Technical Calibration of factory fitted LPG injection

[bsks]

Are you sure there is no LPG ecu located somewhere under your front bonnet? My car has it, but its not a tipo. Also Landi Renzo systems run on 0.95bar gas pressure, injector rail pressure is Gas pressure + map pressure. Rich running on LPG is generally injectors gone bye bye. Assuming you have a landi renzo system, I would look for alternative injectors, because when i bought 4 brand new Landi Renzo ones for 250euro total they lasted 20 000 miles. Try running on petrol a couple of days, if your LTFT goes back near 0 you have problem in the lpg system

 

[FirstTimeFiatDriver]

@bsks

I don't think there is a second ECU. Anyway, the gas system is accessed through the OBD port.

I got the car checked at an LPG shop yesterday. As expected they told me that the injectors need to get replaced. Furthermore they said there is a gas leak in the reducer and I will buy a repair kit for it. (By the way, when switching to petrol the LTFT is normal, near 0. When switching to LPG LTFT goes -30% and the reading of the lambda sensors gets stuck at 1. It is obvious that the gas system is malfunctioning.)

Are you sure you bought the original Landi Renzo injectors? The mechanic told me that there are cheap imitations of them that visually look the same, but they have a very limited lifespan.

Furthermore, are you sure there are alternative injectors that can be used? As far as the mechanic told me there are no other compatible injectors (like HANA for example). The only compatible ones are those from Landi Renzo (and the cheap imitations of course).

As for the pressure that's what I got by reading Fiat's workshop manual (page 47). That the rail pressure should be 0.95 bar + MAP pressure. But to add to the confusion reading Landi Renzo's manual (page 11) I see that 0.95 bar refer to naturally aspirated engines. For turbocharged engines I understand that the pressure at the rail sensor should read 1.2 bar + MAP pressure. So what's the deal, which is the correct setting?

 

[bsks]

I am not sure about the originality of my injectors, i have replaced them long time ago. For alternative injectors, it all depends if you can find a shop which can access the lpg ecu, which is extremely rare. If you can replace them at a shop and get warranty for the labor and parts, then you might be better off doing that.

Edit - Just saw that you have a T-Jet engine, so yes 1.20 bar sounds about right.

 

[FirstTimeFiatDriver]

I am not sure about the originality of my injectors, i have replaced them long time ago. For alternative injectors, it all depends if you can find a shop which can access the lpg ecu, which is extremely rare. If you can replace them at a shop and get warranty for the labor and parts, then you might be better off doing that.

Edit - Just saw that you have a T-Jet engine, so yes 1.20 bar sounds about right.

1.2 bar sounds right, with the exception that Fiat's workshop manual mentions 0.95 specifically for the T-Jet engine (which is the only version of the Tipo that comes with a factory fitted LPG). So we have a contradiction here.

 

[bsks]

I would check what components are installed on your vehicle, specifically the LPG reducer.
Landi Renzo LI10 reducer is set from factory at 1.2 bar - https://hybrid.supply/product_info.php?products_id=6320&language=en
LI02 reducer is set for 0.95 bar - https://hybridsupply.uk/products/landi-renzo/components/landi-renzo-li02-reducer/

Also you can check the manifold pressure reading at idle and subtract the value from injection rail pressure?

 

[bsks]

I meant to say if you can replace the injectors for original ones with warranty, it will probably be alright. My head is off today.

 

[FirstTimeFiatDriver]

The case of the reducer is a specific model produced by Landi Renzo for Fiat. You can only buy it through Fiat's dealerships network. But in fact it is based on LI10, because the LI10 repair kit is compatible with the Fiat's version of this reducer.

There are 2 version of the LI10 reducer: https://hybridsupply.uk/products/landi-renzo/components/landi-renzo-li10-reducer/
The one works at 0.95 bar and the other (LI10M) at 1.2 bar.

The car initially had a gas rail pressure of 1.5 bar, with the intake pressure measured at 0.4 bar when idling, but since I bought it used I'm not sure if that's how it was set by the factory when the car was in new condition. By the way it is well past the warranty mileage and period.

 

[FirstTimeFiatDriver]

Just an update I had forgotten to post.

Landi Renzo has confirmed that the correct LPG injector rail pressure is 1.5 bar.