Blue Smoke and Loss of Power

[swamp rat]

Coming to work this afternoon, I had a sudden loss of power and several large puffs of blue smoke from the exhaust. Shortly afterward, the power came back up and the smoke dissipated. As an aside, it seems like my turbo has been a bit slow to spool up lately, and cold starting is somewhat hard with a slight haze of blue smoke. Since I haven't gotten around to the gauges yet (still on my early X-mas gift list to myself), would anyone care to speculate as to what the cause might be? My suspicion is I may have lost the seal between a rubber boot/clamp somewhere between the turbo and intake. Does this sound probable to you guys?



TIA



Swampy

 

[Bob Wagner]

get those gauges gauges gauges

and yes it does sound like an air leak...

 

[Missouri Mule]

swamp rat,

Seems to be fuel problem air could be leaking into fuel system.



Usually black smoke when clamp becomes loose or hole in hose.

This happens a lot at the intercooler connection on intake maniflod side.

But it usually doesn't fix itself, the driver has to get out and tighten the clamp.



Blue smoke is not good. I think there was post on this recently.

Don't remember if problem was solved.



Another thing to look at is the afc line/hose that goes to waste gate solenoid this mite be blowing air.



I know blue smoke is associated with the injector pump(if is going bad) but believe it can be symptoms of other components going bad.



How is the dirt problem did you get it cleaned up? I t seems that since it lasted a short time that a piece of dirt gat lodge some where.

Did you get some bacteria killer for diesel fuel and put in the tank?

 

[Evan A. Beck]

Well, typically if it is a boost leak you will experience the loss of power, and black smoke--not blue. Blue smoke is usually caused by one of two things... Oil in the cylinders, or retarded timing. Since it sounds like an intermittent thing, I am going to say that it isn't the timing. A good way to see if your timing is retarded is on a cold start, rev the motor to 1,800 RPM. If it blows a lot of blue smoke, then your timing is a little off.



Oil in the cylinders can be a little more tricky. Again, since it is an intermittent thing, we can say that your rings are not going out... That's pretty rare on a Cummins. What I think is going on, is some oil got into the internal fuel system in the injection pump. I have seenthis happen before, and it starts out only happening every now and then, but gets progressively worse. Somtimes what happens, is some seals in the injection pump start to leak, and engine oil can get into places its not supposed to be. The solution is to pull the pump off and have it taken care of. Not a major thing.



Did it run rough at all when it was doing it? Do you have gauges, and if so, what did they say when it was happening?

 

[Extreme1]

Wouldn't a turbo oil control problem cause blue smoke?

 

[Evan A. Beck]

Yeah, but it would have to be quite a bit of oil... Plus, it would be smoking all the time, more than likely.

 

[swamp rat]

Thanks for that reminder Bob. The gauges have been bumped to the top of the todo list now that I have some new skins on the wheels. Reminds me, I need to update my signature again. 285/75/16 Continental A/T's in 8ply.



Mule, I poked around under the hood during break last night, and I found one of the rubbers slipping a small bit going into the intake manifold. Still hard to start and turbo seems to spool up only slightly quicker, but it still struggles on the low end till it tachs about 1500-1600 then it starts coming in. About 2k the turbo noise is noticeable but not overbearing.

Yep I finally cleaned everything up and pieced it all back together. The tank was spotless inside when I finished. After I revamped the tank connections, the lift pump draws fuel much easier. Before, it was sucking air around the supply tube coming out of the tank. The new QD plastic insert clips work perfectly. Just filled up at Speedway in OakGrove, KY Thurs, and have burned 1/4 tank in 235 miles. Mileage appears to be pretty decent. More on that as the gauge drops. 10-4 on biocide and cetane booster, I dosed it upon fillup. I had a small amount of older but clean fuel left in the tank



Evan, I think your diganosis may be pretty close. When I left from work last night, upon cold cranking I ran her up to 1800 and had lotsa blue smoke for several seconds. When she smoothed out the smoke dissipated but still left a slight tinge coming out the pipe as best I could see. It was a bit dark back there. As an aside, I know the low idle needs tweaking. Acording to the dash Tach (not the most accurate measurement I know) it reads about 675-700rpm. I was going to bump it up as close to 800 as I can using the OEM tach.



You scare me when you mention "Injection Pump". (read: cold shiver up spine, extreme pain in wallet). Could those seals you mentioned just be a bit dry from sitting for an extended time engine not having been lubed by a running engine, thereby allowing some oil seepage into those places where it ain't sposed to be? or (SHUDDER) something more injurious to ones sanity and fiscal wellbeing?



