Jump to content

Help Required Regarding Lpg System


Recommended Posts

  • Platinum Member

Good afternoon,


I have this picked up a Commander this week to replace my WJ as my daily (As i have plans for my GC). Anyway this this commander has the 5.7 Hemi and it is fantastic! I got this from a family friend who has had this for over 10 years so i know its been looked after and maintained. I only acquired this has his work commitments have changed and he is working from one and his jeep has been off the rad for 9 months. 


Picked it up and did an MOT and the emissions were fantastic even though its got over 200k on the clocks! Anyway i am having a problem with the lpg system. i used the lpg out of the tank which was working perfect with petrol and gas and swapping over. Yet once it ran out i took it to Morrison's and filled it up and it took just under 80 litres.


Yet the following day i did 10-15 miles and whilst i was driving on gas it flicked to petrol so i flicked it back and the car cut out dead. a few miles later i tried it again with my foot down a little and it hesitates and switches back to petrol. yet the controller constantly bleeps until you press the button to stop it bleeping. It has a Prins Lpg system and its never gone wrong for Andy yet it has for me. Probably because its been off the road for so long am guessing. 


This is my first Lpg car so not sure what i am looking for/at. Yet i've read the Prins workshop manual and its saying it has gone into a serious failure mode which is why its not switching over to lpg. I did notice though reading the document that they have a temp sensor for the water that goes to the regulator so am guessing if that sensor has gone faulty that could be the cause as they rest of the components look fairly substantial and basically just a diaphragm which rarely go wrong but could do with some help on this before i start spending money. 


Any help is appreciated. Matt

Link to comment
Share on other sites

  • Platinum Member
2 hours ago, TimC said:

Can’t help with your LPG problem but..........a 5.7 Hemi Commander! Ooooooooh, very very nice 🤗

I hope somebody can come across soon for some help but yes the Hemi is truly fantastic and goes very well indeed! 

Link to comment
Share on other sites

  • Platinum Member

I have an old prins system on my XJ, and i also experienced similar problems when I first acquired it. 


Things I checked;


Gas filter on the supply feed into the evaporator, these can get bunged up with residues, depending on type you can clean or replace. - mine was clean🤔


Is the water temp on the engine getting up to working temp on petrol, a faulty thermostat may keep it too cool, and therefore not get warm enough to let the evaporator work correctly. - thermostat was ok🤔


Does the water supply run tandem to the heater matrix or in series, mine was running tandem, and never received enough flow through the evaporator due to heater taking the bulk of the flow, I proved this by clamping the heater pipe (upstream)with a g clamp forcing water through evaporator.  and sure enough, the evaporator warmed up and the LPG kicked in. It turns out that this was all due to my jeep not having the heater control splitter valve to direct flow away from the heater when not in use. It's now plumbed in series and gas kicks in within a 30 seconds to a minute of the engine starting. 😉🤗


Hope this makes sense and is of some use to you.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information