82F100SWB

Well, I finally got the 'ol 92 back to driver status, 2 weeks of daily driver useage so far and nothing has exploded or fallen off, so I think it fared it's 3 years of doing nothing fairly well other than getting uglier and rustier... LOL
Anyhow, I'm out to solve a timing issue this truck has had since I bought it, when it was 100% bone stock as far as I know.
Starts great, runs great, but when it is cold under low load, midrange rpm, say crawling away in first gear, fairly light pedal, starting at around 1500 rpm, it will stumble and pour blue, this goes away when it is up to temp, but, no load it will pop and miss and smoke blue/white in the mid rpm range, once it gets past it it clears up and is ok. A quick blip of the foot feed on a downshift will produce a pop out the exhaust and a puff of blue/white.
Under load/boost, it runs fine.
On light decel with fuel still applied to the point it is more or less coasting, you can hear a definite change in how it runs, more or less throttle gets it back to the normal Cummins rattle.
On a cold start, when ksb shuts off there is a significant increase in, for lack of a better word, diesel rattle.

I have always just driven around it and figured it would be cured when I got around to bumping the timing, but, talking with a good friend of mine who is a Cat engine specialist he thought it almost sounded like too much, but couldn't be certain without driving it.
Any input would be appreciated.

j_martin

KSB should advance the timing, and let it return to normal when it shuts off. It almost sounds like you have 1992 KSB wiring on a pump with a 1990 KSB in it.

Could be the injectors are 50000 miles or so past end of life.

Does the engine consume lube oil?

82F100SWB

Negative on the oil useage, 1-1.5l in 6000 mi, and it always has 0w40 in it so that is useage by the external lubrication system, not consumption.
I'll have to look at the pump today, I believe I ran the numbers in the past and it is the stocker. And I'm pretty sure the ksb on my 89 was visually different.
When I got the truck the ksb did not function, the temp switch was dead. It was replaced with a Cummins part for the proper cpl.
Injectors are a possibility but it has a rather low 162k miles indicated.

ClassA4x4

It sounds like you have too much timing to start with, at idle. In this situation the KSB further advances an already advanced timing causing the injectors to start injecting fuel at the end of the compression stroke, rather than at the beginning of the power stroke. That's the smoke you're seeing. Under load, timing is retarded, the IP responds with more fuel, rpm goes up and catches up with the advanced timing, i.e. fuel is now injected past the compression stroke at higher rpms.

I noticed this when I installed my m&h timing advance spacer which advances the timing at idle despite of the claim that it doesn't. If the ksb is on, the idle retards, rattle muted by unburned fuel; when off, the idle rises, rattle is pronounced.

82F100SWB

Ksb is for sure standard 92 stuff. I need to get in there with some brake clean but if anything the timing is a hair below the marks being lined up.
I'm starting to think I should open it up and check the gear set timing if I do indeed have to much timing. Sounds like it has been advanced a bit much.

j_martin

The only way you can check the timing for sure is with a dial indicator installed in the 12mm plug hole in the back of the pump, in the middle of injector lines. It's in the book.

82F100SWB

It for sure was not enough, gave it a 1/8" bump and it was much happier, but still could use a bit more.
I may jump the gear a tooth when I fix it, the kdp; which was supposedly fixed for the previous owner, has bit me...

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