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Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

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  • CNG F-150
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?



    I have a dedicated '01, long bed, lifted F-150...seeing how ford doesn't make any more OEM build dedicated CNG vehicles anymore (the newer ones are converted), I'm going to keep this forever and just rebuild the motor when it finally locks up, ha

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  • CrazyCobraManTim
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Everyone,

    I know this is a really old thread - thought I figured an update based on some of my 7+ years driving a dedicated 1998 F250 5.4 XL long bed white, former County work vehicle cruising the roads in and about Southern & Central California, and that my info would be found useful (if not mechanically offensive or humorous).
    I bought Bertha the White Whale in April 2008 with about 105,000 miles on it. Fast forward to May 2015, and I have just under 194,000 miles on it, and aside from a single blown spark plug - I've had no major issues (until now). The transmission OD light began flickering 2 days ago, and it's a crap shoot if a radiator flush and servicing of the trans will resolve the issue. I would caveat my experience by saying that I've treated this truck HORRIBLY - from a strictly maintenance perspective. I believe I've completely changed the oil only once per year since purchasing it, instead adding a quart of oil every 3-5k miles when it was thirsty. I've replaced (2) bad COPs, went through (2) sets of tires and (1) set of front disc brakes. Otherwise it's been drive, drive, drive....

    Since my truck is probably worth $1-2k at this point, its probably not worth installing a rebuilt transmission (I have a damaged 1992 Crown Vic worth $1,700 in the driveway with a nearly $3k rebuild transmission sitting worthless to prove my point). So - I guess for about $800 per year, I got some darn good service from the truck!

    Semper Fi!

    Tim

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  • cnghal
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Coneboy,
    The filter/regulator should be easy enough to remove. Do a system rundown by disconnecting the three tank electrical connectors and run the engine till it starves of fuel. Crack/loosen the high pressure connection on the filter (remember, always assume there's pressure) slowly until you can move the hose/connector enough to assure the seal is broken and all pressure has been released. Then do the same on the low pressure hose connection on the regulator (remember, it may still be holding 100 psi).
    Use pinch clamps on the two soft blue coolant hoses and disconnect them (Beware Hot Coolant). Then loosen and remove the three bolts on top of the bracket that holds the assembly to the frame rail. Hopefully you won't need to take the assembly apart. Try putting the filter upside down in a soft jawed bench vise and spray a lot of penetrating oil into the threads and let it soak in for a few hours. Hopefully she'll break loose. When you have it open, check the inside of the filter for debris (Filter works from inside out). Check condition of the filter cup o-ring. Clean threads with a soft wire detail brush and apply a small amount of anti-sieze or assembly lube to the cup threads before re-assembly.

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  • CONEBOY
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Very good info about the sensors. I had wondered where it was.

    This truck spent its entire life in phoenix, so road salt should not be an issue. But undercarriage a bit dirty with soil. (Possible aviation off road use) I used liquid wrench on the threads but did not make any difference. I may have to remove the entire unit. (assuming these two components come off together...coalescent canister & pressure regulator) Is there anything I should be aware of when taking it off? I notice 3 lines out of the regulator, two softer hoses and one hardline, whats the difference? Then a single high pressure line into the coalescent. Is there another filter in the pres reg.?

    Thanks

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  • cnghal
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Mike,
    Glad I could help. Each valve should have 16-20 ohms across the pins.
    I have seen on some aftermarket kit installs that the kit ECU can't source enough current for more than two valves and burnout the ECU's drive circuit. Whenever adding multiple valves to a system, I like to put in an isolation relay and fuse and draw my source from the fuel pump circuit since it passes thru the impact switch, which will kill the system power if an impact should occur.

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  • MiataMike
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Thanks cnghal!
    Your comments gave me the clue I needed to fix my latest failure mode. On my '99 those tank valves share the 20amp fuse for the gasoline fuel pump! So when one of the tank valves failed (dead short) I lost both fuel systems! I'm just glad it happened in my driveway. Drove home one day parked the truck and the next morning no start on either fuel. Found the fuel pump fuse blown. Now I carry a spare 20amp fuse and know to unplug the tank harness if (more likely, when) this ever happens again away from home!

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  • cnghal
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Coneboy,
    Never had a problem with the filter on dedicated pickups or vans, but if your truck lived where they used salt on the road the threads may be fused. It may take removing the filter housing and putting it in a soft jawed vise and a can of WD-40.
    I also forgot to mention before, on the dedicated pickups, the pressure/temp sensors on the bed tanks sit at the end of the line on the rear tank and can collect compressor oil and throw off your fuel gauge.
    The next time you have your system depressurized, remove and clean out the tee and sensors with compressed air.

