LPG Gauge and tank capacity...?

[raf_sam]

Hi everyone,

To start, I was a LPG virgin until this weekend when I bought a pre-converted Range Rover Vogue and I’ve been quietly impressed so far!

I just have a few questions that I either didn’t think to ask the seller or appreciate at the time. I hope someone can help. For info I’m running a STAG 300 Plus system with Irene 94L tank and OMVL reducing valves with regular injection strip.

1. What is the max I can fill the tank? I’ve heard some people suggest 80% - so this would be 80% of the 94L I'm guessing? However, when refilling the other day the pump cut out after about 20L...?

2. The gauge isn’t that accurate, flipping from one (of four) green lights to one red AFTER topping up with LPG and occasionally going from one green to two green lights while I’m driving. From what I’ve read, I know that gauges arent’t that accurate, but does this sound right? Are there any more accurate gauges and how easy are they to change over?

Thanks guys,

RAF_SAM

[Dualtech]

Hi, you are correct in saying that the tank should hold 80% of the water fill capacity(94ltr). About 75ltrs useable from empty.
The gauges are never brilliant, although yours does sound pretty bad, not sure if you can perform any sort of calibration or fine tuning of the level reading on a stag system, as you can on others.
Might be best to just use your trip to get a idea of how many miles you get to a tank.

[Taught2BeCautious]

The fill valve on your tank works a bit like the float-valve in a toilet cistern, and is designed to cut off when it reaches a certain level, which is why you might get unexpected results if the tank isn't fitted at the correct angle, or you fill-up whilst parked on a slope.

If certain filling stations give you less gas than you get at other locatios, it could be that the pump is fitted with a sensor that cuts out at a certain back-presure.

Some years ago, I had a 46 litre tank that suddenly stopped taking more than anout 20 litres, which after trying everything else, turned out to be a faulty float arm on the fill valve, which had loosened slightly causing it to catch on the pick-up tube.

Some level senders are more accurate than others, like the opto-electronic ones for example, but you need to know what your current ECU supports - so check in the programming software to see what options you can choose before buying another type of sender!

A 0-90 ohm one will give a better resolution than an 0-50 ohm one, but you also need to match the travel on the sender unit's needle to the brass part that screws into the tank, as they can vary between 90 and 270 degrees of rotation between full and empty.

For example, the AEB 1090 is 0-90ohms, 90 degrees, the AEB 1050 is 0-50 ohms, 90 degrees, and the AC WPGH-1 is a 0-5 volt opto, 270 degrees.

You can also get variations where 'Empty' and 'Full' are the other way around, plus different fittings for 'Multivalve' or '4 Valve' types!

My ESGI ECU supports a number of different types, and allows you to alter the level at which the various LED's are lit, and also tells you what voltage it is reading at any time, so I set mine up like this:

First, I filled the tank and zeroed the trip meter on the speedo to see what sort of mileage I could expect before running out (ignoring the LED's), and divided it by 4 (or by whatever number of Green LED's you have on your gauge).

I filled the tank again, zeroed the trip meter, and ran the configuration software to set the 'Full' value of the gauge.

After running the car for the first quarter of the total mileage, ran the configuration software again and set the value for 3/4 tank, and again for 1/2, and so on - until I estimated I had about 30 miles to go to empty, and ran the software again to set the value for the Red LED to come on.

Its not foolproof, but a lot better than it was out of the box.

Alan.