I don't think it is the KSB (kaltstartbeschleuniger -- cold start help/aid). The KSB gets an electrical feed from the second terminal on the fuel shut of solenoid via a temperature sensor in the intake manifold. When it is activated, it raises the pressure in the chamber that controls the injection timing, advancing the timing by about 5 degrees. If the air in the intake manifold is over about 50 degrees, the KSB doesn't come on anyway. The truck should start without the KSB down to freezing without any real trouble, though it will run a little more roughly, and smoke blueish smoke.<br><br>It is possible that the KSB gets its feed via the solenoid so that it runs at 10 volts or so instead of the full system 13.6 Volts -- I can't confirm that they are using the voltage drop on the solenoid, or if they just thought it was simpler wiring.<br><br>My best guess at this point would be that the timing mechanism in the pump is sticking/not working properly and/or the pump timing was set wrong when the pump was rebuilt.<br><br>If you had bad injectors, it would knock and be more consistent. It is remotely possible that it is some sort of strange fuel leak.<br><br>Good luck.

 

apache,

The fuel solenoid has two wires on it, one is the trigger voltage (12v) for initial startup and the other is a maintainence voltage (10v) to hold the solenoid open during running condition.
The KSB is a temperature activated valve which closes the fuel return off and raises the internal pump pressure from 4 bar(normal running pressure) to 8 bar (cold start pressure).
The KSB results in the same thing as actually physically advancing the timing on the pump, just uses pressure increase to achieve it.
There have been two different types used. One was a kinda of wax filled unit and ran at 10v and the newer is a 12v non-wax item. The original 1st Gens from 89-91.5?? used the wax type.
Either way, the KSB would not cause &quot;failure to start&quot; condition.
It WILL cause a poorer idle, more smoke at cold start conditon.
Once intake air temps reach approx 90*F the KSB goes back to sleep and waits for the next cold start condition.

Hope that helps some...

Bob.

 

Mr. Bushy, it sounds like you have a good grip on this. If the internal pump pressure is a function of RPM, does the Klinken der Messerschmidt valve bypass the pump pressure valve so it will move the roller ring piston? (I have an old Diesel Rabbit pump that I made a cutaway out of long time ago). Thanks, Jim ???

 

Ok, here we go..... ;D ;D
In order to be as accurate as possible I'll take much of the manual info verbatum here.....
&gt; There are two methods of KSB advance, one is mechanical using what is called a Bowden Cable and the other is via an &quot;automatic&quot; system which uses a temperature/sensor control to alter the amount of KSB Advance based on real time requirements resulting from temp changes.
The automatic control of pump interior pressure is modified through a bypass in the pressure-holding valve.
The method of operation is:
The fuel delivered by the fuel-supply pump (return fuel is shut off sending it back) is applied to one of the timing device piston's end faces, via the injection pump's interior. In relation to/with the injections pump's interior pressure, the piston is shifted against the force of its spring and changes the start-of-injection pressure along with increasing pump speed and the resulting rise in pump delivery.
There is a restriction passage in the pressure-control valve's plunger in order to achieve the pressure increase needed for KSB function, and the resulting advance curve. This ensures that the same pressure is effective at the spring side of the pressure-control valve. The KSB ball-type valve has a correspondingly higher pressure level and is used in conjunction with the thermo-element both for switching-on and switching-off the KSB function, as well as for safety switchoff. Using an adjusting screw in the integrated KSB control valve, the KSB function can be set to a given engine speed. The fuel supply-pump pressure shifts the KSB control valve's plunger against the force of a spring. A damping restriction is used to reduce the pressure fluctuations at teh control plunger. The KSB pressure characteristic is controlled by it's plunger's control edge and the section at the valve holder. The KSB is adapted by correct selection of the KSB control valve's spring rate and its control section. When the warm engine is started, the expansion element has already opened the ball valve due to the prevailing tmeperature.
I'm not too clear on this particular aspect but I have heard that the advance will range from 2.5*camshaft to approx 5*camshaft angle based on engine temperature or ambient temps.

