P38A LPG issue Resolved

As I posted a while back I needed to have the lpg system on my Vogue SE serviced as the previous owner had not tried or used it, maybe. I put some gas in it and tried it, it ran lumpy at low speed and under acceleration but at a steady 50 it seemed better.
So last week I took it to a local specialist in lpg for assessment and repair. His assessment showed it is running rich and worse on one bank of cylinders than the other. This highlighted worn injectors but it now turns out the system is obsolete plus the injectors are fitted under the inlet manifold so they are impossible to get to without taking the manifold off. He did say what the make was but I can't remember as stupidly forgot to write it down. He did give me an idea of price but with the winter only mileage I plan to do thought it was too much to recoup, which was fair, he also didn't charge me for the investigation work. So what to do next? Do I just leave it on the car and not use it, do I strip it down in the summer when I'm not using it and see exactly what's under the manifold and possibly find a fix or do I junk the whole system off the car if I can manage to some how use the existing gas up?
With regards to normal fuel it runs really nicely, I'm running it on Tesco Momentum and if I am careful on a run the average mpg indicated is about 26 and around town I get 16 but we all know this is very ambiguous figure but it's less than my old dse but not too much.
Let me have your thoughts or suggestions it might throw up something I have not considered.

The petrol injectors are under the plenum, or upper manifold. I wouldn't have thought there was room for lpg injectors too. What year is your car, is it bosch or gems?

Running on lpg makes sense on paper, in reality, not so much. There seem to be less and less garages selling it. You need to get the system serviced regularly and if it is an older obsolete system this will be expensive. The vehicle will do less mpg on gas, upto 20% less and it takes ages to fill up compared to petrol. On my old Kia sorrento, the O2 sensors didnt like lpg so I had a permanent engine management light showing.

Col

Colthebrummie said:

Running on lpg makes sense on paper, in reality, not so much. There seem to be less and less garages selling it. You need to get the system serviced regularly and if it is an older obsolete system this will be expensive. The vehicle will do less mpg on gas, upto 20% less and it takes ages to fill up compared to petrol. On my old Kia sorrento, the O2 sensors didnt like lpg so I had a permanent engine management light showing.
Col

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Does appear to be a dying fad. I've found the idea more trouble than it's worth having had such a system installed on a RRC years ago for the reasons given here, plus I'm convinced that it caused a liner slippage on my 3.9 back then.
Personally I wouldn't touch the stuff with the proverbial barge pole, but that's just my opinion.

kermit_rr said:

The petrol injectors are under the plenum, or upper manifold. I wouldn't have thought there was room for lpg injectors too. What year is your car, is it bosch or gems?

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It's an 02 4.6 one of the last ones with the Bosch Monotronic system. And yes it's somewhere under the upper manifold. Pic shows what I can see under the manifold, looks like an injector?

Andy Burrell said:

It's an 02 4.6 one of the last ones with the Bosch Monotronic system. And yes it's somewhere under the upper manifold. Pic shows what I can see under the manifold, looks like an injector? View attachment 260021

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The green thing is a bosch petrol injector

Ah OK. Looks like the system is made by Bigas in Italy but not sure if it is still made or have spares available. I have emailed them and a couple of places in the UK to try and find out.

If you follow the larger gas pipe from the vapouriser in the photo, it should take you to (hopefully) a filter and then to the injector rail

kermit_rr said:

If you follow the larger gas pipe from the vapouriser in the photo, it should take you to (hopefully) a filter and then to the injector rail

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There are two large pipes coming from the vapouriser one goes to the bottom of the throttle body and one disappears under the upper manifold.

Follow the pipes back two of them will be water pipes to heat the vaporiser

Yes, those 2 will be coolant and should get hot with the engine running.
There should be a metal pipe carrying liquid gas to, and a final rubber pipe carrying evaporated gas from the vapouriser to the injector rail

kermit_rr said:

Yes, those 2 will be coolant and should get hot with the engine running.
There should be a metal pipe carrying liquid gas to, and a final rubber pipe carrying evaporated gas from the vapouriser to the injector rail

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OK out of the back of the vapouriser there is a solid pipe with what looks like a valve of some sort and two pipes going to two filters. These two pipes disappear under the back of the upper manifold one each side to something solid I can just feel with my fingers. So still looks like a bit of a strip down to get to the injectors.
With the engine off is it OK to dismantle this to service it.

Should be OK if there's a solenoid valve on the tank. You may get a bit of gas escape, which will be pressure in the pipes.

stemac33 said:

Should be OK if there's a solenoid valve on the tank. You may get a bit of gas escape, which will be pressure in the pipes.

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Second photo looks like a solinoid.

There should bea solenoid etc the tank and another under the bonnet, which is in pic 2

Well I have found the vapouriser online but out of stock https://tinleytech.co.uk/shop/lpg-p...ion/bigas-ri-21-sgis-double-reducervaporiser/
So looks like spares might be available.

Andy Burrell said:

Well I have found the vapouriser online but out of stock https://tinleytech.co.uk/shop/lpg-p...ion/bigas-ri-21-sgis-double-reducervaporiser/
So looks like spares might be available.

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I have that one if i recall the number. The spares kit is no longer produced, but a more modern kit contains o-rings and the diaphragm, the rest of the kit didn't fit.
As my vapourisers have done many miles, i would have been better just buying new versions instead of just the kit. Worth seeing what condition yours are in but I'll bet they are similar as mine

That sounds positive, I will just collect as much info as I can before taking it apart. I assume that there are some electronics somewhere. I found a link to a laptop program showing parameters don't know if the software is still available. The more I can do my self the better.

an overall pic of the engine would be useful

Here are a number of shots of the engine bay.