Holden Rodeo Problems

There are a number of LPG systems available for diesels, but they’re different from those we’re used to on petrol engines. In the case of the diesel system an amount of LPG is substituted for diesel, the engine never runs on LPG alone, and the effect of that is to increase power. The idea is then that you back off the throttle and save on fuel, but some people make full use of the extra power and can suffer engine failures as a result. I would urge caution and certainly urge you to talk to other owners who have done the same conversion you are considering to get their experience. It’s also crucial to have an experienced installer do the work on your car.

Everything has a statutory guarantee with it that covers the goods as sold. That you installed the engine yourself shouldn’t have any bearing on the guarantee, unless it can be shown that you have done something to cause the fault. In your case it would seem that is not the situation and the problem is with the engine as supplied by Holden.

That's not just bad fuel economy, it's bloody appalling. It would appear to be running very rich from your description, so I would fit an oxygen sensor if it doesn't have one. If it does it would appear that it's not working.

We are told there can be problems integrating LPG systems on the Rodeo. Our advice is that with an early central point mixer type system the car’s ECU can be picking up an oxygen sensor signal that is at variance to the normal signal when running on petrol. Later injection systems don’t suffer from this problem. To sort that out you need to take your car to an LPG specialist. Also check the obvious, that your car is tuned correctly.

The Rodeo has a known issue that can cause the petrol consumption while operating on LPG, as you describe. You need to take it to an LPG mechanic, preferably one who knows the particular system fitted to your vehicle who should be able to fix it.

It's odd that Holden's diagnostic equipment failed to find the problem oxygen sensors. In any case it is good to get an outcome, and it's something any other owner with a fuel consumption problem should think about checking.

Holden cancelled its LPG development program on the Alloytec engine in the Rodeo when it couldn’t make the valves and valve seats of the standard engine live long enough on gas. While Holden uses the Alloytec engine in its dual-fuel Commodore it’s fitted with hardened valve seats and valves in that car, but for reasons only known to Holden it couldn’t or wouldn’t fit the dual-fuel engine in the Rodeo. Talk to an LPG specialist about the conversion as some claim they can do it quite successfully, but approach it with caution.

Holden walked away from dual-fuel in the Rodeo after they fitted the Alloytec V6 engine because it was too complicated for them to fit the LPG-compatible engine on the production line in Thailand, but local converters have been doing the conversion without any problems. Have a reputable brand of LPG system fitted by a competent installer and you shouldn’t have any trouble.

It would be possible, but I wouldn’t recommend doing it, as there’s too much work required. I would recommend converting it to LPG, you’ll get the savings and it won’t cost you anything like as much. Use a good quality sequential LPG injection system, and check the general condition of the engine before making the conversion.

Holden switched from the Isuzu 3.5-litre V6 to the locally produced 3.6-litre Alloytec V6 in 2006. The fuel economy was claimed to have improved by around 2.5 per cent in the switch.