Summer's here and NOW it smokes?

[JohnE]

Something's funny with my morning Cummins. It is finally enough summer so the grid heater very rarely come on, but <b>now</b> it is starting to smoke on the morning start & idle. I noticed a very light grey haze the past few weeks and dismissed it as temperature & humidity related, at first. This morning it was a hazy blue and the heaviest to date.



Before the smoke pattern, I did notice it had a hesitation similar to a spark ignition engine on initial startup. The stumble disappeared in less than a minute. Well, the stumble is gone, but the smoke is here. At least the neighbor's will be happy thinking I'm spraying for skeeters.



I've read before that blue smoke may be a sign of retarded injection timing. How does a gear driven injector pump slip to retard? Is it paying me back for all the winter starts of pushing that cold diesel fuel through the veins?



If I have delayed injection, what is the factory setting and what is the correct setting? My truck is stock, but will soon get a mild TST upgrade to the 230/605 (maybe a bit more) fueling. I also want to up the high speed cutoff to around 3,000 RPM. I only want a good reserve for towing, not get escorted home by the local police or get invited for a free night lodging in the greybar hotel...



If it keeps this up I'll fail the opacity test at emissions. NO wait! I don't have emissions here! Phew!



Thanks



John

 

[Jeff H]

Blue Smoke

My truck has always kicked out plenty of blue smoke on cold starts. Even when its 90 degrees out side it will still kick out some blue smoke. It will clear up as soon as I hit the road. A few years ago I did have the timing bumped up. It still smoked. You may want to check your fuel pressure to be sure it builds up soon enough so that it will idle smoother sooner. It probably would hurt to have the timing checked and set up at around 14 to 15 degrees BTD. Also have you done a valve adjust on it yet? That might be another thing to do. Also throw away the valve cover gaskets. Cummins have udated ones now. Made out of better material and are gray in color.

How do you like living up there? I've got some friends that live west of Bemidji near Solway. I like it up at there its so peacefull.

 

[JohnE]

Jeff;



I grew up around here so I'm home again after 16 years in the Pacific NW. I wish I could have brought the NW Bombers along with me, but I don't think any would budge.



I got white smoke on <font color=blue>COLD</font> weather starts, but as it warmed this spring it went to a very light grey haze for a few moments. It just started this blue fog stuff and has never acted as this before.



I had a preventative checkup, including fuel system check & valve adjustment, performed in December before making the drive from Seattle to here. The <em>Shop</em> loved the preformance of the truck and besides adjusting a couple valves fixed a small turbo boost leak. It normally runs very well.



BTW, the truck is 97, 2500, auto, stock, and 62k miles. Last mileage check was 20-21 mpg combined highway and my 2 mile commute.

 

[The patriot]

Mine smokes a bit. I think it's normal.

Have you replaced the fuel return line? Mine smoked a lot, and missed. It was such a small leak, I didnt see any fuel dripping. Just big enough to let air in my fuel pump over night.

Eric

PS Jeff, have you tried Beano?

 

[illflem]

Mine also smokes on a no block or grid heater start. It seems there is a temp range of about 50°- 80° where it will do it. Think about it, your EGTs at idle are about 300°, takes a moment to reach those temps till the engine runs efficiently. Smoke is normal, though mine seems to smoke more on start-up with the cat missing.

 

[Ken]

Just a quick question why should your truck smoke blue smoke during startup? You dont think that would be oil leaking past the valve guides. ? I always thought that Cold smoke was more of a white color. Just asking... .

 

[JohnE]

Eric;

That's a good point on the fuel lines, especially the return. I've checked them by hand from rubber to braided steel to the connect points and everything feels OK, but I should probably just do the complete makeover. I normally have clouds of white smoke after changing a filter and running fuel starved. Maybe it turns blue in the summer?



Ken;

The first question from my Cummins mechanic buddy was &quot;does it burn oil?&quot;. Well I don't consider a quart in 3,000 burning and neither does he. He's still thinking about it, but I will suggest the fuel line issue.



Bill & Jeff;

My truck has always exhaled smoke on startup. Cooler weather was whiter and warmer weather was <font color=#808080>greyer</font>. This <font color=#4682b4>BLUE</font> stuff is a new one to me. I do have to crank it more than others on startup. I mentioned that as possible problem at my tuneup last year at <em>The Shop</em>. They didn't find any problems at that time.



Hopefully, I'll get a chance to check it this weekend with my brother as he's a diesel head, too. Maybe my Cummins buddy will have an ace up his sleeve, too



I'll keep you posted.



thanks

John

 

[Missouri Mule]

JohnE,



Check out return fuel valve with a fuel pressure test. As I reall a bad but not to bad return fuel valve can cause smoke (blue, white or black).



As far as timing slipping to retard. I think I read it is the delivery valves wearing down, if not the delivery valves it is something in the injector pump that you have to reset the timing as it wears.



I will try and find TSB on fuel return valve and see if it includes blue smoke.

 

[Ken]

Nope if your problem is what I suspect it is it would not be "burning oil" It would be such a small amount and only happening during start up after letting it set a little while. It really sounds to me like worn guides. But I have been wrong before. If this is in fact the problem you would never notice the consumption of oil on the stick. Because the actual consumption is so small

 

[MidwestMotorman]

maybe something simple

I normally post on the 24V section, but I will try to help here.



When is the last time the fuel filter was changed and/or checked for water and other junk in it?



Some blue haze is normal, and occurs on an engine with low miles. The rage with the 24V guys now is cleaning the IAT (intake air temp) sensor. I do not know if the older 12V have this little bugger. The sensors were getting dirty and/or bad, causing the manifold heater to run or not run when it should be. The sensor will make the computer think the engine is warm when it is not, or cold when it is not. This in turns caused smoke, rough starts, and bad mileage.



I guess that is my two cents worth, but my 99 24V was smoking (bad) with blue haze when there was water in my filter. It also smoked blue after about 10ooo miles on the clock and did not quit. Good luck with your problem.



P. S. My blue haze was not oil related, as I use a quart of oil in 8-10 thousand miles.

 

[Missouri Mule]

John,

In Manual it states a defectrive injector pump or misadjusted timing can cause starting problems or prevent engine from revving up.

Also surge at idle, rough idle( warm engine), low power, excess fuel consumption, poor performance, black smoke from exhaust,



blue or white smoke from exhaust, incorredt idle, or max speed.



If you have some of the other symptoms timing mite be off.

Hope fully not bad injector pump.



Will keep searching for blue smoke.



Fuel return valve symptoms did not include blue smoke.