caterpillar 3406B low boost/power issue

Two thijngs, whern you put the new boots and clamps on torque the clamps to 90 inch LBS. Anthting less the clamp will leak and anything more will cause the clamp to break prematurely. The other question I have is how do you know the ATAAC is not leaking. I used to pressureize them to a minimum of 30 PSI and look and listen for oleaks and then see if the system leaked down without leaking at the clamps. To check the AFR ratio, without disassembling it you can take the line and fitting off and see if there is oil onside. If so the AFR Ratio diaphragm is blown and will cause your symptoms. This can be replaced with little effort if you know what you are doing, otherwise have a "CAT" man remove, replace diaphragm and reinstall the AFR. They cannot be repaired on the engine. One other problem, maybe the timing advance is slipping internally causing the timing to not advance properly. This should be chacked by someone who knows to to check, repair and retime the engine.

 

Fuel line maybe collapsed coming from tank reverse line from tank to injector pump

 

Having lots of black smoke and high idle is usually a good indicator that you have a leak. Replace the boots you have coming and time the motor. Then see where your at, it could be a bunch of things but timing the motor costs nothing but your personal time and is a good starting point. Let us know how you make out.

 

I'd say this guy got it figured out years ago...

 

You want to check the CAC you pressurize it to 35 lbs, start by putting the plug in the right side and pressurizing the system, check the intake manifold, the boots, also the boost guage, and the AFC cover. Plug it at the left side and test the CAC put in 35 lbs air in the right side and read it on the left side.
You want a ball valve to shut the air off and time it for 15 seconds, it should not lose 4 lbs air or you need a new one.
The AFC you disconnect it from the intake manifold and AFC put on an adapter, #4 hose, and 10 lbs air if it leaks the diaphragm is junk.
The fuel preasure you need about 30 lbs at full load and be sure the return line is open.
The timing advance you should get a surge after starting about 2 seconds later it should change. If not you need to get it repaired. I set the timing 1/2 hole advanced, if you have never done it get it set and ask if you can watch.
The timing it should have a slight rattle to it.
JUst a thought!

 

Haha your probably right. I didn't even see the date. My bad.

 

whats the AFC ?

 

Air fuel control/ limits fuel rack travel til it starts to have manifold pressure. Sometimes called smoke limiter or aneroid.

 

10-4 thanks