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  • CONEBOY
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Canister would not loosen! Started bending the corners of the aluminum where you put your wrench.

    I have 108k miles on mine. I also do not have a compuvalve.

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  • maxman
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Another thought....Is the quality really that bad, I had to replace my compuvalve, or it the partly a maintenance issue?
    I notice the sticker next to the alternative fuel switch by the steering wheel says to run a tank, a $125 dollar tank at that, of unleaded through every 60 or ninety days. I'm wondering the effect of us not wanting to run the 'high priced spread' through like it says, especially considering the $.85 we in Utah are currently paying.
    Granted, the compuvalve is an issue on these, but is there anybody who has gone over 100K miles without a CNG system failure?
    Max

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  • maxman
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Would the canister not come off, or not loosen?
    On my F150, the canister would come unthreaded, but not come out. It wouldn't clear the cross member on the frame. All I did, was take a pair or vise grips (or heavy pliers) and grip the edge of the bracket the canister mounts to. It only needs to be pried slightly up and forward if I recall. You don't need to bend anything, just flex it slightly and hold it while you pull the canister off.
    Be sure when you replace the filter that you put the canister on straight. If it is off center because it doesn't clear the frame, the canister can split the filter against the perforated tube inside. My filter was split when I took it off and I am guessing that was what happened when someone before me changed it.
    Max

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  • CONEBOY
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    OK I tried that and it worked beautifully. However I never found a bad valve and now my mileage is where it should be... Think its possible that it had a stuck valve that is now working properly? If thats the case I'm guessing it will return. Has anyone replaced a valve before? Cost? Easy to do? Are there better valves than the GFI brand?

    Also while I had the lines purged I wanted to replace fuel filter & clean injectors. This failed miserably because the coalescent canister would not come off! Is there a secret? Normal threads? (lefty loosey, righty tighty) I did manage to get the plug out so I know the pressure was released. Is it common for these to get stuck? What do you suggest?

    Thanks

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  • cnghal
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Simple,
    Each tank has a two wire black plastic electrical connector on the solenoid valve. Each valve also has a large brass bolt with an allen screw in the center. This is the manual shut off valve. The allen screw should be flush with the surface of the bolt and/or turned counter-clockwise until it stops.
    1) With the ignition off, unplug all three electrical connectors.
    Squeeze inside (facing tank) of connector to unlatch.
    2) Start and run engine. After a minute or two the engine should stall and not be able to restart due to fuel starvation.
    A) If the engine stalls, move on to step 3.
    B) If the engine continues to run for more than 5 minutes than you have a stuck open valve. One valve at a time, screw the allen screw clockwise in until it stops. Start and run the engine. If the engine stalls, you've found your bad valve. If not turn allen screw counter-clockwise until stop and move on to next valve. Repeat until you find bad valve.
    3) One valve at a time, plug in the connector. Start and run the engine.
    If the engine won't start or after a minute or two the truck stalls and won't restart then the valve plugged in is bad. Unplug that valve and move on to the next valve and repeat this procedure. Run through all valves at least twice to ensure you have the correct bad valve.
    Last edited by cnghal; 07-02-2008, 08:28 AM.

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  • CONEBOY
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    I have a followup question about those valves in the tanks.

    How can you tell they have gone bad?

    I have a F150 dedicated with 3 tanks (8 gge each?) and I always feel like I should be getting a bigger fillup & more miles between fills. (unless the fuel gauge is wrong... being dedicated I'm afraid to run out! gauge reads 1/8 tank / fill-ups average about 7-8 gge @ 3200 and summer heat) Is it possible that one valve is stuck closed and I am really only using 2 tanks? How would I check?

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  • cnghal
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    Quality?
    The type 1 Faber tanks are almost indestructable. The GFI valves on the other hand, are not. I have a half dozen bad ones in my shop. Most are stuck closed (solenoid coil open or a dead short) which makes it interesting to vent and change valves.

    I agree with Dave on the plugs, but will add that you should use a quality anti-seize compound on plug and O2 sensor threads. I've found especially with bi-fuels (more deposits from gasoline), changing plugs every 50-60k miles and O2 sensors every or every other plug change or when you notice a drastic change in CNG performance.

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  • cngaz
    replied
    Re: Quality of Ford F-150 bi-fuel/dedicated CNG trucks?

    The only probelm we've had with our dedicated 98 Ford PU is a couple of bad tank valves and once in awhile it likes to pop out spark plugs.
    On the Bifuels once they hit 90-100,000 miles, we've had a really hard time keeping them running on CNG.

    Torque your spark plugs properly, not enough threads in the heads and never tune-up until the engine is cold.

    I've had better luck with factory Chevrolet's, easier to get parts for!
    Last edited by cngaz; 05-13-2008, 04:14 PM.

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