[Clan]

Originally Posted by John Mawson

Hi.
V50r
2.4i
2004
214,000km
Lpg added 2016

I've had the code p0172 since I owned the car for18 months now.

other codes include P0300, multiple misfire and P0137 o2 sensor voltage low (first time I saw that one)

Parts I have replaced.

Sparkplugs with 1 electrode
Air filter
MAF sensor
Lambda,2
Throttle Body, Oem.
Battery.

At first when I got the vehicle it had a hard job driving at low revs and giving throttle, like out of a roundabout, so I would have to shift down to alleviate misfiring, after changing the spark plugs it,s 80% better.
I think the problems are associated with the LPG side of things.
I went to an LPG mechanic and he did something ? for 200 euros so
Idling on petrol or lpg is really steady now.
The engine lamp is still on. I use the Volvo every day and it seems to drive fine but one thing I now do is to turn the Lpg off until the engine temperature shows 90 as in cold weather the Lpg switches over to early and I get a warning to switch the Lpg off, so I wait a few more km before switching over.
I don't think I have a vacuum leak, I tried an improvised Smoke test and didn't see anything obvious.
I have a screen shot of the LTFT reading -23.4, so that's quit bad from what I have been reading STFT was 10.2%
engine speed 721
MAF 4.02
Time since engine start, 26 sec, which means its on petrol.
Fuel system 1 status CL which I think means closed.

I really don't know what to do, Mechanics don't like Lpg and Lpg mechanics don't really mess with engines.
If I found a Volvo Mechanic they'll probably charge me 300 euros to tell me to find an Lpg mechanic, that's my fear anyway.
Anyhow I hope someone has an idea about this.

you will probably find the LPG exhaust gasses are very different to the petrol gasses which the lambda sensors are used to, so the reading will not be what the ECU expects. does the engine light stay off when on petrol?