoid, bad wiring to pressure sensor (or failing sensor), solenoid relay in ECU (LPGTech has an internal one) failing and throwing open over bumps, otherwise bad ECU (track brakes etc - unlikely).

Tank to reducer Faro pipe trapped/kinking with suspension movement - but you won't have done that...

Given you slow down for speed bumps, if it happens when you come back on the throttle after the bump, could be as simple as setting cut back pressure in software to too low a figure / reducer pressure setting not high enough. If due to the latter, bare in mind that some reducers give a slightly different pressure between cold and hot.

Software readings while the fault happens may give insight, would check wiring to solenoids anyway.

Simon

[scottyf]

Thanks for the help. I will work through those things and see if I can spot anything glaringly obvious to start with.
Pipes all okay etc.
I'll check the software but I don't always have the leads on me to check but I am sure it will be something a bit simple.

I still hear the solenoids click in the boot where the tank is. But I'll need to check the one on the vapouriser.

I'll also check the reducer pressure but I know it was quite high anyway.

[scottyf]

Just to let you know it was a really simple issue.

I checked the solenoids, Any kinks, the gas lines, checked tightness of the fittings.
You know just checked over things. Ran the computer and software.

Then I noticed the thumb screw for the safety valve wasn't fully turned out. As I've been going over bumps it must have slowly moved round and closed a little.
So every time I went over a big bump it must have closed enough to lower the gas pressure.

So fully opened it again and it's back to working perfectly.

Thanks for your help Simon.


Good to go over everything anyway just to check as I've not checked it all in so long. Ready for its MOT next week.

[LPGC]

You may also have disturbed again the tank solenoid coil wires..

May have been the thumbscrew but would expect that to cause insufficient flow at high loads before intermittent closing over speed bumps.

Simon

[scottyf]

Either way its back to working well. So ill see what happens this week.