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Engine Specific Info and Questions => IDI Engine => Topic started by: Spokerider on February 21, 2014, 01:21:52 pm
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I have a KSB solenoid on a 1993 1.9 TD Golf pump. It has a terminal on it for 12v.
Because this AAZ engine / pump is not going back into a vw, what do I do with the KSB? Have a switched 12v wire to it at all times?
Dug up some info on the KSB and 1st gen Cummins;
KSB = 'Kaltstartbeschleuniger' – which is German for “Cold-Start-Device”.
The KSB is the little round component about the size of a tall shot glass mounted on the drivers side of the injection pump. The early KSB and late KSB do NOT swap, nor do they have the same operating function.
The KSB is used as a cold start aid. It will advance the timing on the engine when cold, and is designed to provide substantial injection timing advance in the low engine rpms so as to improve engine operation / emissions when the engine is stone cold after start-up. When in the engine rpms come up, the substantial timing advance tapers off to a much smaller measure of advance. The KSB does not function after the engine coolant reaches ~160* F.
VE44 Non-Intercooled KSB.
Pre '91 engines used the ‘wax motor’ type KSB, called so because a pellet of encapsulated engineering wax/plastic expanded when heated to move a plunger, which internally advanced the timing. 1988 emission requirements required the timing to be advanced when cold, to reduce white smoke. The non-intercooled trucks have a "wax motor" that opens the bypass passage in the KSB unit. When the ignition switch is turned ‘on’ an internal heating element begins to heat up the wax, the expansion of which opens the bypass. It may also have a voltage reducing resistor, but I am not sure. The wax motor style does not open instantly, but relies on an approximate warm-up delay to simulate the time required for the truck to warm up. The KSB is located on the driver's side, low, and toward the front of the VE44 pump.
The earlier 89-91.5 (non-I/C) wax motor type KSB holds the valve open when cold. When the engine is started the valve is already open, increasing timing. As the engine warms the pellets melt and the valve closes. This type requires 12v to close and function correctly. Without 12v power, the KSB will remain on, which can be hard on the pump.
VE44 Intercooled KSB.
The 91.5-93 KSB works in conjunction with a thermistor sensor in the head. When the ignition switch is in the ‘on’ position, 12v power is present at the thermistor. When cold, the thermistor sends 12v power to the KSB solenoid, which opens the KSB. Upon starting the engine, injection pump internal case pressure will advance the timing. 12v switched power is required for the KSB to open and function correctly, and will turn off when the thermistor sensor warms up and opens the 12v circuit, thus removing 12v power to the KSB. If unplugged, the KSB will simply not function, which will only possibly make a difference when cold. Under 90 deg., voltage is applied to the solenoid, blocking the fuel return path, and using internal pump fuel pressure, advances the timing slightly. Over 90 deg., no current is applied to the KSB solenoid, fuel is allowed to return via the normal operating fuel path. The timing advances normally thru internal porting, and sliding plunger. Also, between the switch and the solenoid is a resistor, mounted to a bracket on the side of the head, that reduces the voltage to the solenoid down to ~ 8V (when current is flowing through it & the solenoid -- if you just disconnect the wire at the solenoid you will get battery voltage). The solenoid operated KSB works instantly when you connect & disconnect the voltage to it -- when it is working you can hear the engine speed pick up and drop off connecting & disconnecting it.
Wondering which type vw used?
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The valve you have is probably not actually a KSB, it is most likely on the opposite side of the pump (away from the head). In most cases it is an emissions control device that prevents timing advance to reduce NOx emissions. Depending on the specific pump it may require a constant 12V or need to be disconnected for best performance. Needs experimentation, but won't harm the pump either way.
Disregard if it is on the cylinder head side of the pump, though if it is you probably have a non VW pump.
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My guess is that if they used one, it would be the latter, but a photo of the device in question would be most helpful to identify it, as does that last sentence in the information you posted.
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This is the pump.
You can see the ?KSB? It is below the throttle shock absorber, in the bottom middle of the pic. It has a small steel line with banjo fitting, running from the KSB valve body to the upper / front of the pump housing. The 12v terminal on the KSB is hidden from view because of the shock absorber.
(http://i293.photobucket.com/albums/mm79/Spokerider/BoschVEInjectionPump018_zps428721d1.jpg) (http://s293.photobucket.com/user/Spokerider/media/BoschVEInjectionPump018_zps428721d1.jpg.html)
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That looks like the later solenoid type, in the place where you would expect to find it on an early Cummins too.
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I had a thread about these awhile ago, my oddball Audi NA pump has one, but it is longer and thinner and functions like a cold start device.
That shorter, stubbier one I believe changes timing for emissions reasons as was mentioned. I'd be tempted to do away with it, and add a manual
lever for cold start advance. Or try to.
edit: this is the "wax motor" automatic cold start variety.
http://bricofoy.free.fr/voiture/pompe/dsc05348.jpg
Further info here: http://www.appropedia.org/Bosch_VE
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I just found the thread, http://www.vwdiesel.net/forum/index.php?topic=33075.0 (http://www.vwdiesel.net/forum/index.php?topic=33075.0)
It looks like it is a timing retard device to control emissions. I'm not sure what the difference is between this and the advance, the solenoid itself looks exactly the same, so it must be how they plumbed it. It is definitely NOT a wax-motor thing, those have a more elongated housing to hold the pool of wax obviously.
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I love forums, they combat my crappy memory. :)
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The cold start solenoid bumps the timing up. This one instead allows pressurized fuel to push against the timing piston preventing it from moving. This device basically disables the dynamic advance on the pump when it is open.
You almost certainly just want to feed it +12V when the key is on or you will have poor mileage and performance.
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When i put power to mine, it made a whole lot more power and gave me about 3mpg per tank more :)
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The one like that on my D24 switches off power above 6000 feet to advance timing across the board. Makes the car sound like a bag of rocks if it comes unplugged at sea level.
It also has a spring and shims pressure regulator for when it's 'on', and those shims are spring loaded and easy to lose. 'load sensing advance' I think they call it.
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Thanks for all of the replies.
I will wire it in with the stop solenoid as suggested.
I just finished taking the pump apart to put new seals in. That 'load sensing advance' solenoid is the one piece that I didn't take apart and clean inside. I just re and re'd it with the timing piston cover that it is attached to. Is it one of those gizmos best left alone? at risk if loosing pieces?
I lost 3 E clips from the pump linkage while *trying* to carefully remove or replace them. Those effin things fly faster than my eyes can track once sprung, and once they hit the shop floor, they are gone forever ::).