I have a 7FGCU32 that I was told is very similar to the 7FGCU25, this is a LPG model. The problem started as the truck would run but if it died we would have to pull the LPG line off the tank to release pressure then it would restart right away, but it still ran but the rpm's had to stay up using the throttle so it wouldn't die, if it died we had to relieve the pressure again. So I was told it was the regulator, so I removed and I rebuilt the regulator, which cured that problem, now it does start back up without having to disconnect the tank, but it idles rough and after a bit wont idle on its own.... if you keep it running with the throttle in neutral it seems to rev up and run great, but if you put it in forward or reverse it loses pawer and can not make it up even the smallest incline... it can move itself along on flat concrete but with little power. After getting the service manual, and understanding it a bit, I see that the OPS light is flashing 2 times then stays on then flashes again.. Turns out there is a sensor in the seat that is not hooked up, I see the wire going to it, but I believe the seat was replaced prior to us getting the lift and there is no sensor in the seat... now the manual says the problems I have are similar to those I would have if that sensor were bad or no one was sitting in the seat, due to the fact that it runs good when in neutral.... does anyone know how I can bypass this sensor? or if there are any other adjustments on the regulator or carb that I can try?
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add this all together ----> Chadillacmicah at y ah oo dot com THANKS
add this all together ---> Chadillacmicah at Y ah oo dot com
Post your email. You gotta be a little cryptic and spell out @at.dot etc
I dont know if I would say it improved when I removed it, maybe when I plugged it??? I can seem to get it to run and idle on its own with it plugged into the box. When I do get it to run it seems to be when its cold, but when it warms up then the smoothness goes away
If performance improved when you removed the hose you need to remove the large tamper plug on the carb and adjust the power valve. Something else you should check is the condition of the spiral wound fuel hose that goes from reeg to carb. If it is rubbed or soggy anywhere replace it
Actually I see what you mean now, the big cover thats held on by 4 screws and the nipple is pressed into that cover... so yes.
Well yes and no on the hose, I believe we are talking about the same hose, but it is not attached with screws, it is a 90 nipple that is pressed into the aluminum casing. I am putting my finger over the hose that is attached to that 90 angle nipple. It does go to a plastic box that is pretty close to right under the regulator. Is there a way for me to post a pic on here? maybe copy and paste? or doesnt that work
Chad, the hose that leads to the plastic baffle box is just a vent that allows the secondary chamber diaphragm to move inward whenever the throttle is opened allowing intake manifold vacuum to act against that secondary diaphragm.
When the intake vacuum pulls against the diaphragm, the diaphragm presses on the secondary valve lever which permits fuel to be drawn to the engine through the large rubber fuel hose to the carb.
The fact that you can notice a difference in how the engine runs when you remove the venting hose from the picture probably indicates there might be a defect in the secondary diaphragm.
Let me make sure which hose you are actually covering with your finger........you are referring to the hose that connectes to a 90 degree nipple on the bottom of the 4 screw secondary chamber cover, is this correct?
And when you cover something with your finger.....are you covering the rubber hose end or are you covering the 90 degree nipple opening?
Rick, THis morning I was going to rebuild the carb and realized that when I saw the carb bolts that hold it to the intake they were both loose, maybe one full turn each, enough that I could move the carb around on the base. therefore creating a vaccum leak I assume, so I took the carb off and cleaned it up and re installed it. I then took the hose off going to the plastic box and it fired up and idled ok, I put my finger over the end of the hose and it smoothed out quite a bit, but when I would give it throttle with my finger over the hose it ran crappy and I had to play with it a little to get rpms up, (nothing too bad, I am just used to a very responsive throttle) I just had to feather it for a second, if I gave it throttle without feathering it , it would kill it. it was idling smoothly with my finger on but if I took my finger off the hose then it would sputter and die. So I am assuming it has to due with the power valve you had mentioned?
