Running Bi-Fuel Fords on Gas

[Airliner]

I know that bi-fuel Fords have the sticker saying they should be run on at least 1 tank of regular gas every 60 days. My question is should that be 1 tank straight through, or run it on a few gallons every so often, totalling 1 tank every 60 days. Does it matter? I much prefer to just use the gas when I run out of CNG for 15-20 miles, then switch back. Is it better to use 1 full tank straight though? Anyone know?

[David Burklin]

Re: Running Bi-Fuel Fords on Gas

Good question. I hadn't seen the "run on gas" warning for my F150. I'd like to know the answer on this one as well.

[Airliner]

Re: Running Bi-Fuel Fords on Gas

Mine is right by the steering wheel, opposite where the ignition is. I have a 99 F250, but I have seen it on several 150's too.

[Yroc]

Re: Running Bi-Fuel Fords on Gas

From the checking I've done, you don't 'HAVE TO' run any gas through the engine. It is probably smart to run a little to keep the injectors and other fuel system parts from gumming up, but I don't think that CNG will hurt the engine at all. I have a frind who has 200K with all CNG and no problems, so I run as much CNG as I can.

i've always wondered if the bi-fuel F150's start on CNG when in CNG mode? Does anyone know. I've been wanting to remove the fuel pump fuse and see if it will still start.

[David Burklin]

Re: Running Bi-Fuel Fords on Gas

From the checking I've done, you don't 'HAVE TO' run any gas through the engine. It is probably smart to run a little to keep the injectors and other fuel system parts from gumming up, but I don't think that CNG will hurt the engine at all. I have a frind who has 200K with all CNG and no problems, so I run as much CNG as I can.

i've always wondered if the bi-fuel F150's start on CNG when in CNG mode? Does anyone know. I've been wanting to remove the fuel pump fuse and see if it will still start.

I don't know for certain, but I believe they do. My truck needs a slight mash on the gas when starting on CNG, and fires right off when running on unleaded. I assume that's due to the lower BTU power of NG vs unleaded. Somebody who's more technically informed feel free to correct my assumptions.

[MiataMike]

Re: Running Bi-Fuel Fords on Gas

Yes, the Bi-fuel 150's start on CNG when in CNG mode. But you can't pull the gasoline fuel pump fuse because GFI piggybacks the CNG tank valve circuit on the same fuse.

[rtry9a]

Re: Running Bi-Fuel Fords on Gas

We are fighting two problems- the cng does not lubricate the valve stems like gasoline does and it probably washes some lubricants away from them. The other problem is that gasoline decomposes (oxidizes) over time and forms a varnish which plugs injectors.

I personally run a few gallons of gasoline periodically, like weekly, to lubricate the valves and add injector cleaner to keep everything clean. There are preservative additives that are also a good idea if you dont want to run your precious gasoline through and store for long periods (like several months at a time).

[ijustride]

Re: Running Bi-Fuel Fords on Gas

I'd assume it's so the gas doesn't go bad, if the injectors get pluged I don't think it will affect the CNG injectors. From a visual inspection I think the gasoline injectors are on top of the CNG inlets, thus bypassing the gasoline injectors. I havent run more than 10 gallons through mine in the past year.