edwinsmith

I checked my KSB solenoid today. I disconnected the plug and there was no change in the idle. I cleaned and tightened the connector on the wire and the solenoid and I measured 12V on the wire wether it is connected or not. I measure resistance in the solenoid so it isn't open.

I ran the truck until it is up to operating temp. and checked the voltage on the terminal again and it is still 12V.

How do you get the solenoid out? I can't get a socket on it and I'm afraid a cresent wrench will just round it off.

The truck runs fine when it's warm but misses and blows white smoke when it's cold and I start it without the block heater on.

The parts guy at Autozone was clueless since his computer says nothing about KSB solenoid. He said it was the mixture solenoid and he didn't have one anyway.

Edwin

Tuckerdee

I don't really know how the KSB works. But it sounds like you're getting TO MUCH fuel when it's cold. Sort of the equivelent of flooded in a gasser. I can check my wiring diagram when I get home. Maybe the temp sensor that completes the circuit is bad and is always on?

One of the maxim's that I've tried to follow - "Don't go to Autozone for parts that matter." At least in this part of the world, I just get blank looks from the counter person most of the time when I try and tell them what part I need. Do you have a local cummins dealer? or maybe Napa?

G1625S

Edwin,
I too would be curious to see the wiring diagram---my buddy has the snap-on version of alldata at his shop--I think it's called shop key. I'll try to check it out today or tomorrow. The coolant sensor in the head on my truck only has one wire, so I'm assuming when water temp hits 160, it opens the switch to the ksb, cutting the 12 volts. Weather this is true or not, it sounds like your solenoid is sticking and needs to either be cleaned or replaced. I prolly woulda just grabbed it with vice grips by now, but I understand looking for a more proper solution. Maybe a flare nut/line wrench?


Tuckerdee,
how do you like the air bags?

greg

edwinsmith

What size flare nut wrench? I assume it's a metric size and I have very limited metric tools. It's hadt to reach to get a calipers on and there is black paint on it too. I assume it's the one on the drivers side of the pump and has a little 1/8" line running to the front of the pump. If I pull the only other wire I see off it kills the motor so I assume that's the fuel solenoid.

The white smoke is from unburned fuel when it misses when it's cold. It goes away after it warms up a bit. Today it's in the low 60's so the air heater came on but it started and ran right off the bat. Maybe it's not cold enough to activate the KSB.

The white smoke leads me to think I have a worn injector which is popping off to soon and not atomizing the fuel properly to burn when it's cold hence the miss. That's why I was asking about the advisability of removing and cleaning the injectors but so far nobody has answered.

Thanks

Edwin

edwinsmith

Also, According to my wiring diagram, there is NO switch. There is only a thermistor in the air to tell the Air Heater controller to activate the heaters. I assume it also controlls the KSB on the 89. I think the 89 is different from everything else.

The power to the KSB solenoid comes from the Air Heater Controller.

Edwin

G1625S

This is a quote from wannadiesel back when I was inquiring about the ksb system. The switch in the head he refers to is all the way in the back of the head with a resistor in line on my truck. It's a purple wire, I was just out there looking two minutes ago, but I'll have to tear into the harness to find out more.
greg


''I did some more poking around in my Cummins book, the '89 and '90 trucks are supposed to have a wax motor KSB solenoid (like a thermostat). Temp switch for that is in the water jacket of the head. The switch sticks out of the side of the head, just to the rear of the fuel filter. It opens at 160 degrees. There is a 3 ohm resistor in line on some applications, on others the wiring harness is made of resistance wire. There should be less than 10 ohms of resistance in the harness. The wax motor reacts much slower than the electromagnetic solenoid used on the '91 and up. If you pull the wax motor out to test it, Cummins says it must move within one minute. So wait for a minute or two before and after unplugging the solenoid when trying to diagnose the old trucks''

edwinsmith

I am assuming that you're talking about a switch that makes contact when it is below 160 degrees and is connecting 12V to the KSB when it makes and opens above 160. My wiring diagram shows NO SUCH SWITCH.

The KSB is called the Cold Start Advance and wires to the Air Heater Controller. There is only one thermistor to control the AIR Heater Controller and it's behind the fuel pump and wires only to the AHC.

The sensor at the back end of the head is for the temp gauge and has nothing to do with the KSB system since it only wires to the gauge.

Thanks

Edwin

Den

Look in your wiring section and see if you can find the "air heater controller"

Looks like the sensor is not inline with the KSB wire on the 89-91 models. Appears to have a seperate controller (not the engine controller) for the intake warmers, KSB, etc.
The sensor wires direct to air heater controller. Then it controls the KSB on/off with a wire from AHC to the KSB.

Den

edwinsmith

Yes! That's what I have.

Now I'm trying to find a wrench to get the darn thing out to see if it's frozen. It ohms out and I have 12V on the lead wire to it but it runs rough when it's cold.

Thanks

Edwin

G1625S

It'll be interesting to get to the bottom of this. I started to physically trace my ksb lead this afternoon and plan to finish tomorrow. It's not even hooked up, but I want to know exactly what feeds that little bugger!!

G1625S

hehe, guess you fellas got it figured.

edwinsmith

I can trace wires just fine but when they disappear in those little metal boxes is where I get lost. And I DESIGN those things!

Edwin

G1625S

Edwin,
I just looked at the solenoid itself...that is a bugger to get a wrench on I've got my tools stored at a buddies right now, but I'll grab my bigger metric stuff tomorrow an see if I can get a size, if you don't find it by then.
greg

edwinsmith

Thanks. I may need to drop the PS pump out to get a wrench on it. Hopefully it's just stuck with gunk and I can fix it. If not I'll have to find a replacement. This thing is nickle and diming me to death!

Edwin

wannadiesel

Make sure the line and the check valve aren't gunked up. I think instructions are in the thread that's linked to a few posts up. If you jump it to 12 volts, make sure you wait a couple minutes, the "solenoid" is a wax pellet (like in a thermostat) with a heater element, so it doesn't react instantly. I'd expect a truck with the wax motor KSB to run a little pukey for a couple minutes even with the system working right. As long as everything clears out after a minute or two the KSB is doing its job.