Engine cut out & P0032 lambda sensor

[JTG]

Hi all, new to the forum and to Volvo ownership. Also my first LPG but I'm picking things up quickly. I really like the car but it has one very telling issue that I need to rectify immediately, as the car is only going to be used on dual carriageways/motorways.

The S80 bi fuel I've just bought has a fault whereby the engine cuts out on LPG, so far only when slowing or stopping. It has done this three times in the space of about 80 miles.

Now I know it is not uncommon for the bi fuel's to cut out, but mine otherwise runs perfectly fine (no misfiring). The only other issue the car appears to have is that when I lift off or feather the throttle between 50 and 60, the car can judder a fair amount. It can also take quite some time to restart it, but I assume this is down to there still being gas working it's way through from when it cut out (I will be checking spark plugs at the first opportunity).

When the car does cut out, it triggers the engine management light and throw up the code P0032 which which appears to be the O2 sensor bank 1 sensor 1.

So my question really, is what are people's thoughts on the likelihood that replacing the O2 sensor will resolve the issue? I can also find very little information about replacing the O2 sensors (other than how important and difficult it is to obtain the correct one), am I right in thinking hat bank 1 sensor 1 is in front of the CAT and easy to replace?

I intend on cleaning both the MAF and the throttle body soon to rule those out as possible causes of the juddering.

The car has been well looked after and possesses a full service history and the LPG system was serviced in December (I don't know what this serviced consisted of).

Also on a side note, I assume it's not unusual to be able to smell gas to a small extent in the engine bay?

Thanks for any help

[classicswede]

It will not be the lambda sensor

First thing to do is to give the stepper motor a good clean. Next step is to strip the gas solenoids and give the plungers on them a clean

[JTG]

Originally Posted by classicswede

It will not be the lambda sensor

First thing to do is to give the stepper motor a good clean. Next step is to strip the gas solenoids and give the plungers on them a clean

Thanks for the response, that's what I had feared. I have no experience with the LPG system but it sounds like that's very much a DIY job.

The best information I can find about cleaning the stepper motor is in this thread: http://www.volvoforums.org.uk/showth...+stepper+motor however is anybody able to advise me on where the stepper motor is located? There is also advice saying to do it by disconnecting a pipe and pouring some injector cleaner into it but again, I have no idea which pipe this would be.

Thanks again for any help

[JTG]

Ok, so.......

A piece of info I've got is:

"Get a bottle of STP fuel injector cleaner, disconnect the pipe from the dryside gas filter to the distributer. Pour about half the bottle of cleaner into the pipe and refit the connector. Run the car until it switches to gas, the engine will stall. Leave the car overnight, if you need to use it switch it to petrol. Start the car after a few hours (I usually left mine overnight) and let it switch to gas - the car will cough and may stall but will soon settle to a nice idle after the excess cleaner is cleared. Bob's your uncle!"

Is this accurate or do I actually need to take the stepper motor off? if this is correct then could somebody please point out which pipe this is?

I have managed to locate the stepper motor (picture attached for reference as images for these seem to so few and far between)

A couple more pictures in case the pipe I require access to is on one...... Is this the distributor?

Final picture, just curious about what this part is? Looks a little bodged...

I have some injector cleaner and desperately want to try to resolve this as soon as possible, just want to try cleaning it before I purchase a new stepper motor.

Thanks again

[JTG]

I want to say the first image is the stepper motor with the distributor underneath it, the second picture is the vapouriser and the third, a filter coming from the vapouriser (which looks old), is this pipe the one I need to take off and pour injector cleaner in?

[classicswede]

Top pick is the stepper and distributor unit
Second pic is the vapouriser
Third pic is the vapour filter

As far as I know STP do not make a LPG injector cleaner. Cleaners for petrol injectors can cause damage to the seals of LPG components
Never use brake or carb cleaner

The correct thing to use is IC12 injector cleaner

[JTG]

Thanks, I've just bought some IC12.

I made an educated guess which pipe to go for yesterday and used the injector cleaner which does seem to have things running fairly well so far. I will do the same again with the IC12 when it arrives and hope that my issues are resolved without having to start getting new parts for it.

[JTG]

I'm still having issues with LPG. Today the car actually cut out while accelerating and would then stall each time I tried to switch back to LPG.
I've since started the car again and it's switched over to LPG again ok.

I do have one strange symptom which might help with diagnostics... When idling on LPG and I blip the throttle, the revs will stick and won't then drop any lower than 1500rpm. If I blip the throttle to 2500rpm or 3000rpm, the revs will very gradually decrease back down to 1500rpm. Idles fine on petrol at 800rpm and normally idles the same on LPG under normal driving. Has anybody experienced that before or have any idea what would be causing it?

[classicswede]

Next thing will be to strip and clean the solenoid. Check the solenoid coil as that might need replacing

[classicswede]

Also check the vaporiser is not leaking gas from the vacuum port