Hello, all, long time since I visited. Back in the first gen world!

Anyway, I have an early 91 new to me, and when it starts, it idles kinda low for the first couple seconds, then kicks up to a normal sounding idle. I have had a bunch of these engines and never experienced this.

Wondering what the thoughts are on it. Its not a cold weather chug or anything like that, I have started up on colder days with other trucks and not seen this. Doesnt sound bad, but it is unusual.

 

BUMP
Same issue with non ic engine, with no ksb (bus pump)
Tooth skipped, have gone back and forth
raised fuel psi up and down
mail fuel screw in and out
Grid heaters are working
Holley black pump into screw on filter
Took down pipe off for some welding and wet soot on the inside, like black mud
Thought about a sticking injector, bleeding #2 didnt affect idle but did get good fuel squirt
i get black on start up then continues to haze like its cold
will do the same thing every time shut down and start again
Very stumped and frustrated and working long hours, close to selling

 

Timing advance is base off of internal case fuel pressure. Timing advance is used for cold start and idle. It can take a couple seconds before there is enough pressure to advance the timing at idle.

 

The oil in your down pipe is probably your turbo seals. Take the intake an exhaust off the turbo. See how much free play you have on the shaft ends by pinching the nut w/ your fingertips feeling for play.

 

zero play just rebuilt it last year.
Just went out and drove it, grey everywhere and i dont think my neighbors appreciated it.
Will these things start if say you jump it two teeth either way

 

i have the same problem but i only happens if the truck has been sitting for 8+hrs and i start it when its unplugged. I have noticed on mine it varies however from 5 to -20. Right now I am experimenting with different fuel additives, so far diesel kleen is the only stuff that it has happened with. Of course, I also believe I am due for injectors.

 

Problem solved, went with a ppump motor. Same turbo but no oily soot now.. probably washed the inside of that motor like a ****