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[berserkerboy]

Have had an issue with the Stag AC LPG side of my car for a while. I manually change over to gas after a mile or so as in auto mode it seems to change over too quickly. The system was installed by Profess Autogas and I am not sure they plumbed in the water heater side of things very well. This method seemed to work well for a while after I acquired the car.
However, I soon started having issues where the car switched back to petrol and the green light on the switch over would blink rapidly. (More rapidly than it does prior to switching from petrol to gas) I am assuming this is the gas ecu saying there is a fault? Sometimes I can get the car to run back in gas for a while by constantly switching back and forth between petrol and gas.
Profess tried to fix the problem saying initially there was a sensor issue and then that the injectors needed replacing after that didn't cure the problem. I spent quite a bit with them and they wanted over £250 to change the injectors. I don't do much mileage and that would buy quite a bit of petrol before I broke even. In any case I think profess are trying to rip me off as the injectors are cheap Valtec.
My main question is can I change the injectors over myself or do I need the diagnostic software to get the gas delivery right?

[Kevin Wood]

It doesn't sound like the injectors to me.

Switching back to petrol is normally down the vapour pressure dropping, although it can be triggered by other errors. Vapour pressure will drop when there's a restriction in the supply of LPG or the vapouriser is not getting hot enough, so your suspicion that they haven't plumbed in the coolant feed to the vapouriser properly might be a clue.

The Stag software is freely available to download, so I'd get hold of that so you can diagnose what's happening.

[Migv6 le Frog Fan]

I had a similar problem with mine when I first got it, its also a Stag system. The coolant plumbing had been done wrong (cant really remember the details now, but I believe it was the wrong side of the HBV ?), and reworking it to give a constant supply of hot coolant solved the issue.

[tigers_gonads]

Agree with Kev

Get yourself a lead and download the software and check the parameters but your first port of call is to trace the hot water feed to the vaporiser 

You will probably find that's its a hot water issue but I will bet my life savings (that £3:50 by the way  ) that the vaporiser pressure will need tweaking first then the LPG map afterwards 


Oh yeh, don't give anymore money to friggin cowboys who rape your arse by changing every component until it a sort of works 
So called professionals eh 

[berserkerboy]

Anybody know what interface I need?

[05omegav6]

Anybody know what interface I need?

Depends which ecu you have... 300/300+ etc... should be clear on the ecu itself, then order accordingly

[berserkerboy]

Thanks, I'll have a look.

[Lazydocker]

Have had an issue with the Stag AC LPG side of my car for a while. I manually change over to gas after a mile or so as in auto mode it seems to change over too quickly. The system was installed by Profess Autogas and I am not sure they plumbed in the water heater side of things very well. This method seemed to work well for a while after I acquired the car.
However, I soon started having issues where the car switched back to petrol and the green light on the switch over would blink rapidly. (More rapidly than it does prior to switching from petrol to gas) I am assuming this is the gas ecu saying there is a fault? Sometimes I can get the car to run back in gas for a while by constantly switching back and forth between petrol and gas.
Profess tried to fix the problem saying initially there was a sensor issue and then that the injectors needed replacing after that didn't cure the problem. I spent quite a bit with them and they wanted over £250 to change the injectors. I don't do much mileage and that would buy quite a bit of petrol before I broke even. In any case I think profess are trying to rip me off as the injectors are cheap Valtec.
My main question is can I change the injectors over myself or do I need the diagnostic software to get the gas delivery right?

And there's your problem

Start with the basics... Read the guides and check things out

[Shallow Al]

I went to them, and all was well for a while. But then it played up, as you have described.
The coolant plumbing was wrong. I re-routed it as per the guide on here, and all was fine.
Then after about a year, the injectors failed. They were cheap copies of Valteks, and the seals in them broke up. I bought a Valtek repair kit, retuned with the software from the Stag website, and that sorted things out for a long time.
Another thing they did wrong was not fitting clips to the rubber injection feeds at the inlet manifold nozzles. The pipes were just pushed on. This was fine for a long time, but eventually the plpes went slack. Only found out by accident and fitted clips.
Seemed fine when they did it, and car ran well for a while. It was fitted in the summer and did not play up until the colder weather.
I lived in London at the time so, was not going to take it back.
You could say they did all the hard work, but, I don't think I will ever go back.
This was on my previous car, a 2.0 litre 4 pot. My brother in law still runs it now.

[berserkerboy]

Thanks everyone. I will take a look at the hot water connections and get the software downloaded. I only have an old xp laptop as we now use a desktop. Will I be able to put the software on that or will there be complications with it only being 32 bit?

[Entwood]

Thanks everyone. I will take a look at the hot water connections and get the software downloaded. I only have an old xp laptop as we now use a desktop. Will I be able to put the software on that or will there be complications with it only being 32 bit?

IIRC when I downloaded "SetupAcGasSynchro" to help someone out at the Reading meet it worked better on an old laptop running XP than it did on the new one ! I seem to recall that a "proper" Serial port rather than a USB/Serial interface made life somewhat easier .. but it was some while ago now .....

[Kevin Wood]

The AC software should be fine on XP.