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Cat 3306B Power Loss/Stalling

Cory W

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Joined
Nov 13, 2022
Messages
35
Location
Upstate NY
I’m thinking it’s a governor issue, as well. The slight wear required in the flyweight assembly to cause that problem is so subtle, it’s difficult to detect unless a experienced Cat guy points it out.
As it turns out I may have found a guy locally who knows cat engines, maybe I'll have him take a look at the governor. Is the governor difficult to remove from the injection pump? As in, can I pull it off of the pump in the truck and not have a bunch of parts fall out? Looks like a few long 1/4" bolts holding it onto the back of the pump. What type of seal is there between the gov. and pump? I got parts to fix my air/fuel control, I'll do that next week just to fix that problem. The governor is about the only thing left to check at this point.
 

Cory W

Active Member
Joined
Nov 13, 2022
Messages
35
Location
Upstate NY
I’m thinking it’s a governor issue, as well. The slight wear required in the flyweight assembly to cause that problem is so subtle, it’s difficult to detect unless a experienced Cat guy points it out.
As it turns out I may have found a guy locally who knows cat engines, maybe I'll have him take a look at the governor. Is the governor difficult to remove from the injection pump? As in, can I pull it off of the pump in the truck and not have a bunch of parts fall out? Looks like a few long 1/4" bolts holding it onto the back of the pump. What type of seal is there between the gov. and pump? I got parts to fix my air/fuel control, I'll do that next week just to fix that problem. The governor is about the only thing left to check at this point.
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,176
Location
Australia
The governor is an integral part of the FIP. Can't be removed as a unit but if access is OK, it's not too difficult to dismantle in-situ.
 

Coaldust

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May 9, 2011
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Cargo Tanks, ULSD, RUG, Methanol, LPG
I’ve never been brave enough to fiddle with one on the engine. I always remove the entire fuel inj assembly and work on the bench or the bilge plates. But guys do it and much respect to those salty fellas back in the days of yore when average men of above average character kept these iron dinosaurs running.
 
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Coaldust

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You will need a Pony 3202 clamp modified like this to remove the watchamacalit spring. The manual explains it. I quoted 16 hours to R&R and rebuild pump & governor back when I was doing them on a regular basis. Not a bad job. I enjoyed doing them.

I keep my Cat fuel system specialty tools in the silverware drawer, next to the pepper sauce. How about you?

96C70C31-BB79-4FB6-A305-C4B45F00CA5F.jpeg
 

Coaldust

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The governor flyweight spring cover is not reusable. Even if you think it is. If you bugger the new one even slightly, the flyweights will jam and the engine will rev to never-never land. But, your mileage may vary.
 

d9gdon

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Joined
Feb 12, 2010
Messages
1,517
Location
central texas
This video shows the separation of the governor on a dozer of the same type as yours, and what you're going to see on the inside.


I'd also take a look at the supply and return fuel lines to make sure that someone hasn't accidentally swapped a line around. Not sure what your history with the truck has been.
 
Last edited:

Mobiltech

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Jan 14, 2014
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Sask.
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Self employed Heavy duty mechanic
Wow that’s a terrible video. I didn’t watch it all but I gather he took it apart to adjust fuel settings which you do not do. Fuel settings are easily done through the fuel setting cover on the back.
I would say don’t touch the governor yourself as it can go horribly wrong if you don’t know what youre doing. Let your Cat guy do it.
If anyone is in the governor make sure you have an intake pipe off and a board to use as a blocker plate for startup in case it runs away.
 

Cory W

Active Member
Joined
Nov 13, 2022
Messages
35
Location
Upstate NY
Yeah I think the internal governor work would be best left to someone who knows what they're looking at. My biggest fear is having to put a new $5,000 injection pump on my 33 year old $9,000 truck. The only parts of the fuel system I haven't directly removed and inspected are the primary and secondary filter bases, and the priming pump. When I prime the system I can feel the primer pump fuel, and I can hear it running back to the tank through the return line. The priming pump does not build pressure though. From what I understand this is normal, the return is a metered orifice back to tank. Something like 7 gal/hr. Am I correct on this?
 

Coaldust

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Thinking more about the symptoms you described and looking back on 3300’s that kicked my butt in the days of yore. I think you might be dealing with a broken guv’nor spring or worn or notched flyweights/pins.

Yeah, there are so many things that can go wrong during the process of fixing one. Having a way to shut down a runaway is critical. Like Dirty Harry said- “A man’s gots to know his limitations”.
 

Coaldust

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That’s the one! Always replace the carrier screws with new. I just remembered that. A small seal driver for the governor shaft seal on the rear housing. Very few special tools needed.
 

Cory W

Active Member
Joined
Nov 13, 2022
Messages
35
Location
Upstate NY
Alright so kind of an interesting update...I got the parts I ordered for the air/fuel control installed this morning- specifically a new diaphragm, adjustment cover gasket, and plunger seal...I don't really know what to call that. It's a cup type seal on the actuator rod that sticks out of the end of the control unit. Pressure tested it to 20 psi, had a very slight leak until I depressed the actuator rod, then it stopped...don't know what to think of that. Installed control, and drove the truck. Seemed to be a bit more responsive, but still drops power in the same throttle range. But now instead of stalling once the revs drop, it will idle. Still doesn't run right after it drops out, lacks power off the line...but it doesn't die like before. As before, I can shut it off, fire it up, and it runs fine again. Still scratching my head on this one, what do you guys think?
 

Truck Shop

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Dec 7, 2015
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WWW.
Talked to a good friend of mine 32 year ex Cat man. He primarily worked 3406/3306 years back.
Ran through all your symptoms. He agrees it's pump related but It defiantly needs expert cat
attention. He said being a 89 with X amount of hrs/miles it truly should be removed and completely
redone/inspected. As far as flyweight pins those can be a issue but the reality is those can and do
break which puts a hole through the side. He brought up the fuel return defuse'r plate on main
housing under the long main housing side cover those can deteriorate and cause issues.

He's a very picky Cat mechanic, worked Spokane, Pendleton and Pasco Cat Shops.
 

Cory W

Active Member
Joined
Nov 13, 2022
Messages
35
Location
Upstate NY
Talked to a good friend of mine 32 year ex Cat man. He primarily worked 3406/3306 years back.
Ran through all your symptoms. He agrees it's pump related but It defiantly needs expert cat
attention. He said being a 89 with X amount of hrs/miles it truly should be removed and completely
redone/inspected. As far as flyweight pins those can be a issue but the reality is those can and do
break which puts a hole through the side. He brought up the fuel return defuse'r plate on main
housing under the long main housing side cover those can deteriorate and cause issues.

He's a very picky Cat mechanic, worked Spokane, Pendleton and Pasco Cat Shops.
Thank you for taking the time to talk with your friend, I appreciate it. Yeah I'm about at the end of what I can do myself, I don't want to attempt any governor work myself. I will have a service manual soon, I may look into removing the pump assembly and taking to someone who knows what they're doing. I'm done hauling for the year, so it'll be on bedrest until spring. Big job in the spring, should be all set by then!
 
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