When the smoke & power loss ocurred Y-day afternoon, it was more of a burp-poof-coast then powered back up, but I was also rolling at 55 on the big road easing out of the throttle for slower traffic. Usually when it burps like that (very rarely) I am slowing down or stopping for a light or about to turn a corner and is almost always proceeded by a marked decrease in RPM's. If I notice it early enough, I can touch the throttle to keep the R's up. This time it made no diff. And as I said earlier, gauges are now #1 priority on my personal X-mas list for myself, even before the shocks.



Thanks to all for your ideas, suggestions and assistance. It is greatly appreciated.



Swampy

 

[WyoJim]

Change the fuel filter. If you just did, do it again.

 

[Evan A. Beck]

Swampy,



Go head and kick your idle up to 900. They run real nice there, especially in the coldest winter months.



A slight tinge of bluw/white smoke when starting cold is normal. Both my 24V trucks do it, and it goes away in a few minutes.



As to the injector pump concern, seepage due to poor lubrication is possible, but doubtful. To run properly, the P7100 has to be calibrated just right... I have seen them with some pretty out of balance cylinders, and can cause low mpg, but with no smoke or any other symptoms. JUST low mpg. These things can be finicky. It does sound like you have an injector pump problem, but it doesn't sound serious. Before going to the injector pump shop, have your timing checked. This could be the whole problem.



Does the engine shudder or miss at all? This will be the next symptom of an injection pump that is out of balance or has some seals leaking. MPG still ok?



You mentioned hard to start too... Check your fuel pressure, and timing. If all that checks out ok, it's probably going to be injector-pump related. Also, do a valve adjustment for peace of mind.

 

[swamp rat]

Shudder & Miss

Evan it doesn't seem to shudder or miss. Its just occasionally it quits pulling under light or steady throttle or moreso just as I let off to slow down to stop for a light. Mostly the latter, but if I can slip my right foot off the brake and over to the throttle for a split second, I can bump the R's up to keep it from stalling or dropping below 500rpm. Sometimes it recovers on its own sometime not. That is what lead me to hope it is only the low idle.



MPG appears to still be up there @20 (less than 1/2tank burned per 390 miles) empty running normal to semi-heavy foot. New I got a few tankfuls around 24 empty with tailgate down and conservative driving.



I'm about 6k away from due time for my third valve lash, and to my knowledge the timing has never been adjusted since factory. With the proper tools, I have no fear to attempt the valve lash myself (seems rather straightforward even for an Diesel-idiot like me ), but the timing part rattles me a bit. May have to leave that to the pro's the first time.



Hope my lift pump pressure is up to snuff. I'd hate to knock some 5 Star Noggins around for selling/installing a bum pump last year. Still have the original just in case.





Thanks again Evan for some great advice.



Swampy

 

[Evan A. Beck]

Here's a tip for doing valve lash adjustment that will make it go faster...



Turn over the motor with a 7/8" socket on the alternator pulley. One other thing, to locate TDC @ #1, watch #6 until it's at crossover (one rocker going up, the other going down at the same time). This is called the "companion cylinder" method. Adjust the proper valves, then rotate the engine over until #6 is at TDC, which means #1 will be at crossover. Gap the intake valves at 0. 010" and the exhaust at 0. 020. "



When at TDC for #1, check:



Intake 1, 2, and 4

Exhaust 1, 3, and 5



When at TDC for #6, check:



Intake 3, 5, and 6

Exhaust 2, 4, and 6



Anyways, back to the issue at hand...



Before reading further, kick up your idle to 900.



Before you have the timing checked, get the fuel pressure checked. If it is low, swap in a new overflow valve. They are about 80 bucks, kind of pricey for a fitting with a spring in it. If it is ok, then you can rule that out as a possible cause for your problem. Be sure to do tests @ idle and under load. Idle pressure should be 18-23, and 26-30 @ 2,000 RPM.



At idle, pinch off the return fuel line for a couple seconds, and watch how fast the fuel pressure comes up. If it comes up right away, the the output of your pump is probably ok. If it is cluggish to come up, then your pump is bad. It should his 50+ psi within about 1. 5-2 seconds.



If all the above checks out ok, then have your timing looked at. It is a pretty involved process, as you have to take out #1 intake pushrod, and set up a TDC locator, then you have to take out the #1 delivery valve on the injector pump. After setting up a few dial gauges, you can check the timing. You may want to let Cummins do this, or a reputable diesel shop who is familiar with the P7100 pump.



