bad miss and smoke cold start

[c-moor29]

Just bought a 92 w350 chassis cab with 200k on it, It starts rite away but miss's and blows white smoke for about 5-10 min no load, less time with more load, has a close to new Injection pump and the previous owner say it always started like that (he owned it for about 8 months, the original owner had the injection pump replaced before owner 2 bought it). I kinda sounds like air in the lines but that shouldn't take 10 min to go away? It uses no oil, next to no blow by, and runs fine warm, although it has next to no diesel clatter. any chance they got the gear off a tooth when they did the pump? any other ideas,

 

[NIsaacs]

The 1st Gen's. used a KSB solenoid on the injector pump, wire connected to an Intake Manifold Temp sensor. The sensor is probably bad. When the engine is cold the KSB will advance the injector pump timing and eliminate the miss and smoke when cold. When the engine warms up the KSB solenoid will revert the timing back to normal.



Nick

 

[c-moor29]

yeah that could be, but I'm talking cold as being 70 deg weather truck not having been run for a day. and i'm not sure the cold advance would have that much effect in warm weather, but its something to look at
Thanks

 

[NIsaacs]

If the truck has not been run, as in overnight the engine is considered cold and the KSB will kick on. On first start up of the day (any temp) they will run bad without it.



Nick

 

[JLEONARD]

If it happens only when it's not been run for a day then I would first suspect air in the fuel system. Sometimes air can be a tough one to find.

And don't overlook the lift pump. I had one year old one go south... one of the rubber check valves inside disintigrated. It gave me fits until it disintigrated enough to fail completely. #@$%!

 

[c-moor29]

do i just need to jumper power to the ksb solenoid to activate it

 

[Greenleaf]

Not the KSB. That is simply an add on for automotive/emissions. I have not had an active KSB in years and years and I have no such issue.



This particular unit is powered when the sensor detects a cold cyl head. There is no power when warmed up.



As Jay said, you have fuel system issues. Most likely; a small fuel leak at the injection pump (air) ,bad injectors, timing really off (retarded) or fuel drain-back fuel not held in the supply pump and/or inj. (pump more air)



Any above problems will cause it to start hard and/or run rough for a little while.



The KSB solenoid only slightly advances the pump timing (when engine is cold)

 

[NIsaacs]

The OP indicated the engine starts right away. Usually with an air in fuel issue, they start hard. I have found that with the 91. 5/93 models the factory timing is retarded enough that the KSB does make a big difference with a cold start, especially with high milage injectors. I would jump wire it on a cold start and at least see if it helps. If it doesn't then look elsewhere. If the injectors are original they are probably due for some TLC.



Nick

 

[c-moor29]

thanks for all the input, got a chance to look at it today, found that the ksb was not working, and hot wire did help allot, so i pulled the pump and front cover, sure enough they moved the gear when replacing the pump, it was 1 tooth retarded (Lining the keyway up with the mark on the front of the pump, locking it down and with 0-00's lined up had to move the gear a tooth advanced to get it to line up with the pump) put it back together and runs 110% better, no smoke. with no ksb at 50 deg cold engine. next up nv4500 swap, maybe next weekend.

 

[Mel Fuelling]

This winter I had similar starting symptoms when the wire providing power to the ecm corroded through. My first symptom was a fluttering message center while the grid heaters were energized, and finally no charging as the ecm power supply wire corroded.