[Joxxxi]

Fuel Pump - KSB

Can anyone tell me what the part circled off the fuel pump does? It has a wire connection going to it. The engine runs fine without it hooked up.

 

[scout4bta]

That's the KDP valve, used to advance and retard the timing durning cold starts.

 

[Paul(in NY)]

The KSB provides a cold start timing advance to minimize white smoke. Emission requirements in 1988 prompted the need for a cold start timing advance system (KSB) to minimize white smoke. It is not a cold start aid in starting device.

The KSB in the picture is the Wax Motor style. The sensor is located in the engine coolant jacket under the intake manifold and is normally open (NO). When the engine temperature (coolant) reaches 160 degrees F, the sensor closes and applies 12 volts to the KSB wax motor, which returns timing to normal.. Once the engine reaches 160 degrees, the KSB is no longer functional.

To disable the KSB, just run a constant source of 12 volts to the KSB and it will not function. Disable in this manner totally by-passes the coolant sensor. All my trucks run with the KSB in a Non Functional Mode ie 12 volts constantly on the KSB Wax Motor, the same as it would be after warm up. I dont have any white smoke issues

There is another type of KSB powered by a Solenoid. Its sensor is in the Intake manifold cover and measures air temperature in the intake manifold. The sensor operates at 90 degrees F and is Normally Closed (NC). When the intake internal air temperature reaches 90 degree F, the sensor opens and timing returns to normal. To disable this type of KSB, Just unplug the wire to the Solenoid and you will no longer have cold start advance.

Paul

 

[66gaza]

Paul, do the A & P pumps have something similar? If they do it must be internal as I have never seen anything stuck on the side of an inline pump.

Gaza

 

[Paul(in NY)]

Paul, do the A & P pumps have something similar? If they do it must be internal as I have never seen anything stuck on the side of an inline pump.

Gaza

Gaza, I dont know. My Cummins shop manual only shows them on the Bosch VE pumps on 4B and 6B engines.

Paul

 

[Lustalbert]

Any idea how much it will advance/retard the timing?
Or how fast it is to respond and change the timing?
Just thinking it could be an interesting way to bump the timing a little every now and then for a little extra umph, but not have the pump timed at that advance all the time.

 

[Joxxxi]

Paul,

Thanks for the information on this. We've been scratching our heads trying to figure it out.

 

[Paul(in NY)]

Any idea how much it will advance/retard the timing?
Or how fast it is to respond and change the timing?
Just thinking it could be an interesting way to bump the timing a little every now and then for a little extra umph, but not have the pump timed at that advance all the time.

My Bosch Pump Manual " Diesel Distributor Fuel-Injection Pumps", Page 24, talking about the KSB.

First, there is a manual cable operated KSB. When the cable is pulled, the Timing advance is approx 2.5 degrees. Then the Bosch Manual refers to the Automatic Mounted KSB ( such as we use). They say that the advance depends on the engine temperature and also ambient temperature. The timing change appears to be immediate from what is discussed in the manual. Thats all that is written in the Automatic Mounted KSB on advance.

However, if the Cable pull KSB advances to 2.5 degrees, the automatic must be in that ball park to eliminate white smoke.

I have never run my trucks in a comparison with the KSB deactivated vs on all the time. I believe your thoughts are worthy and need to be looked at. I am out of time for such tests prior to winter. Maybe someone else can run some comparison tests and post back.

Paul

 

[Paul(in NY)]

Any idea how much it will advance/retard the timing?
Or how fast it is to respond and change the timing?
Just thinking it could be an interesting way to bump the timing a little every now and then for a little extra umph, but not have the pump timed at that advance all the time.

Just for clarification. The KSB does NOT retard timing. It either advances the timming or allows the timing to return to its normal setting.

Paul