99 OEM Propane Dual Fuel E250 Van: Presale Questions

[Looking Up]

I have the chance to buy to buy a 1999 E250 van with a ex-GSA gas/propane dual fuel OEM/GFI conversion still intact on a 5.4 engine.
It seems that most of what I have read concerning the use of propane or at least switching back and forth between fuels is nothing but trouble because of valve failures, difficultly in locating EPA certified techs, the cost and availability of parts, etc.
Still, the price of the vehicle is right, a nearly perfect body and it only has 44K miles.
(1) If the van us run only on gasoline, is having the propane system there a problem or just extra parts?
(2) If it is a problem, are the propane parts add-ons that can be removed or were the original stock parts replaced with the duel fuel parts?
(3) It is my understanding that any Ford dealership tech can work on the gas parts, just not the added propane parts. Is this correct?
Thanks!

[spikedog]

I'm just shooting in the dark here, but I thought propane needed a much higher compression ratio than gas. So I'm wondering how the van can have both systems available onboard. Should be either/or, not both.

[YoGeorge]

Originally Posted by spikedog

I'm just shooting in the dark here, but I thought propane needed a much higher compression ratio than gas. So I'm wondering how the van can have both systems available onboard. Should be either/or, not both.

No idea on the add-on system, or how it can be converted back to gas only, but as for the higher compression ratio, my wife and I rented, back in 1985, a propane/gasoline Opel station wagon in Holland. While driving along, you could flip a switch under the dash, and after a momentary stumble, it would just keep right on going on the alternate fuel.

I remember filling the propane tank, and could have frozen my hand off if I'd been a *little* less careful...just like a giant butane lighter....

I'd just leave the dual fuel system on the thing unless you have issues running it on gasoline only, switching valve problems, etc. Kind of a novelty.

George

[spikedog]

Here's some info I found:

TeleflexGFI is well known in North America for the systems it provided domestic OEM car manufacturers (Ford and General Motors) for their OEM GFI (Gaseous Fuel Injection) dual fuel systems. These systems were not a success (some might say a dismal failure) and were the reason that the domestic OEMs completely dropped their propane vehicles. It has been reported that this is likely the reason that Ford dropped the LPG program, as it was the single highest warranty and customer dissatisfaction program Ford ever undertook!

The TeleflexGFI systems were used on such vehicles as the Ford F150 pickup truck and probably worked extremely well when it was new. Ford integrated the TeleflexGFI system with their OBD II computer system and the Ford computer was flashed to communicate with the GFI Compuvalve (integrated computer and metering valve). Much of the problems with these TeleflexGFi systems had to do with the failure of the key system components. Notably, the Compuvalve and the GFI vaporizer were problematic and expensive to repair. There were generally two leakage areas with the GFI vaporizers. These vaporizers would either leak at the gasket between the vaporizer's two halves or at the first pressure reduction piston seat.To make matters worse, LPG system failures often resulted in a complete engine shut-down and an expensive tow back to a Ford dealership for repair.

Normally, the system starts either on gasoline or on propane. However, there is no way to switch to propane operation on-the-fly once the engine is running on gasoline. This interlock was intended to prevent backfires during switching such as in the case when drivers want to compare propane and gasoline power during uphill, full throttle acceleration. Such switching in the large plenum Ford intake manifold can easily result in an explosive failure.

The system was designed to minimize backfire failures by switching to back to gasoline operation under high loads. Under high loads with a cold engine, propane pressure in the vaporizer can drop and the TeleflexGFI computer is programmed to switch back to gas a predetermined vaporizer pressure set-point. Once back on gasoline operation, the only way to get back to propane operation is to shut down the engine and restart in propane mode.

In addition, to protect catalytic converter from a lean fuel mixture, the TeleflexGFI system is also designed to switch back to gasoline operation when the LPG tank reaches approximately 3 gallons. The Compuvalve estimated the fuel volume by reading the LPG tank sender voltage. If the engine was running in propane mode prior to refuelling, the Compuvalve required the engine to be restarted in propane mode. The obvious problem with this strategy is that a tank sender failure prevented the engine from being restarted in gasoline mode. Sometimes the Compuvalve would fail which would then prevent fuel mode switching or cause a premature switch-over.

The Compuvalve is a proprietary item and is priced accordingly. It is possible to replace this part with one from another manufacturer but this requires some rework to the fuel system. The other alternative is to completely replace the entire TeleflexGFI system with another manufacturer's system (while keeping the LPG fuel tank and the fuel lines).

[HAB]

If you haven't purchased, DON"T, your just asking for trouble with a system no one can find parts for or the parts are ridiculously expensive when found.
Find a regular van. Right now they are all cheaper due to fuel prices.

[Looking Up]

Thanks for all of the information, Skikedog.
I would still considering buying the van if I could get a price and commitment from a certified shop near here for removing the propane system and reprograming the electronics as needed. I contacted BAF in Dallas,TX three days ago but they have not responded. It is my understanding that they have extensive experience with the OEM systems--but that does not help if they will not return calls.