Troubleshooting missing and smoke on startup - with video
 

Preface: I know there are several threads on this. But I wanted to post a video to get some more specific input.

For the past year or so, my wagon has had exhibited rough starts when cold. Missing several times, plus clouds of white smoke are the norm, especially when cold (under ~ 50 F). In addition, the 617 often misses when hot. I can't figure out the rhyme or reason for this. Sometimes when hot, it idles nice and smoothly at a red light. Other times when hot, it will miss every 3-5 seconds at idle.

Recently, this problem has gotten worse. After I replaced 2 bad glow plugs, the rough start and associated white smoke seems to have gotten worse. I have verified the functionality of the GPs several times -- testing the wiring, and the glow plugs themselves. I even removed the newly replaced GPs and tested them outside the car, just to make sure that they were glowing nice a hot. I am not sure why the rough start + smoke has gotten worse after replacing bad GPs. One would assume that GPs would alleviate problematic cold starts!

I should note that the 617 is about due for a valve adjustment. I know that this should help the smoking issue. But I don't think it would help the missing. In addition, like I said, this problem seems to have gotten about 2X worse immediately after replacing GPs.

In the video, you should be able to hear some rough starting on first crank. To me it sounds like the motor isn't firing on all cylinders. Then, in addition to the white smoke, a few puffs of black smoke will shoot out of the tailpipe. These are associated with the miss. Eventually the black smoke goes away, but the white smoke continues to be expelled for some time.

My current hypothesis is that there's an air leak. I am not sure how to further troubleshoot or fix that. I tightened the connections at the fuel filters, and I have the new-style primer pump. Should I replace all the rubber lines in the engine compartment? Time for new braided return hoses?

Any input is appreciated.

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Does anybody have any advice on this? I'd hate to throw parts at this without further troubleshooting. I'd appreciate any input people may have.

Thanks.

White smoke is either oil or water.

Check the oil cap for color, any water getting in there will cause the oil to turn brown and a bit foamy.

Valve adjustment should help too.

It seems like you might have a bad head gasket or head. Does the motor overheat?

I don't see white smoke, a few puffs of grey which I can't explain. I don't think you have a headgasket problem. One thing I've noticed with my TD is that rough initial running coincides with the hydraulic pump bringing the SLS system up to pressure. If the pressure is low from sitting it appears that the pump puts a fair load on the engine. I've noticed this by putting my foot on the ground while starting the engine cold. I can feel the pump pressure getting up to normal as the car picks up slightly when the pressure gets high. Then the engine runs more smoothly. Not sure if this is relevant to your situation or not.

Diesel Purge? Cetane Booster like Red Line? those are relatively inexpensive things you could try.

Thanks for the replies. I'm pretty sure that the headgasket is fine. This is a low-mileage factory reman. It has plenty of power, good compression (last I checked), and there are no signs of contamination either in the oil or the coolant. It's never been overheated (although my temp gauge doesn't function properly...:eek:)

Kerry, that sounds like a plausible explanation. I rebuilt my SLS pump and valve a few months ago. The system is functioning well. So a well-working (i.e. non-leaky) SLS system is a new phenomenon to me. By placing your foot "on the ground", I assume you mean on the floor of the car, near the pedals?

Injectors are something I've thought about. Perhaps a drippy injector is causing incomplete combustion in one or two cylinders - hence, the smoking and missing while cold. Then, presumably, even the drippy diesel will ignite when the motor's up to operating temp, which may explain a smaller amount of smoke when warm. Still, I don't know why it misses at idle while hot. That's what makes me think there's an air leak somewhere.

Do you think I did something when I replaced the GPs? There was a marked increase in the rough start + smoke after I replaced them. I fear that maybe I pushed some carbon into the cylinder when I put in the new GPs?

No, my left foot on the ground outside the car. It allows you to detect small changes in the height of the vehicle.

I see the typical miss with associated smoke from a cold engine that might not have perfect compression.

Once 20 seconds have passed, the engine settles into a perfect idle. I see no evidence of any miss after this time has elapsed.

There is no possibility that changing glow plugs resulted in additional smoke and/or miss.

If there really is White Smoke at sometimes; as said previously Coolant. But, I have also read White smooke can be Atomized unburned Fuel.
If you having the White Smoke at idle take a piece of Card Board and hold it near the Tail Pipe for a bit.
If it smells like Diesel Fuel you need to investigate why it is not burning.

Also there was no mention of doing the Injector Cutout test to locate a possible Cylinder that is causing the problem.

Maybe the Idle speed it too low for the SLS.

Logically, I too don't see how changing the GPs would be associated with an increase in smoke and missing. But it happened. I thought that maybe some air was trapped in the hard lines (which were removed during the GP swap), and that it would eventually be purged, but that was not the case.

Yeah, I guess it's difficult to tell the exact color in the video, especially with the whitish background of the driveway. The smoke definitely isn't bluish-gray (i.e. burned motor oil), but more of a whitish-gray. I think unburned fuel is more likely.

By injector cut-out test, do you mean cracking each hard line nut individually, and seeing if there is a change in missing and/or smoke?

What is the target idle speed for SLS? 750? 800?

Thanks for the replies.

I had this same problem and had some air getting by the prechambers. I bought new prechambers, rebuilt to spec injectors and new glow plugs. Now I was due so wasn't just throwing $$$ at it. My car has 227K on it and needed these items. It helped a lot. I still have some rough idle in very cold temps at initial start up, but overall the car is much, much better. I saw a post about adjusting idle on the IP too, but I am not familiar enough with the IP pumps and have heard way to many horror stories to be daring enough to try yet. Although mine is showing signs of beginning to leak so I will need to tackle at some point.

I would say that one cylinder has a compression problem. The white smoke indicates the fuel is smoldering, not burning. When that cylinder finally lights off, that's your black smoke, the burning of all the unburned fuel in the cylinder. I would start with a valve adjustment.

"I should note that the 617 is about due for a valve adjustment."

How long since the last one?

Last valve adjustment was about 10k miles ago.

Air in the prechambers? Is that a result of worn injectors, or something else?

It sounds like I should start with fuel delivery & compression testing before chasing an air leak. I'll adjust the valves, individually crack injector lines, and do some research on injector replacement or rebuilding.