Also I took the plug at the top of the regulator out and removed that mixture screw, cleaned it off and screwed it in snug and then backed out 2.5 turns. I screwed that in and out while it was running smoothly but it did not seem to effect it at all, maybe the fine tuning should be saved for last :)
idle and starting for sure but not higher rpm's. did you remove the hose at the bottom of the reg? your symptoms are very similar to power valve issues. this hose will be connected to a plastic box (most likely under the battery). the power valve on that truck is behind the large tamper plug in the extrusion near the base of the carb, it points to the outside of the truck (away from the valve cover) the same procedure for removing the plug except this one will require larger holes and sturdier tools to pry with. what's your (e). as for custom bikes -v- forklifts....chrome exhaust trumps chrome cylinder rod every time. i'm just sayin
@ Rick C. I turned the lift truck on , the lbs at the 1/4 in hose went down to 5 1/2 and stayed there as the truck turned over/ran. I screwed the screw on the carb out, and played around with it and it still did nto effect it at all. I have not rebuit the carb as of yet. I will pull it off tomorrow and clean/rebuild it. As for the small plug at the top of the regulator, I am in the process of removing that and adjusting it, after a rebuild is it possible that that screw behind the plug could effect the idle and power when in forward or reverse?
Thanks everyone, I am no forklift mechanic by any means... I guess cause someone heard I build custom bikes for a living it was assumed by them I could do a forklift with my eyes closed...LOL
Out is higher. Have you pulled the carberator and cleaned it out? I would also check the intake runners because they can get clogged up too.
It is in fact a slotted screw, no matter which way I turn it, it doesnt seem to affect the idle, is out higher idle, or in?
since it's got a seat switch i assumed it had OPS which would mean it also TWC which has a sealed power valve. but your're right, if there is a large hex on the carb, it would be the power valve and would be the adjustment for the main fuel volume.
Is the big screw a hex bolt or a slotted screw? If a hex than that should be the power adjustment on the carb and if you turn it out I believe it will increase the fuel for the power end. The slotted screw on the carb is for idle.
the big screw is for idle. there is a small screw under the cap at the top of the reg. you have to drill a small hole about.125" below the top of the extrusion. use a small pick or allen wrench to pop the plug out. turn the screw in till it stops and turn it out about 2.5 turns. try to start. turn.5" at a time and continue to try starting engine until it starts and idles. then try to adjust it and the big screw till it runs good. once its idling you can try disconnecting the hose on the bottom of the side with 4 screws. if performance improves you can plug the end of the hose and leave it off....do not block it and put it back on the reg...if you want to fix it right let us know. it requires another much larger plug to be removed. 7 pounds is too much. the pressure needs to be 5 or below. put the guage back on and accelerate the truck (simulate loaded condition by using hydraulics) if the pressure drops rebuild again if not we're back to the hose.
The big screw on the side of the carb... How far should it be out, they messed around with that and now I am not sure if it is out too far or in too far...... That is the idle right?
I just removed the fuel hose, there was no pressure when solenoid was unplugged so I tested the 1/4 line at the top of the regulator per your instruction, there is more than 4 lbs of pressure, probably more like 7-8 with the meter. I am not sure if this has an electric throttle, I want to say no it doesn't because I see the cable at the carb and it has the same play as the pedal does I will go out and check if there is more or if the cable goes right to the pedal or to a electronic box. They say it always had power and didnt lose power like it does now, the reason for rebuilding the regulator in the first place was because the idle was horrible and you had to keep it running, if it died then you had to disconnect the LP and reconnect then it would start back up...or you could wait.. it was like you had to relieve the pressure...
i just niticed that this truck is a 32, does it have an electronic throttle? there could be some issues with the "power valve". it's hidden under a tamper plug but can be accessed. to test remove the hose on the bottom of the regulator that connects to the (outside) cover. if your performance problem improves let me know and one of us will guide you through removing the plug.
I would also check the carberator and in manifold. I have seem them build up with sludge up and cause problems.
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