CNG only to dual fuel conversion?

The other week I drove past my favorite auction place and they had a huge fleet of 2000ish Ford fleet trucks. Looking them up online to bid I saw that they were CNG, I did not notice that they were CNG only until the auctioneer said something about it.

In AZ, if you have CNG capable vehicle, you can get a HOV plate and run by yourself. Without knowing what it will take, I passed on 30 F150's that all had between 60-90k going for $1300-2200 depending on paint and if they had the lift gates or not.

for future reference, does anyone know what it would take to convert to dual fuel? I would convert to gas only, but I wouldn't want to fail inspection and loose the plate.

I recently learned this summer that in Brazil, many new vehicles are set up to run on (3) different types of fuel. I forget exactly what the 3rd is (gas being first), but I'm pretty sure that CNG was one of them. Could be a place to start looking.

Iirc those f150 cngs have a high gvw for that era. 7700 lbs or something. Good in town hauler me thibks. There was something about some expensive valve going bad on them.

Wish my memory was better.

Edit. Google says. Yes they are dual fuel if they are factory conversions.

bluej wrote: I recently learned this summer that in Brazil, many new vehicles are set up to run on (3) different types of fuel. I forget exactly what the 3rd is (gas being first), but I'm pretty sure that CNG was one of them. Could be a place to start looking.

The 3rd is probably ethanol...so it's really like a gas/CNG dual fuel conversion but the gas side is flex-fuel.

In reply to bluej:

Brazil uses a ton of ethanol, and has been for ages, it helps that sugarcane grows like a weed there. Makes corn ethanol production look stupid.

Re: The CNG powered trucks, converting to gasoline may not be cost effective, check and see if those trucks even have a gas tank in them. They probably have a CNG bottle where the gas tank should be, and no gasoline related parts at all. It may even have a completely different intake manifold.

When I found the ad for my Crown Vic it said the Vic was a CNG burner, but it's just gas. It piqued my interest in having a multi-fuel vehicle but I have yet to do any real research.

That's all I have to add, lol.

OK so without knowing what it will take, converting a CNG-only vehicle to dual-fuel is a lot like converting a gasoline vehicle to dual-fuel, with one difference: Normally you'd have to buy the dual-fuel parts and CNG fuel system, this time you'd have to buy the dual-fuel parts and gasoline fuel system (which has probably been stripped out with the CNG fuel system put in its place).