Let me know what your fuel pressure comes out at, I am pretty curious what it is. Hopefully, a simple fix will cure your problem. How many miles are on the truck, anyways?

 

[swamp rat]

Ahh! More good tips for adjusting the valves! Never can have too many good ideas that make life, work, and play easier and simpler.



I plan to get right on the low idle tomorrow since I finally have a day off. I'll go from there following the list. I had a feeling I should have ordered an overflow valve last month when they were on special for $45. Snooze and Loose I guess.



Speaking of fuel pressure and gauges, I'm in the market for a good dash type gauge. Any suggestions? I am partial to the ATM Z-series, but they don't have anything that appears to be suitable. Wished I could afford the SPA but ouch!



BTW, the truck has a shade over 66k miles now, but due to a shoulder injury, it has set up since last year ago Jan-May and again from Sept. til May due to a leaking return line (now repaired). Had fun getting the crud out of the tank, and changing pre-screen and heater O-rings. So much so that I feel as if I am fairly proficient in that area now.





Swampy

 

[swamp rat]

Fresh out from under hood for the night!

New fuel filter, Low idle bumped to 1000, will tweak it back down 100 R's later. Still hard starting cold. Warm starting much better, bump and run even after 10 minutes sitting. RPM's run up quicker and smoother w/no load. Turbo seems to spool up better, but haven't had a chance to take her for a test ride, just up and down the driveway 1/2 mile. (I have a very long driveway with as much privacy). Still getting a lot of smoke more white than blue on cold start especially when I romp the throttle. Will have more info after I get to work tomorrow evening.

 

[Missouri Mule]

swamp rat,

Usualy white smoke is symptom of cold weather start where the intake heaters are not working correctly but tempature should not be that cold up there. Is it dropping below 60 degrees?



Have you tried priming the pump when having hard starting problem? If engines starts easier after priming you have fuel problem.

I think when fuel supply is on low side at start up white smoke is present also.



Have you checked oil drain holes in head are not plugged? If at start up you are getting blue smoke( and oil in cylinder can be cause) maybe the oil draining into cylinder thru valve quides.



Have you turned up AFC wheel? If you turn it toward engine 20 times you will get more fuel at low rpms which in turn will give more boost early at low rpms.

 

[swamp rat]

Bill,



Cold weather here in Tenn. is the least likely culprit right now. We haven't seen temps under 70 degrees for quite a while, this coming Monday night may be the exception. 68 is supposed to be overnight low.



I've tried the priming plunger but I probably give up to quick cuz of the difficulty involved with me being able to stay in the needed position long enough to push the primer more than a dozen or so times with my thumb. However it does seem to shorten the length of time it takes to fire up but only slightly.



Fuel level has been no prob as the tank is/was no less than 1/3 tank even early on before I dropped the tank to clean out the crud.



You may have hit upon something about oil possibly draining back into the cylinders. Since the truck did sit for quite a spell, it may be feasible a few of the valve springs may have become slgihtly weakened from being under compression for an extended period. This might cause a low compression condition which could be responsible for the white smoke and hard to start condition.



Since turning up the idle, the other problems have diminished drastically. The engine did stumble and die once last night while waiting in line at McD's drivethru, but the power seems to be quite a bit better. It was still hard to start after dying at McD's, but it has only happened once since bumping the idle.



Throttle response is excellent in 3rd from 1100 RPM up, pretty good in 4th from about 1500-1600R's up, and the turbo starts sounding off pretty good too. In 5th gear, it still seems a tad sluggish from what I remember it being till I hit 2000+. Maybe my memory ain't so good anymore. and I am running the 285's with 3. 54(5) gear, one or the other I forgot. She will git up and run after hitting 75mph.



As an aside, I did pour in a half a bottle of FPPF last night. I'll pour in the rest Monday when I fill up again.



The AFC is virgin, but maybe not for much longer.



In any case, I sure hope I am getting closer to normal, and I definitely appreciate all the help and suggestions. Definitely the best $35 I've ever spent.

 

[**ICEMAN**]

been where you are and it was the overflow valve that was shot. you know how to check it?

 

[swamp rat]

Thanks Iceman. I was contemplating a new overflow anyway. I pulled it a while back when I installed the Prime-Loc. Then the engine would not fire up at all. The spring had compressed to a shade over 1/4 inch. I stetched it back to 1/2 inch and it started but was a hard start. Guess I'll give Piers a holler Monday to order a new one. (shoulda done it last month when the special was on, but procrastination set in)