While in the Altiplano of Bolivia we got some poor quality fuel (see the full story here).  Whilst filling our tank from the jerry cans, I noticed there was some wax forming on the jerry can spout’s mesh filter. Hmmm… not a good sign. The fuel was only at about 4C; it was going to be much colder in the morning… likely to get waxed fuel!

Needless to say, the following morning with -18C at 4100 m, the fuel in the tank had waxed. The engine wouldn’t start!  The engine pre-heater also refused to start due to the waxed fuel, although it had worked at higher altitudes than this when it had good quality fuel.  Using my multi-meters thermal probe, I checked the temperature of the heaters in the fuel filters and using my EASY I checked the ECU. It seems the ECU had decided that it was not cold enough to turn the heaters on!?!?!? A few choice words for the Bosch/Iveco software engineers fell frozen from my mouth in the cold.

A quick bit of research revealed that the heaters were controlled by relays T19 and T30/31 (yet another Iveco documentation screw up: the drawings show relay T30 and the text refers to relay T31 – nice one).  I pulled the two relays and inserted a couple of short wires with male spade terminals, effectively ‘turning the relays on’.  I turned on the ignition for 3 mins to allow the heaters to warm up (which I checked with the multi-meter thermal probe). Then I tried to start the engine – success.

The heaters are great. In 3 mins at -18C, they defrosted our completely waxed-up fuel filters and the engine runs well. Shame I had to use shorting links to get them to work!  I will work on a switch to enable the relays in the future. (Note: When you pull the relays you get a ‘check engine 114’ warning and the red EDC light. I checked it with the EASY, it’s just telling you the fuel heater relays are open circuit, as you have removed them and the ECU cannot sense the relay coils).

Update – I have now installed a manual override switch for the fuel heaters (see here) and an indicator light so that I can see when the ECU turns them on.  It would appear that the heaters are controlled correctly by the ECU below 2,000 m.  I therefore suspect there is a software bug in the ECU.

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