LPG / Petrol - how can you know that you are running on Gas? (1 Viewer)

Apr 6, 2019
3,693
7,299
Eye, Peterborough, UK
Funster No
59,702
MH
RV
Exp
FourWinds Windsport 6.8L V10
Hopefully not too silly a question, but my LPG guy is on holiday for a week and after being so helpful replacing a crusty 20 year old tank I am not going to disturb him (despite becoming friends and gave me his mobile).

I have a simple switch on dashboard - right for Petrol and a red LED - left for LPG and a little amber LED - the system is 20 years old.
When I first got the RV there was a blip in throttle downwards when you flicked from LPG to Petrol - understandable and fine by me as the solenoid flicks open the right valve and lets petrol in etc... especially as the RV had not been driven for about 9 months so I blew the cobwebs away with a trip from Anglesey back home to Eye.

NOW, there is no blip. So, how can I simply tell if the relevant valve etc has opened and the engine is actually using the LPG? I am yet to cinfirm if the petrol gauge has been dual wired to display LPG levels as previous owner said not to rely on the gauge - use 320 miles as a good indicator it is time to fill up with LPG again.

Images below of the engine and what i took to be the LPG atomiser in more detail. If I pull the top connector OFF and start the engine it just starts and runs regardless of Petrol / LPG switch. I wrongly? assumed this might turn off the atomiser and stop LPG being selected.
 

Attachments

  • qqq4.jpg
    qqq4.jpg
    374.8 KB · Views: 45
  • qqq3.jpg
    qqq3.jpg
    919.2 KB · Views: 39
  • qqq2.jpg
    qqq2.jpg
    958.8 KB · Views: 40
  • qqq1.jpg
    qqq1.jpg
    777.7 KB · Views: 46
Aug 6, 2013
11,941
16,533
Kendal, Cumbria
Funster No
27,352
MH
Le-Voyageur RX958 Pl
Exp
since 1999
Pinch flat the large rubber elbow when on LPG. The engine should stop. The elbow is the LPG feed.

Subscribers  do not see these advertisements

 
Dec 2, 2019
3,949
8,887
South Lincolnshire
Funster No
67,140
MH
Rapido 7065+
Exp
Broken most bits now
Hard to tell from just piccys where the vapouriser is but it looks like it's the circular thing on the bottom right so I'd check the solenoid attached to it - 12v supply when on gas.

lpg.png

Subscribers  do not see these advertisements

 
OP
OP
Jev88
Apr 6, 2019
3,693
7,299
Eye, Peterborough, UK
Funster No
59,702
MH
RV
Exp
FourWinds Windsport 6.8L V10
Hard to tell from just piccys where the vapouriser is but it looks like it's the circular thing on the bottom right so I'd check the solenoid attached to it - 12v supply when on gas.

View attachment 517487
Perhaps you didn't see the three other pictures that were close ups of the vapouriser ?
I have now sorted the problem - LPG tank valves have their own 12v feed and this fuse had blown. I get a distinctive dip in revs when switching fuels. This disappeared and so made me suspicious that something was amiss.
 
Dec 17, 2016
951
955
Malvern
Funster No
46,488
MH
Hymer B525 2006 A cl
Exp
2012
On the system I had in a car ( several years ago) the amber LED changed to green when on LPG.

Agree about range anxiety -I used to reset the trip counter on fill up as the LEDs were useless. You could get a Mopeka sensor which will work with a cylindrical tank but the big difference is that with the engine aftermarket system you will always have a big petrol tank as a back up so not so necessary.
Glad you sorted it anyway.
 
OP
OP
Jev88
Apr 6, 2019
3,693
7,299
Eye, Peterborough, UK
Funster No
59,702
MH
RV
Exp
FourWinds Windsport 6.8L V10
On the system I had in a car ( several years ago) the amber LED changed to green when on LPG.

Agree about range anxiety -I used to reset the trip counter on fill up as the LEDs were useless. You could get a Mopeka sensor which will work with a cylindrical tank but the big difference is that with the engine aftermarket system you will always have a big petrol tank as a back up so not so necessary.
Glad you sorted it anyway.
Unfortunately no colour change on these LEDs. Mopeka not much use as yet because;
1) I have three LPG tanks for the engine and two are exposed to road rash so would have to fashion an enclosure for Mopeka?
2) The 3rd tank is under the bed and now know it actually has a gauge! But will also investigate the 3rd tank and see if Mopeka could slide underneath - not sure how much use this would be as the three tanks all feed through a manifold, so would the reading on one slightly raised tank give an approximation to all three tanks contents? I am having to assume the tanks all empty under pressure at the same rate and equalise between them?

Subscribers  do not see these advertisements

 
Dec 17, 2016
951
955
Malvern
Funster No
46,488
MH
Hymer B525 2006 A cl
Exp
2012
I see your problem! If they do all equalise the one Mopeka sensor might work. This would need protection from road dirt in something that you could access to change the battery on the sensor.
 

Mondo74

Free Member
Jun 24, 2021
35
24
Aberdeenshire, UK
Funster No
82,151
MH
Adria Twin On Order
Not at all helpful in your case but when I drove Police Cars circa 2004 with LPG tank fitted there was a very easy way to tell if you were on LPG or Petrol. On a blues and twos run, if you overtook cars going up hill you were running petrol, if they overtook you, you were running with LPG. Simples.
 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Latest journal entries

Funsters who are viewing this thread

Back
Top