Stefanelli gas system

[tom-madbiker]

Hi I have just got a landrover disco with a stefanelli system fitted I have been into it as I was going to lean it out a bit as it currently does around 10 mpg on gas which seems a little low I was expecting 13 ish round town but I was hoping for some pointers as it's not the same to tune as the king or the AC systems in the other cars it also says it's on semi sequential which I assume is batch fire on the injectors

[Gilbertd]

What year Disco? Disco 1 with the 14CUX equipped motor (the one with a distributor) or the later Disco 2 with the Thor motor with Bosch Motronic? The 14CUX petrol injectors are batch fired anyway so it would be correct, the later Bosch is fully sequential.

[tom-madbiker]

It's the early one I thought they were batch fired have found a stefanelli manual which is helpful but I need to sit down and read it through. What do you get from your v8 I was expecting at least 13 mpg

[Gilbertd]

I'm running a singlepoint with Lambda control and get anywhere between 13 and 16mpg depending on whether it's running around town or on a long Continental run. That's on a 4.0 litre GEMS P38.

[LPGC]

I've worked on loads of Stefanelli systems over the years but it'll be a few years since I last saw one.

One of the most basic tests you can do is check if lambda readings are flicking when running on gas (and when running on petrol). On a fairly simple engine/setup if lambda is flicking the same on gas as it is on petrol there won't be a lot you can do to increase fuel economy... But if injectors are worn some cylinders could still be getting more fuel than others and that can cause increased consumption even though lambda seems good.

[tom-madbiker]

I don't think injectors are that worn it was installed in 2008 but it's only done 30000 since it's got 78000 on it from new when I go into it the lambda reading is no reading so I guess it's not currently connected thing that got me is there is no map per say it just seems to be a multiplier from the petrol injection times

[tom-madbiker]

The badge on it says it was installed by lpg.co.uk

[LPGC]

48000 miles may be enough to have worn out the Stefanelli / old design Valtek injectors.

But how are you measuring mpg? The fuel gauge and fuel computer may not be accurate (perhaps especially on LPG). The best way to find true mpg is to compare how much fuel you put in the tank to mileage, even then (especially with LPG) you'd want to run several tanks of fuel through it to find the average and rule out any partial fills etc that might otherwise effect the results.

[tom-madbiker]

I did it between fill ups but I did not use the same pump I'm not sure mine is all that accurate but it came with the tank so I kept it latest thing is the fuel pump has died so currently on emergency starts on gas luckily it's warm