FG 140 Losing turbo pressure!!

[thefnswits]

Hi all, this is my first post. I got a new FG with a 9 foot boss v plow on it and just started plowing with it 3 days ago, and Im already having problems. First storm on new years eve I was just driving normally and I got an amber check engine light, which basically put me in limp mode. I pulled over and read that i should sit it for 30 seconds with the motor off and the key in the "accesory" setting for 30 seconds. i did that and plowed for a few hours uneventfully.

This morning I was out and about an hour and a half into my route the turbo just gave up holding pressure under full boost. If I really feather it on flat land and get it going to speed without building much turbo pressure, It will be fine, but once the turbo runs at full pressure for more than about 2 seconds, boost drops off fully and I end up having to downshift. After about an hour and a half of this, I got the check engine light again...shut down, and waited 30 seconds, light goes off, i pull away fine, and then by 3rd gear same thing again. needless to say it took much longer to make my way about town to plow my accounts.

The dealer isnt open til monday and i have another day of snow ahead of me. Is there anything I should look to immediately before I have to go out and run it at no boost for another 7 hours tomorrow??? It has been very cold, could this be a gelling concern??


Mike

 

[haven]

Hi Mike, welcome to ExPo!

If the turbo is losing pressure, maybe there's a leak in the plumbing
that connects the exhaust manifold, turbo and exhaust pipe. The
turbo has a wastegate that opens when pressure gets to a pre-set
level. If you tilt the cab forward, you should be able to hear if there's
an exhaust leak.

Maybe your wastegate is stuck open, or the actuator that keeps
the wastegate closed is broken. The open wastegate makes the
exhaust system louder than when the exhaust gas is running through
the turbo.

Or maybe the flange of the exhaust manifold is not completely flat, and
it warps when it gets hot.

Pure speculation on my part, of course.

 

[Quintin]

It may be a mechanical problem as Haven suggested but the symptoms sound to me more like a fault with one of the many sensors (probably the boost sensor) feeding your engine management computer. I ssume from your description of 'limp' mode that there are electronics controlling your engine. If that is the case, there's not much you can do really and in my experience tracing this sort of fault is a time-consuming and frustrating experience even armed with a computer, the necessary software and a decent multi-meter.

 

[thefnswits]

Well, I got it towed back to the mitsu dealer and they said it was the tank...that mitsu puts a coating in the tank to resist corrosion, but that the fuel eats it away. great planning! Either way they're getting a tank and a fuel pump for it, and Its a fuel pressure issue. I guess the pump wasnt able to supply what was necessary under full boost with all the sediment from the tank throughout the system. anyone else ever hear of this? it's an 07 with only 24k miles on it. This was my first time out plowing and im having problems already...I cant afford to have any more!

 

[whatcharterboat]

Well, I got it towed back to the mitsu dealer and they said it was the tank...that mitsu puts a coating in the tank to resist corrosion, but that the fuel eats it away.

Have never heard this before. Could someone please confirm that the North American spec FG 140 has a fuel tank made by Tokyo Radiator. Thanks.

 

[thefnswits]

yeah sounded a little fishy that there would be ANY sort of coating inside the tank...sounds like a bit of a recipe for disaster...why not make it out of different metal??

 

[thefnswits]

yeah the more i think about this the more i think its BS. I think im going to call another delaer and ask them about this.. Are these truck equipped with OBD II??

 

[Amesz00]

Do you have a boost guage hooked up?
If so, is it making significantly more than stock boost immedietly before dropping off?
If so, then the likely problem is an issue with the wastegate opening; ie it is making lots of boost then the computer is hitting fuel cut (the point at which the computer decides there is too much boost and cuts fuel- thus cutting boost).