Engine smokes & low power...

[jkoehler]

I recently purchased a '99 3500 4x4 w 5/spd; SLT; 126,000 miles. Its also our - me n the missus - first p-u truck and diesel. We really do like it.



Overnight temps get to 32 degrees or lower and I start the truck having waited for the "wait to start light" twice on colder days. Now, when I start the engine for the first time for the day, it'll start w/o smoking. But in 2-3 min it starts to blow blue smoke. This condition will last for several minutes or until (I'm guessing) the engine finally reaches running temps and typical driving RPMs. Also associated with this blue smoke is what I'll characterize as low engine power output - it's as if the turbo isn't working - or in a gasoline engine its not running on all cylinders. Now as soon as this low/restricted power output seems to correct itself, the engines seems to respond to throttle/power commands properly and no blue smoke.



Any similar problems & what was solution? Thanks for the help...

 

[Newf Limo]

J. I'm just wondering, you say it sounds like it isn't running on all cylinders and self corrects and goes to normal RPM's? Does all this happen while it is just sitting there after first start? Or, is this something that is correcting itself under way? The reason I ask is, the 98. 5 cummins and newer, all have software installed in there ECM that allows the engine to go to a higher idle when the temp is below 32 degrees and engine temp is below 140 degrees. If the Outside air Temp (OAT) is below 15 degrees, engine temp <140degrees and a few other criteria are met the ECM will shut down 3 cylinders (fuel starve) so the other three will have to work harder to get the three dead cylinders through their compression stroke. This will cause the engine to run and sound like an old John Deere Tractor . This software is something the previous owner would have to have "Enabled" by the dealer with a DRB III device. There should be a sticker in front of the radiator that says something to the effect of Flash # ---------------. Or something to that effect. What is interesting, and casts some doubt on this theory is, there aren't too many dealers that know that this exists! I also wonder if maybe your Grid Heater isn't coming on??? After you start the truck and it settles down, can you hear the engine sound drop (like it is under a slight load) for 4 or five seconds then return to normal for a few seconds (and on and on and on. . . ) The grid heater preheats the air coming into the Intake (it is also why we don't have glowplugs) but it draws alot of current. This would be noticeable in the engine sound (and possible slight dimming of the headlights) when it cycles. If it isn't working, then your truck is trying to run and warm up on some very cold air, (made colder by any turbo activity, I understand, though at idle there isn't much. ) For information on the ECM high Idle and three Cylinder Idle there is an existing thread under 24 Valve Engine and Drivetrain. Keep thumbing through the pages, you will find it. I would also have a Cummins Mechanic take a look. Just my 2Cents worth!

 

[LSMITH]

Newf has some very good points, but it sounds to me like it needs the valves adjusted, and it is free to do. Low compression usually manifests itself just as you describe and the usual suspect is a valve adjustment. The 12V crowd is a lot more used to this than the 24V. I would adjust the valves and try that, an hour and a half of your time and zero dollars spent. If that does not take care of it then you can continue to troubleshoot.

 

[MCummings]

Originally posted by jkoehler

I recently purchased a '99 3500 4x4 w 5/spd; SLT; 126,000 miles. Its also our - me n the missus - first p-u truck and diesel. We really do like it.



Overnight temps get to 32 degrees or lower and I start the truck having waited for the "wait to start light" twice on colder days. Now, when I start the engine for the first time for the day, it'll start w/o smoking. But in 2-3 min it starts to blow blue smoke. This condition will last for several minutes or until (I'm guessing) the engine finally reaches running temps and typical driving RPMs. Also associated with this blue smoke is what I'll characterize as low engine power output - it's as if the turbo isn't working - or in a gasoline engine its not running on all cylinders. Now as soon as this low/restricted power output seems to correct itself, the engines seems to respond to throttle/power commands properly and no blue smoke.



Any similar problems & what was solution? Thanks for the help...

Do you have an EGT gauge??



What this seems like is the grid heaters work at first, and then turn off in 2-3 minutes and the Exhaust Gas tempatures start to drop causing the smoke. If my EGT gets below about 200* or I don't wait for my grid heaters my truck smokes blue and gray until the idle EGT gets above 350*.



if your EGT is below 200* your truck is most likely gonna smoke.

At idle, your turbo is producing 0 PSI, even cruising at 45MPH (no load) the turbo is still only producing no more than 4-5 PSI



If there are any other problems that could make this phenomena happen, I am not familiar with them, and I will have to let other TDR Members help you out.



MerrickNJr

 

[Jvann]

low power and bluish white smoke

This certainly ain't what you want to hear but all I can do is tell you what my experience has been with the conditions you described. 18000 mi. on my y2k and it would sometimes (not everytime) on a cold( around 32 deg. ) start, smoke blue/white smoke and would not pull a greasy string etc. This happened several times and local dealer had no clue. In a few minutes after being underway it would straighten out and run perfectly. Then one day at a very busy intersection I found out what it was! Dead vp44 injection pump. No other warning signs, smoke or anything, it just quit and would not start. The truck was running perfectly when it quit. This may not be your problem with your truck but it sure would bear checking into before you get hung out to dry like I was. I hate to bring this up but I wanted you to know my experience with white smoke and low power on cold starts. LOL