BlueOxD350

I haven't seen the answer in any of the past threads, so I have to ask... how much holding pressure should the ksb solenoid have?

Here's the situation: I'm still chasing down a running-rough problem, smoking and sputtering... I'm thinking timing, but have yet to adjust it. I took the truck (hauling 10k tractor / trailer) from CO to MI and back last week, and warmer / lower elevations really helped the old girl out...
Regardless, it runs MUCH worse when it's cold. I have a full 12v coming down the line from the intake temp sensor to the KSB. I pulled the KSB solenoid, and applied power to it, and the plunger extends about 3/16". I put the solenoid back in, and cracked the line coming out of the top of the KSB valve... and when I put power to it (with the engine running, of course) I get two light spurts of fuel, and then nothing. I hear no difference in the way the engine runs when all is hooked up, and I apply power to the KSB. Thoughts?

wannadiesel

Sounds like the solenoid is working. Have you pulled the check valve out of the other end of the housing and cleaned it up? There's a check ball in there that can stick and cause problems.

BlueOxD350

Reckon I'll pull it apart just as soon as this 20below cold front passes... anything special I should be careful of in disassembly, or just catch the checkball before it falls into the snow and clean everything up???

Thanks wanna ... your expertise is MUCH appreciated! Although I've had my Cummins for eight years now, I've had to do SO little to it, that when something does go wrong, it's all new territory... and new territory in the frigid cold is not my idea of a good time......

wannadiesel

The check ball is internal to the valve. Nothing should fall out except fuel.

BlueOxD350

So I pulled the other side of the KSB apart yesterday, and the checkball moves freely with adequate spring pressure behind it. So now I'm stumped... I pull the solenoid out of the one side, and when I apply 12v it clicks out 1/8" or so .... the other side of the KSB holds this check valve, and the ball depresses smoothly. Seems like everything should be working right in there... but 12v to the solenoid makes no change in how the engine runs, and it still smokes like the dickens runnin cold, sputterin all the while. I need that timing bump.
Here's my question then: what's in the middle of the KSB? Solenoid on one side, check valve on the other ... but one doesn't appear to directly press on the other... Is it just fuel pressure that pops that ball in to allow fuel flow? I.E. the solenoid on the one side will just seal off the return flow, and the pressure building up will depress that ball, sending extra pressure up the fuel line into the injector pump? I'm still just not getting fuel to flow up that line...

Could my solenoid just not have enough holding pressure? Any way to test? I'm thinking of pulling the solenoid, starting the truck (I know, fuel EVERYWHERE!) and then plugging the hole that should seal when the solenoid kicks in - and see what happens... thoughts?

Tuckerdee

My understanding is that fuel doesn't "flow" through this line. It just supplies pressure to the timing mechanism so that the cammed/ramped disk will rotate slightly and retard the timing. But I could be wrong.

bgilbert

How about calling it a diesel and be done with it? IE, mechanical injection diesel engine that smokes when cold.....

JDGnut

When you are checking the voltage to the KSB.. is the KSB hooked up?? If not check the voltage to the KSB with it hooked up.. If you have resistance in the wires to the KSB, it will not show up unless you have a load on the circuit...

BlueOxD350

How about not wasting our time with "just-deal-with-it" remarks ... if it isn't right, it's worth the time to fix it. There's a reason I'm coming on a half-million miles, and it's not because I ignore problems just because they may be difficult to diagnose or research.
Besides that, smoke wouldn't be a problem ... a county-wide fog is. Not to mention the sputtering and popping under any throttle until temps are way up...


Tuckerdee - thanks, I'll check for pressure instead of cracking the line and watching for fuel.
JDG - when I apply voltage to the solenoid, it clicks. But I will double-check that there is adequate voltage when the circuit is hooked up and complete.