Sooooo, basically the increase in fuel pressure results in a shift of the timing device piston and the sliding block-and-pin which, engages in the roller ring. The roller ring is rotated by movement of the pin, and the relative position of the roller ring-to-the cam plate, changes, with the result that the rollers lift the rotating cam plate at an earlier moment in time. Basically the roller ring has been rotated through a defined angle with respect to the cam plate and the distributor plunger.
The manual shows the maximum angle is 12* camshaft (24* crankshaft.)

You had to ask didn't you.... ;D
Now I got a headache too....
Bob

 

Thank you, Bushy! I was trying to compare the pump roller plate with a distributor cam, where the weights were pulled out mechanically for starting, then returned to normal operation after the engine fired. Now I understand. I agree, you can take out the KSB and throw it away, I don't believe it is causing a no start problem either. This is a good one, Apache, I hope you get 'er repaired. What ever happens, the results will be informative!! Jim. (and hopefully with little expense to you :'()

 

As Red Green would say....&quot; remember we're all pullin for ya, we're in this together, if the women don't find ya handsome, they should at least find ya handy...&quot; <br><br><br>Bob, just north of possum lodge...

 

Humm. Now I know why I've never seen any road kills north of the border.

 

[quote author=Bushy link=board=9;threadid=14658;start=15#140802 date=1053569580]<br>As Red Green would say....&quot; remember we're all pullin for ya, we're in this together, if the women don't find ya handsome, they should at least find ya handy...&quot; <br><br><br>Bob, just north of possum lodge...<br>[/quote]<br>Keep your stick on the ice.....

 

My pump rebuilder seems to think its not the pump, but a intercooler problem possibly, blockage or otherwise, I dont see this as possible,nor do I want to pay to the have the truck torn apart as they would at a Tijuana border crossing in search of illegal goods. The two years I have owned the truck in the AM start I always wait for the wait to start light to go out. However it alwasys comes on when the key is turned on even when hot, just for a moment. I see this as a computer precheck of the systems of sorts. If one was to attempt to start when the computer is still in check mode could this cause a shut down of sorts?? Are 93s computer controled??? I have attempted to start after a no start ,by turning the key on and letting the light go out and it still wouldent work . it has not been a problem for several days????. Thanks.

 

Dave is correct, the TC drainback is common. Later models had/have a checkvalve in the line to prevent that but it also hinders oil flow to some degree.<br><br>The 'wait to start' light does in fact test cycle. It comes on and goes out after a few seconds.<br>Is there any way to run that pump back and have replacement put on??? You do seem to have gone thru the more common causes of failure to start.....<br><br>BTW, have you tried to run your fault codes to see if anything shows up there..???<br>Turn the ign. key in this sequence... on/off, on/off, on........all within about 5 seconds..<br>What the far left instrument cluster.... you'll have a series of flashes eg: 4flashes pause 3flashes....long pause.... 2flashes pause 3flashes.... when all the codes are done you will get 5/5 flashes which indicates &quot;end of codes&quot;.<br><br>Bob.

 

Thanks again for the time you take to answer my questions, well if I insisted the rebuilder might go for that,but he is so inclined to find a problem elsewhere I dont know. I suppose I could sick my x-wife on him, then surely he`d give in. I ran the codes as suggested and heres what I unfortunatly saw, 5 flashes a pause and five more flashes, all at the slow rate well say. Kinda hoped id see something, if this is like the old ferd, it stored the codes and kept them until you disconected the battery for a couple minutes, oh well keep trying. for now its not acting up so ill continue until it starts in and try the code retrival again.

 

55= end of codes, so you have no problem codes <br><br>Attempting to start durring the &quot;wait to start&quot; cycle will cause no harm. The PCM cancels the cycle when you do this.<br><br>

 

This may be grasping at straws but when this happens again try removing the fuel tank filler cap. See if your getting a vacuum condition in the fuel tank.

 

Does any one know the end to this story. This almost exactly what my truck is doing.
Grant

 

Well after a couple of weeks it just stopped and it has been 1 year or more and 30k miles or so. shortly after it cured itself It would occasionally just momentarly crap out when I hit the go pedal, almost like it someone shut the key off? Now its just fine. I never did really find the problem, but I suspect a air leak in the fuel lines or? I replaced the lift pump as well shortly after and wonder if the snap on line to the Injector pump was suckin air. Try checkin the connections to the fuel shut off and KSB dealy also they seem to come loose easy.