lost mileage found

[lbrown]

I finally got a fix on my 10% mileage loss. About 1 1/2 or 2 years ago my mileage went from about 20 to about 17 or 18 mpg. I found a bad KSB solenoid sensor and replaced it. Winter intervened so could not tell if that fixed it or not. Then mileage would be seem to be OK and then go to pot. Finally took it into Cummins Rocky Mountain in Billings and had the valves adjusted and was going to have the injector pump timing checked but the mechanic said usually if it is timed properly it should never go out of time. He then decided to remove the aneroid diaphragm (where the star wheel is and where the air control tube hooks up) to check on the pin down there. The pin was stuck/sticky. He got it freed up and I got the 19 mpg on 1 tank of fuel and it appears to be permanent just looking at the fuel gauge drop versus mileage.



Something else to look for if you have similar symptoms.

 

[RDusch]

Lbrown,



Where is the KSB solenoid sensor?? and what was it doing, keeping the silenoid energized or deenergized??



i had the same milage drop a few years ago 20+ to 16, no loss in performance, just a drop in milage, i've replaced transmition, torqueconverter, injection pump, injectors, just about every thing and my milage is still 16, kinda suck if a 20 dollar part corrected the problem, allthough it was a good excuse for a little bombin!



Rick D.

 

[Midnite]

Lbrown, I'm not quite sure what you mean--are you saying that the KSB solenoid caused the milage drop, or was it the sticking pin down below the aneroid diaphram?



By the way--what's a KSB solenoid?



Thanks,

Mike

 

[WestTN]

KSB

Remember that Bosch is german. I don't know the german words, but translated, it means 'cold start valve. ' It is a electrical/mechanical timing advance built into the pump.

 

[Rockcrusher]

KSB

Same question @ KSB. Where is it located?

One thread said its the cold weather start valve in the pump, but where in the pump and how do you get at it?

 

[Jim Curry]

Don't quote me on this, but I believe the KSB selinoid is the one located directly under the fuel pump and the sensor for it is on the top of the manifold above and to the right of the pump.



Jim Curry

 

[lbrown]

Everything is pretty much covered in the previous posts. The KSB solenoid switch is also called the air temperature switch and is on the drivers side of the engine sticking in the intake manifold. There are 2 sensors that look alike, the KSB switch is the back one. The KSB solenoid is the one on the side, about the middle, of the injection pump with a wire attached to it. The KSB is a cold start timing advance. With cold temps the switch is closed and the KSB is energized. When it warms up it should open.



However, replacing the malfunctioning KSB switch did not seem to cure the problem or make much difference.



It was only after the aneroid diaphragm was opened up and the pin that is down the shaft was freed up that the milage came up. The boost pressure is supposed to lower the diaphragm pushing the pin in and releasing the throttle is supposed to pop the pin back out as I understand it. Of course the fuel system diagnosis section in the service manual does not explain any of this. All it says if one has problems with the injection pump, replace the pump. I had a mechanic that saved me about a $1000. 00 because he knew about this pin.



The aneroid diaphragm is I think where the star wheel lives.

 

[BushWakr - RIP]

Here's a basic picture of the pump.. KSB is #2

This is the basic VE44 pump. Actually its off a Volkswagen I think, but the parts are identical except there are 6 injector outlets instead of only 4. Item # 2 is the KSB Solenoid.

 

[BushWakr - RIP]

here's a lame drawing I attempted...

hope this helps a little.

 

[CToney]

How did they free up the sticky pin WD-40?

Could someone do this themselves?

Should guys with higher milage trucks get this checked out?



Just curious



CR Toney

 

[WestTN]

KSB Valvw

Here is a picture of my KSB valve. This is on a 1989. It is right above the power steering reservior cap and right below the accelerator linkage. You can see a small high pressure line exiting the valve and going toward the top and front of the pump.

 

[lbrown]

to CToney

In answer to your questions:



Yes, the mechanic sprayed WD-40 into the hole where the diapragm shaft went, let it sit and then used a pick to make rod/pin move back and forth with the diaphragm removed. After that he put some white grease on the offset cone plunger (see BushWakr's picture - a very good representation).



Could one do it themselves - yes but if you had a mechanic you trusted I would use him. Couple of items I observed



Mechanic marked top of diaphragm so it would go back in same position



The 4 bolt/screws holding top of diaphragm cover were extremely hard to remove. Mechanic mentioned that one can bust things if too much downward pressure used. So he used a big screwdriver, a wrench to add leverage to turn screwdriver and his head to put downward pressure on the screwdriver.



Should older cummins be checked.



I would not if you don't have the drop in mileage. I did have some dirt on the top of the diaphragm (don't know where that came from since it should be pristine in the manifold) so that probably caused the problem. I subscribe to the if it isn't broken, don't fix it.