3B ll, low RPM,s

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Need help please, I've been searching for answers. The truck is a 65 FJ45 and it now has a 3B ll out of a 88 bj75 mine truck. Turbo is a new Garrett GT20, injectors rebuilt, compression 500lbs on each cylinder. I've played with fuel adjustment a little and can only get a boost of 9lbs and EGT of 800 at max of 2600 rpm's. It then shuts down with more pedal left. Pretty sure it is a governor issue, but this my first diesel so I continue to learn. Any help would be greatly appreciated.
Bite
 
I am not familiar with a mine truck 70 series but I would think there is a RPM restrictor (governor) on the engine for safety reasons in the mining operations.
 
I am not familiar with a mine truck 70 series but I would think there is a RPM restrictor (governor) on the engine for safety reasons in the mining operations.

My initial thoughts too,but shutting down an engine is hardly a safety feature.
It would be better to just restrict the fuel and allow the engine to keep running
 
Thank's for your reply's. I figured it was the governor also. The engine doesn't totally shut down, it just stays at 2600 or there abouts. I need to get it up to 2800-3000 for my traffic speed around here. Hopefully someone can tell me how to adjust the governor to get that.
 
Yes new lines all around, new filter and yes it revs to 2600 in neutral. Just feels like other engines like a Cummins I put into an old Ford where the governor comes into play
 
The Aug 1988 FSM for the 3B gives the following info:

InsuffMaxSpeed.jpg

AdjMaxSpeed.jpg

Does that help?

:cheers:

InsuffMaxSpeed.jpg


AdjMaxSpeed.jpg
 
Thank you, but yes I have tried that. It still tops out at 2600 rpm's. Pretty sure it is the governor. Not sure how to deal with it. Increased the fuel a 1/4 turn at a time and don't gain any. Gets to a point I start to loose performance as I can tell from engine sound and egt's drop a little as does the boost.
 
Thank you, but yes I have tried that. It still tops out at 2600 rpm's. Pretty sure it is the governor. Not sure how to deal with it. Increased the fuel a 1/4 turn at a time and don't gain any. Gets to a point I start to loose performance as I can tell from engine sound and egt's drop a little as does the boost.

Well then...... :hhmm:

As a stab in the dark ....

Maybe lighten the flyweights?
Flywheights.jpg


Or if they work against the "speed control spring", alternatively .... weaken that spring?
SpeedControlSpring.jpg

Or maybe just see if the spring has been shimmed out to cut the speed?

Just brainstorming ideas............


:beer:

Flywheights.jpg


SpeedControlSpring.jpg
 
Yea! We're thinking along the same lines. I did take off the governor cover today and study the set up. The shaft o-ring was seeping a little anyway.(needs new O-ring) Kind of hard to figure out how the governor link works,but I'm sure it is from the pressure of the governor sleeve which is forced out by the spinning flyweights. I did measure the thrust clearance and it was .15mm. So by changing the adjusting washer to a min. size and ajusting the protrusion of the shaft back to the min. maybe that would change the distance thesleeve has to travel to shut down the rpm's.
I think you would need a stronger speed control spring and lighting uo the flyweights would be a bit tricky for balance. I considered filing off the end of the sleeve, but chickened out and put the cover back together and had to see if would run. It did once I bled the lines. I've been on pgs FU-40/41
Thanks for the help. We'll get it figured out yet!!!
 
Hey,

don't mean to but in, but just as a note off caution.... before you start altering your govenor, you sure its not restricted in the exhaust,by the turbo? Does the turbo spin up? I don't have one on my BJ but I think it should spin up well before you hit 2600 rpm. Does it feel torqie (is that a word??) before it maxes out? Or is it reaaly just like you hit a rev limiter?
 
Good thought! The turbo does rev. up nicely as I can tell by feel going thru the gears, sounds, and boost guage showing the pressure it builds. Also exhaust is 2 1/2" straight pipe as suggested by turbo guy. Prettty sure it was governed down while used down underground in the mine hauling workers around. Tranny was also banded so just 1st and second could be used in low range in the transfer case which was welded there.
 
Good thought! The turbo does rev. up nicely as I can tell by feel going thru the gears, sounds, and boost guage showing the pressure it builds. Also exhaust is 2 1/2" straight pipe as suggested by turbo guy. Prettty sure it was governed down while used down underground in the mine hauling workers around. Tranny was also banded so just 1st and second could be used in low range in the transfer case which was welded there.

did you get this all sorted out? I’m having the exact same problem with my 3b but it went from being able to rev to 4,000 to only going to 2,500 and my turbo seems to be only providing half its usual boost with the same or above EGT.
 
Did you clean the priming pump strainer and check the main fuel filter (drain water separator). The butterfly flap in the throttle body move freely and follow the fuel pedal linkage. hoses from throttle body to fuel injection pump clear. Might as well have a look at the diaphragm and check that the fuel rack move all the way. No air in fuel injection line.
it happen quickly?
 
Did you clean the priming pump strainer and check the main fuel filter (drain water separator). The butterfly flap in the throttle body move freely and follow the fuel pedal linkage. hoses from throttle body to fuel injection pump clear. Might as well have a look at the diaphragm and check that the fuel rack move all the way. No air in fuel injection line.
it happen quickly?
Yes it was an instant thing, hasn’t been the same since, butterfly valve is good fuel filter is new and clean, accelerator linkage good and the cable is new.
 

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