Tartarini VW Aircooled camper - won't run on gas - help!

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kembiff · #1 Post by **kembiff** » Sun Jul 08, 2012 3:13 pm

My 1971 camper wouldn't run on gas today so I had to use petrol (which worked fine).
I thought it was electrical. A relay perhaps but having checked it out just now I'm no longer sure.

Here are the symptoms:
When the LPG is activated from the dashboard switch I get the click at the tank and the 2nd click at the regulator. A small amount of gas flows out then the regulator stops the flow completely like it is supposed to if there is a leak or something. There isnt a leak it just keeps shutting itself off after maybe 3 seconds or so. Any ideas anyone?

The system is the type where a pipe for the LPG just sits on top of the existing carb.

rossko · #2 Post by **rossko** » Sun Jul 08, 2012 6:04 pm

Look to see if switch or controller is getting a reliable RPM signal - a gas system should shutoff after a few seconds if the engine stops. See if you can work out if the shutting off is cause or effect - i.e. does it shutoff and cause a stall, or does the engine stall (say due to poor/excess gas flow) and then shutoff.

kembiff · #3 Post by **kembiff** » Sun Jul 08, 2012 6:47 pm

Thanks for your advice. There is no rpm sensor it really is a very simple system! The gas just stops coming out once I have run the Carb bowl dry and switch over the rocker switch to lpg then I get the 2relay clicks then a soft click as the regulator shuts down the gas supply. Any more thoughts?

Gilbertd · #4 Post by **Gilbertd** » Sun Jul 08, 2012 6:51 pm

Unless it is a homemade LPG system, it will have an RPM feed. Usually a brown wire attached to the negative side of the ignition coil.

rossko · #5 Post by **rossko** » Sun Jul 08, 2012 7:50 pm

If it has no RPM sensing of some kind, it won't pass any kind of safety assessment. It is possible to cobble similar arrangements using e.g. oil pressure switch.

If you have nothing like that, then there won't be any other means for it turn off the gas solenoids by itself. So you'd need to check if that is what is happening, as already described and ignored; or assume it is a wiring fault e.g. wonky earth, power supply, switch etc. that causes the solenoids to lose power after a short time.
My money is on a failure of the failsafe feature that you don't know you have got.

kembiff · #6 Post by **kembiff** » Sun Jul 08, 2012 8:06 pm

Thanks for your help. How could I tell where the failsafe mechanism is?

I've had the engine out several times for other reasons and can't see any sort of feedback to the LPG system. There are certainly no wires going from the engine to the regulator at the engine end of things apart from one yellow wire which attaches to the negative side of the coil. Pulling this off makes no difference to my problem. I'd always assumed it was some kind of earth.
Would it help if I posted a picture of the engine bay and regulator on here?

rossko · #7 Post by **rossko** » Sun Jul 08, 2012 8:31 pm

kembiff wrote:There are certainly no wires going from the engine to the regulator at the engine end of things apart from one yellow wire which attaches to the negative side of the coil. Pulling this off makes no difference to my problem.

That's the one, that would carry pulses from the -ve of the coil. See where it runs to - perhaps the dashboard switch (they usually contain built-in RPM sensing) or to a seperate "safety relay" (which is an RPM sensor in a box). It's entirely possible the RPM sense circuit in whichever you have has expired, if you are sure the yellow wire is secure and unbroken.

kembiff · #8 Post by **kembiff** » Sun Jul 08, 2012 8:43 pm

Oh great - thanks for that. I'll investigate where it goes tomorow and get back to you.

kembiff · #9 Post by **kembiff** » Mon Jul 09, 2012 12:01 pm

Thanks again for your help. I checked the continuity of the yellow wire today and it is fine - no breaks. It goes straight from the coil to a relay shaped box (about 40cm) with 5 wires going to it called - yes you guessed it! - 'Lextron LSS230 safety switch'. I know what that is now!! I took it off and checked that all the connections were sound especially the yellow one and shook it. Nothing rattly inside. Put it all back where it should be and hey presto the bus runs on gas again!!

So, I hate intermittent problems like this. Could have been a loose connection or a sticking relay but I'm going to seek out a new safety switch now in case that is on its way out. Any good ideas for the best place to get one please?

The conversion is at least 10 years old now so is there anything else I should look into replacing/refurbishing whilst I'm seeking out bits?

Once again, many thanks for your advice and support.
I have 2 LPG vehicles at the moment and have managed to get them both working again now.

rossko · #10 Post by **rossko** » Mon Jul 09, 2012 1:37 pm

http://www.tinleytech.co.uk/acatalog/El ... nents.html

kembiff · #11 Post by **kembiff** » Mon Jul 09, 2012 1:45 pm

Thanks - thats a few quid cheaper than the autogas2000 price. I did wonder if any other sort of relay would do the job but best not mess about with flammable gases and safety systems eh!!

Gilbertd · #12 Post by **Gilbertd** » Mon Jul 09, 2012 6:45 pm

It's not just a relay. It's a relay that will only stay energised if it sees a continuous stream of pulses on the one input, if they stop, the relay drops out to shut the system off. Best to use the real thing although BMW and Merc used something similar in the 80's and early 90's to power the petrol pump which could be used if you were really stuck.

1975bay · #13 Post by **1975bay** » Tue Jul 10, 2012 6:32 pm

Hi mate I have a 1975 baywindow and would like LPG.
Where did you get yours converted and how do you heat the gas?

kembiff · #14 Post by **kembiff** » Tue Jul 10, 2012 10:48 pm

You should probably start a new thread but anyway...

I had it fitted by a garage in Durham called Hendersons (actually they were rubbish [I've replaced just about every electrical and gas connection on it!] and don't do it anymore anyway!). There is a specialist in Meadowfield http://www.agpl.co.uk/ and also one in Tanfield - who also happens to own a bay himself http://www.djautogas.co.uk/ . It cost me £1100 ten years ago.

Its the best thing I've ever done to the bus because I can now afford to drive it (I take it to the south of France every summer!)
LPG does seem to make the engine run hotter and can knack the valves so this year (after another lowloader experience) I have fitted something called flashlube which is supposed to stop this problem. Also the tank fills all of the back seat space but then it has to go somewhere. BTW the heat comes from a long coaxial style tube that gets shoved down the silencer. Start on petrol then turn off the fuel supply after about 1/2 a mile and when the float chamber is empty and the engine cuts out quickly flick to gas on the move.

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