I Am interested to know what is involved in converting my CNG dedicated truck back to gasoline. It is a 1997 F250xlt with a 5.4.
Right now its a bit of a junker and needs a lot of stuff to ever get back on the road but I'm willing.

 

If it is CNG only you have a lot of changing to do.
1 The PCM program is not correct for Gas.
2. The CNG fuel is from a pressure regulated tank. Gas comes form a regular tank with fuel pump and it's control system you would need to add.
3. The intake manifold likely has to be changed over for Mass Air, EGR, throttle body, IAC and a host of items to get the system to work code free with correct harnesses installed.
.
I would reconsider the project from a 'worthwhile' stand point of cost, time and hassle for the end result that may or may not be successful.
Sure to be a good learning experience but is it worth it?
Good luck.

 

Thanks for the fast reply.
I got the truck for free and now i am starting to see why LOL. The truck sat for 7 years outside and trees were growing up through the bed LOL
Seems like a lot to solve so i guess i need to come to a desicion one way or the other. I don't mind getting into it and would do all the work myself but i guess i will have to do more research on the parts availability and costs. There are numerous CNG parts i can sell off the truck to help offset costs if i decide to go this way. At this point i am still learning my way around the truck and finding out where everything is. I am looking and planning at a couple of years to tear it down and build and it has been up on jack stands for a while now.
Recently, like last week i started pulling the front end apart to get down to the rusty bits that will need to be dealt with.
So far i have found that the core support, both rockers and perhaps a bit of the floor pan have substanial rust so im looking to replace and weld in those parts. Fortunately the parts are quite cheap from what i have found online. If anyone knows of a local spot for body parts in Toronto i would like to know!! Thanks
I am thinking of pulling the drivetrain out completely to inspect and overhaul and basicly make nice. If later it is decided the project is too hard to convert i can always sell the engine and other parts as a back up plan so i have an out.
I should point out this is all a hobby for me. I have a small shop in Toronto where i work on my projects the most recent being a 1997 Hummer H1 that i tore into and restored and customized. That has been done for a while now so im moving on to the Ford which will be a much bigger project. I am shooting for a flatbed version of the BIG RED truck that i found on this forum DROOOL!! I know i have a ways to go LOL
I thank all of you ahead of time for the future pain and suffering i will enevitably put you all through with my endless questions and comments, after all this is my first Ford!!

 

I have a bunch of pics of this mess at the 3 links below showing when i first got the truck, the interior rip out, some parts clean up and finaly what i started doing over the last week taking the front end down for a look see.
I admit its pretty bad and i completely understand why i should give up on this but its either got to drive out of the shop or go out as parts so im diggin in!!
http://greenmeanh1-com.webs.com/apps...bumid=13861758
http://greenmeanh1-com.webs.com/apps...bumid=13870357
http://greenmeanh1-com.webs.com/1997fordf250project.htm

 

I changed my 98 Bi-Fuel to gas only...wasn't bad at all! However, your 250 being dedicated will require much more work.

Good Luck!

 

Well i have been tearing into it a bit over the weekend and got a few things off and cleaned up. I found what appears to be the CNG controller. It was mounted to the front of the rad. There were some other parts attached to the core support that i removed and i dont know what they are except i did identify the horn. I think the frame will clean up OK and i did a little test spot near the front just to see what the result will be. The rust is largely surface only on the frame bits and there is minimal pitting.

 

Here is a link to some pics of what i got done over the weekend or since i started this round of stuff.
http://greenmeanh1-com.webs.com/apps...size=60&page=1
Im ready to start taking out the core support and i have a question. There appears to be a doxen spot welds on each side to drill out and the body mounts need to be removed. Do i need to support the front of the truck/fenders or can i just pull the cort support out?? Probably have to cut thriough the body mounts.

 

Another question if I may. I am trying to remove the windshield wiper mechanism. From what I can see is there is no way to pull the unit out in the rest position so I'm thinking of jumping the contacts on the back of the wiper motor to get the offset arm to clear from under the drivers side opening. There are five contacts on the back of the moter. Which two contacts are negative and positive??? If I can get the offset arm pointed to the pass side I should have the clearance needed to remove the damn thing. I tried removing the snap rings to drop the mechanism out of the mount but it is still connected to the head of the motor. So that didn't help.
Any ideas on this???

