Discussion:
Mitsubishi FG15 No start. How to check for fuel

Im working on my little Mitsubishi FG15 and have a no start problem. After a lot of troubleshooting, I found I had no compression in cyl 3. Pulled the head, had it rebuilt and put it back together.

Compression: 120-130psi in all 4 cylinders.
Fuel: New Impco Model J. Tested the 12v actuator and it works and allows high pressure fuel out. Rebuilt mixer. The plunger valve moves freely up and down.
Air: Vacuum lines all look good
Spark: New coil. New plugs. I have spark on all 4 cylinders

Only thing I havent checked is the timing but I cant get it to fire. I dont know how to check that fuel is coming out of the converter. I know it works on vacuum to pull the fuel into the engine. Any suggestions to check that?
  • Posted 2 Sep 2019 08:47
  • Discussion started by Tim_W
  • Texas, United States
Showing items 1 - 7 of 7 results.
Thanks... I got it up and running. It was the 12v lockoff in the end. Swapped it out to a new one and it runs. It needs a little help (quick bit of starting fluid) to get it running but it runs fine when it gets going.

Any ideas on how to keep it primed and not need that 1/2 shot of starting fluid?
  • Posted 4 Sep 2019 09:30
  • Reply by Tim_W
  • Texas, United States
when you turn on the truck and the lockoff powers up and opens the lpg fuel line to put pressure to the vaporizer you should get pressure on the vaporizer, put the guage on the output side. it should have a 1/8" pipe thread plug for it i think. Don't put it on the pressure side or you'll probably break your guage :oD probably isn't a port on that side anyway.
  • Posted 4 Sep 2019 09:20
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
Thanks for the reply.

The forklift has a 12v electrical cutoff instead of a vacuum cutoff. I just got a new one in and Im going to replace it. That will make almost a brand new fuel system (12v lockoff, new Impco vaporizer, rebuilt CA55 mixer). I also go a pressure gauge to mount to the back of the vaporizer to check the pressure on the low pressure side.

Should I see pressure all the time or only when the truck is runinng?
  • Posted 4 Sep 2019 06:59
  • Reply by Tim_W
  • Texas, United States
maybe this model has a filter before the vaporizer? it kinda looks like a vaporizer but is just a fuel lock/filter, should have a vaccum activated valve that turns on the lp when the engine is cranked. If it has a hose running from the mixer/carb to this fuel lock/filter you can pull the hose off the mixer and apply vac to it and it should open the lp fuel. If you remove the fuel supply hose from the mixer you will hear LP vapor coming out and smell it fairly strong.

One other thing to check is the mixer diaphragm, remove the top screws and carefully remove it, check it for tears and dirt, look at the center bullet that closes it off and make sure it is clean and intact.
Clean it up with carb cleaner or a fast drying motor cleaner, do not use brake cleaner, and blow it off. if you find any tears in it replace it.
Then remount it the same way it came off and see if that helps.
  • Posted 3 Sep 2019 14:45
  • Modified 3 Sep 2019 14:50 by poster
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
They done away with the primer button years ago
  • Posted 3 Sep 2019 04:54
  • Reply by alanmitsi
  • essex, United Kingdom
Thanks for the reply. Not sure which vacuum hose to suck on.

The motor is a 4G33. So I got it to run and idle great on starting fluid. So this is definitely a fuel problem. I have a new 12v solenoid coming (though the current one has tested fine and when I jump it, I hear it click). While cranking I can feel a slight sucking on the fuel inlet of the mixer so it seems I have vacuum to pull.

Unfortunately this new Impco converter doesnt have the primer button to see if I can get fuel past it. When the tank is open and the engine is cranking, I smell propane. Im going to replace the hose just in case it has a leak.
  • Posted 3 Sep 2019 02:55
  • Reply by Tim_W
  • Texas, United States
Suck the vacuum line hose should see gas coming through what engine is it a k21 or 4G try a bit of brake cleaner in the intake if it fires then definitely gas problem
  • Posted 2 Sep 2019 23:59
  • Reply by alanmitsi
  • essex, United Kingdom

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