2003 S80 bi-fuel won’t switch to LPG
 

recently bought a 2003 s80 bi-fuel ( wife won’t let me drive the 2.5T anymore) anyway got it for a steel as the LPG system didn’t work , as I said to the wife “how hard can I be ?” Well :
1. Changed the vapourisor elbow and solenoid
2. fitted a new filter
3. Checked fuses
4. Stripped down the distributor , cleaned thoroughly and found a small piece of (possibly O ring ) stuck in the side of the stepper motor , gave it a little push and it popped out , I now know this was not a good think to do .
5. Found a faulty injector and replaced for new .
6. Checked the plugs ( they’re the multi point type ) going to change for bog standard NGK
7. Got plenty of heat circulating around the regulator.
8. Got a click sound from the boot area when operating the switch but not from the solenoid under the bonnet .
9. Tank is 3/4 full and as metioned there’s gas to the dizzy
10 . Screemed “why won’t you work” at it !

I’ve read all the posts a learnt plenty from the guys on here , I’d be happy right now if it just ran a little , even if it was rough , cut out after 10 miles , misfired , backfired or just broke wind !

Autogas 2000 have been great so far and I’d recommend them highly.

Is there anyone out there with any help , advise or similar experience to mine please ?

If the vapouriser solenoid is not clicking then have you cleaned inside it?

If clean inside then try a new coil on it
https://www.classicswede.co.uk/Bifue..._10879079.aspx

It’s clean inside and a bought a new coil from yourselves, there’s no power to it , had a multi meter on the leads and there’s no voltage when the switch is activated (engine hot or cold)

Looks like your might be best replacing teh front end for a propper system

Have you checked the solenoid operation by applying 12v from an external supply to see if it switches?

Cheers for that , I haven’t to be honest I’ll give that a go , that one should activate with the switch along with the rear one (obviously) I was wondering if the temperature sensor in the head would have to send a signal before the front one would operate.

That would make sense, but it's so long since I had a bi-fuel I can't remember exactly how it works and unfortunately the manual I have doesn't cover the bi-fuel, so I can't look at a wiring diagram to see how it should operate.

When mine was faulty, it would switch over to gas briefly before the engine died of fuel starvation, so the theory seems sound.

Ok , wired to 12v it activates with a good click ( don’t why I didn’t try that before) , so the fact I’m not getting power from the system leads me think :
1. Faulty switch ( but if fires the rear solenoid ok )
2. It needs to be up to temperature ( faulty temp gauge )
3. Faulty ECU maybe !
4. Faulty relay ( learn how to check that )
5. Faulty stepper ( not fitted right now, away being tested )

I think that’s my list complete, these are just my workings out, I appreciate guys get cheesed off with folk cribbing rather than working it out for themselves on here but having looked through the forum I’ve seen plenty of rough running and also fail after running issues but not a won’t switch over at all problems as such , could be as classic swede said “new front end “ Just need to be sure I’m not throwing the baby out with the bath water first .

If I remember rightly (and I often don't). The car will wait for the coolant temperature to reach a certain value before switching to LPG, mine used to switch within a mile - the obvious place to switch is the front (or both) solenoid/s. Can't remember where the sensor is though, some necam vaporisers have one in the body, but I think it's deleted in the Volvo installation. You need to check.

Won't be the stepper or distributer as that's after the solenoid.

Yes I’ve been told the temperature sensor on the vaporiser is not used (although fitted to the casing ) I can only surmise at this point it gets a signal from the temp gauge on the head or via the ECU (a wiring diagram would be handy) my local Volvo dealership were reluctant to pass that on to me “oddly” .
I’m working away at the moment so I’ll have another bash on my return , thanks so much for the continuing help I really appreciate it.