1st Generation smoking at startup

[Puffin Smoke]

I have a buddy that has a 92 Cummins 2wd Auto that blows blue smoke when he starts it and it sounds like its skipping cylinders. Said he just got back from a 4,000 mile trip Alaska to Washington and back and he had no problems nor a power loss. Said it started when he plugged it in the other morning. I asked him if it did it when it was warmed up and he said he wasnt sure and that he would let me know tommorow. Its got like 190,000 miles on it. I thought maybe cause it was cold and the switch from #2 to #1 diesel fuel. Anybody have this problem or maybe give me some ideas on what it could be so I could relay it to him?



Thanks

Mike

 

[formula]

Sounds like if it happens when it's plugged in it could be the KSB.



digging for my previous post... ... hummm... ... here it is. .



"..... The intermittent idle smoke is most likely caused by the KSB which advances the timing at idle, by way of increasing the internal pump pressure, depending on the intake air temp. So, if you run the truck down the highway and then stop and check idle smoke it'll probably be very little. This is because the cool air coming from the intercooler has cooled off the intake manifold and the KSB temp switch which will turn on the KSB and advance idle timing. If the truck sits with the engine off for a few minutes, the heat from the engine will warm up the intake manifold and the KSB temp switch, turning off the KSB and retarding the idle timing and making more smoke. You can check this by idling the engine when it's all warmed up, if it smokes, jumper the KSB solenoid to the battery +terminal and see if the smoke is reduced. You should also hear a change in engine sound and a slight increase in rpm. Also, if it's idling with no smoke, try unplugging the KSB wire and watch for the opposite effect. "



How long has he been living in Alaska for? Has he had this problem in winters past? If the ambient temp here goes below 20F or so and my engine is stone cold, it engine runs rough as hell and smokes like crazy for a bit till it starts to warm up. It may be time for some fuel conditioner too.



Sean

 

[Puffin Smoke]

He hasnt had the truck that long. Couple of months. Is this KSB swithc replaceable and how much?

 

[BushWakr - RIP]

He could also have a malfunctioning KSB temps sensor. It is more likely to go out than the KSB, although it can go too.

Also, skipping cylinders sound is alot like bad fuel, plugged fuel filter (has he drained off any water in the filter?). Run some good fuel conditioner thru the truck double up on the dosage.

The ksb can be seen here:



https://www.turbodieselregister.com/user_gallery/displayimage.php?&photoid=2499&width=2



Look thru the other pics in my gallery for more pump pics.



Bob.

 

[formula]

The KSB temp switch (~$50 from stealer) and wiring harness (~$16 from cummins) are replaceable. The solenoid probably is too, but highly unlikely that there is any problem with it. The situation you describe actually sounds quite normal for cold weather and for the KSB. But, just how much smoke are we talking about, and for how long does it smoke after it's started? Don't forget the fuel contitioner.



Sean



edit- I agree with BushWakr on the bad fuel / filter / water scenario. Good idea to check and change filter anyway for cheap insurance. But the "skipping cylinders"... . does this happen only when it's cold or does it sputter and shake when it's all warmed up too?

 

[AlK]

Puffin Smoke,

Also check that the electrical connection on the KSB is tight.

 

[bflood]

I had the same problem when I first got my rig. It got worse as the ambient temperature got colder. Turned out to be a bad connection on the KSB solenoid . . . that simple. The connections can loosen up from engine vibration.



I would suggest checking this first. Put a voltmeter or test light on it and start engine (when cold). You can also jumper it to force the KSB and listen for a slight but noticeable change in engine sound and rpm at idle.



Hope this is it for you.

Bruce