 

I got the wiper mechanism out. I managed to turn it towards the front of the truck and got a long 8mm on the motor shaft nut on the bottom and that allowed me to turn the mechanism and align it for removal. I then took it all apart for R&R.
http://greenmeanh1-com.webs.com/apps...size=60&page=3

 

Pulled off the front calipers last night and they appear to be in good shape. I am going to replace the pads even though they look ok due to all the fluids they have absorbed in the cleaning process. Tonight i plan on removing the rotors to have a peek at the bearings and re pack them even though they are probably fine.
What is the torque proceedure for the front bearings and rotors??
I found a thing on the firewall that looks like a reed switch of some sort with a large wire going in and out. Can someone tell me what this is??
http://greenmeanh1-com.webs.com/apps...toid=194454581

 

Air induction is now off the truck. Surprised how clean the air filter was!! A lot more space to work now. I slathered some of the suspension parts and the brake resivoir with used trans fluid to eat the rust and soak into the rusty stuff so i can get stuff out easier.
I decided to leave the rotors on for now in case i have to drop the truck and roll it around the shop.
http://greenmeanh1-com.webs.com/apps...size=60&page=3

 

I had spoken to the previous owner of the truck and he said there was no AC and i figured out why. There is no compressor! Looks like it was removed at some point and a delete bracket had been installed. All other parts are accounted for. I noticed the manifold that hooks to the compressor is still there and the 2 holes open to the elements so i assume the whole system is contaminated. At least i wont have to evacuate the AC.
Im probably going to pull everything out back to the dryer and including the cooler which had been rubbing on the core support and may have a leak, I dont know at this point.
Most of the night was spent going after rusty bolts with dexron 3 in prep for later removal. The brake resevoir is about ready to come out. Hopefully i can get the lines off without busting them but i have my doubts.
With pics i have been adding to the list everynight and they are at the same link listed above. There is about 4 pages of teardown pics now. I will leave the link for page 4.
http://greenmeanh1-com.webs.com/apps...size=60&page=4
Things i need
Spot weld drill
Engine hoist
Torque spec for front rotors

 

Dang, that's quite the project! Sorry, I don't have any knowledge of that rig.. I'd think I'd try to find a donner F250 with a gas 5.4 and harvest the drivetrain from that and just ditch the CNG one out of yours... You'll need the ECU from the gas rig of course..

Good luck!

Mitch

 

Progress report for the last few days. I got the Battery Box, Windshield washer tank out so the whole passenger side tray is now clear.
I removed the top tank retaining straps off the cng tanks. I tried to lift one by hand but they are about 275 pounds each. They will need to be winched out by crane LOL
Last night i got the friggin ABS modulator out. Not so easy!! Broke off the front line from the booster to the ABS but all other fittings came out OK. The mount will not come out. The 2 rear bolts just spin so im going to leave it in place.
I scraped away some more on the frame areas around the engine compartment. I did find a small area of frame rot by the upper a arm drivers side. The rear A arm mount has a bit of the flange that rusted out. I smacked on it with the air chisel to see how bad it is and its not through to the frame yet. It will knock a few years off the truck overall but its not a write off and i think the rust can be managed.
I mapped the main wiring harness and i now have a pretty good idea how all the electrical system works. I found a wire on the drivers side just hanging. Green and black wires coming out. No idea what its for. Everything else accounted for. The wiring looks pretty messy a first glance but Ford made it pretty simple. I will probably pull the harness to clean it up and ring it out i so i can draw a schematic for it.
This is all a ton of work but im having fun.
Updated pic file has 233 photos of this phase of the teardown in order. A lot of the pics may not make sense but they are essential for me to be able to reassemble.
http://greenmeanh1-com.webs.com/apps...size=60&page=4

 

Front grille and bumper brackets removed and cleaned up. I got a few pics of the underside and the quagmire therein. All in all not too bad!!
This is all a pretty slow process. I manage to get a few hours in each night after work and my goal is to pull one part a day off the truck and clean it up and pack it away and take pics of the process. So far i am pleased with the progress and have not had any bad days yet. I have only broken 3 bolts thus far and i broke an electrical connector tab on the brake modulator. I expected it would be much worse. When i rebuilt my Hummer which is the same year as the Ford, every single bolt took hours to work out and heat was needed. So far the Ford has been a breeze!! I havent really spent any money yet (free truck) on this and im just using up left over shop supplies that i have laying around from previous jobs. I am at the point where i have to buy some stuff like a spot weld cutter. That would speed up the progress because once the core support is out i can pull the cooling stack out and that will open up the pathway for engine work!!
I added about 20 pics at the end of page 4 and on page 5
http://greenmeanh1-com.webs.com/apps...size=60&page=4
A video i made of some wiring and brake details