Hey Dunaruna or good diesel mechanic

[technostingray]

Recently my 6.9 liter Ford F250 diesel started smoking excessively at start up. There is no apparent air in the fuel and compression is still good. Puting the engine uncer load clears up the smoke, but resarting brings on heavy white smoke. The injectors are new and the pump has less than 15,000 miles on it. The glow plug relay is out but the engine still starts relatively easy. Thanks in advance.

 

[QC]

Re: Hey Dunaruna or good diesel mechanic

Well white smoke is associated with unburnt fuel. I would have checked for air first too. Let's assume air isn't the issue and the compression is good (how do you know?). Since it smokes after restart when hot, I would not suspect the glow plugs either. I'm thinking maybe initial timing, or a problem with the timing advance. I am not familiar with how those actually accomplish advance, probably has some sort of mechanical deal and they can and do fail. Who timed the new pump? Did it start smoking in respect to any of the changes? The new pump could be bad as well as new injectors . . . A dribbling injector could cause this too. Does it miss at all? Do you know how to crack a line and find the suspect hole if it is missing?

 

[Chunder06]

Re: Hey Dunaruna or good diesel mechanic

White smoke from a diesel sounds like engine oil is being burnt, does your rig have twin exhausts and if so is the smoke coming from both or only one.

 

[QC]

Re: Hey Dunaruna or good diesel mechanic

Oil smoke should be more blue . . . Also, you can smell if it is fuel. Oh and technically I am nothing close to a "good" diesel mechanic, so don't listen to me . . .

 

[puddle jumper]

Re: Hey Dunaruna or good diesel mechanic

Ckeck for air bubbles in you rad.The white smoke could be coolant in the comustion chamber.

 

[technostingray]

Re: Hey Dunaruna or good diesel mechanic

QC: I know the compression is good because I checked ti with a compression guage, how else would I know? It runs good under power. I have checked for miss by opening the injectors - no effect.. You don't qualify as a dunaruna either, but I appreciate you comments
Puddle jumper:There is no air in the Radiator and no coolant is being lost.
Chunder 06: As QC points out, it is definitely diesel fuel. I have single exhaust.

 

[technostingray]

Re: Hey Dunaruna or good diesel mechanic

Oh, BTW The injectors have not been that recently installed and the pump was timed by the installer. "initial timing"? Please clarify?

 

[QC]

Re: Hey Dunaruna or good diesel mechanic

QC: I know the compression is good because I checked ti with a compression guage, how else would I know?

A leak down test or speculation. Just checking . . .

 

[technostingray]

Re: Hey Dunaruna or good diesel mechanic

QC: I know the compression is good because I checked ti with a compression guage, how else would I know?

A leak down test or speculation. Just checking . . .

How do you do a "leak down test" and what do you mean by initial timing? Does the fast idle switch limit the fuel or the air? Probably not part of the issue but i am really struggling on this one......

 

[crunch]

Re: Hey Dunaruna or good diesel mechanic

I have a 6.9 F-250 and the only time I ever saw white smoke was just before the injector pump went out.... ran good when it first started then went down hill fast.

Unburned fuel smoke is black, oil is blue, white is lean.

 

[QC]

Re: Hey Dunaruna or good diesel mechanic

custombycrunch, black is too much fuel for the available air, white is unburned. Subtle difference, but a little more accurate. Oh, and diesels can be infinitely lean down to idle conditions. That's why they get good fuel efficiency, you don't have to, or ever want to, choke off air to richen the air/fuel ratio.

 

[xtraham]

Re: Hey Dunaruna or good diesel mechanic

White smoke:

 

[crunch]

Re: Hey Dunaruna or good diesel mechanic

QC, I stand corrected.

xtraham, now that I think about it, I saw white smoke one other time, it's when I got a load of water with a fill up and it over whelmed the water separator before I could shut it down.... just a thought.

 

[technostingray]

Re: Hey Dunaruna or good diesel mechanic

White smoke:
Caused by unburned fuel passing through the engine. Some white smoke is normal on cold start-ups.
Excessive white smoke could be an indication of inoperative glow plugs, loose injectors, low compression from worn rings or bent connecting rods, or coolant leak into the cylinders.
repair the glow plug system and see if that corrects the problem

This looks lie a cut an paste from a website. I reiterate:
The smoke goes away when under power, smoke returns when restarting the engine at operating temp;

 

[Plainsman]

Re: Hey Dunaruna or good diesel mechanic

White smoke:
Caused by unburned fuel passing through the engine. Some white smoke is normal on cold start-ups.
Excessive white smoke could be an indication of inoperative glow plugs, loose injectors, low compression from worn rings or bent connecting rods, or coolant leak into the cylinders.
repair the glow plug system and see if that corrects the problem

This looks lie a cut an paste from a website. I reiterate:
The smoke goes away when under power, smoke returns when restarting the engine at operating temp;

Nice of you to slam a guy who is trying to help you.

So what does an engine do under a load that it doesn't do without a load?

 

[QC]

Re: Hey Dunaruna or good diesel mechanic

So what does an engine do under a load that it doesn't do without a load?

More fuel which results in more heat and combustion pressure which results in better combustion.

Techno, think of your fuel injection pump (pump with a bunch of lines, right?) as a distributor. It has to be "initial" timed to the cam and crank combo. And then, like a distributor, it needs to advance in timing as speed and load increases. i.e. more fuel, needs to start earlier. On a pump and line system that is usually achieved by an advance on the drive gear for the injection pump. This may have some gears and flyweights and springs and stuff. This could be installed off a few degrees or stuck advanced.

None of this is still proper diagnostics. Sounds like we have eliminated compression, fuel (you seemed to indicate multiple tanks) and air, but I am not convinced we have eliminated heat although the white smoke at restart would seem to indicate we have.

I am still leaning toward timing and/or a dribbling injector at low idle delivery. Just things to think about. I am more inclined to think timing as it is isn't missing . . .

 

[Plainsman]

Re: Hey Dunaruna or good diesel mechanic

So what does an engine do under a load that it doesn't do without a load?

More fuel which results in more heat and combustion pressure which results in better combustion.

Techno, think of your fuel injection pump (pump with a bunch of lines, right?) as a distributor. It has to be "initial" timed to the cam and crank combo. And then, like a distributor, it needs to advance in timing as speed and load increases. i.e. more fuel, needs to start earlier. On a pump and line system that is usually achieved by an advance on the drive gear for the injection pump. This may have some gears and flyweights and springs and stuff. This could be installed off a few degrees or stuck advanced.

None of this is still proper diagnostics. Sounds like we have eliminated compression, fuel (you seemed to indicate multiple tanks) and air, but I am not convinced we have eliminated heat although the white smoke at restart would seem to indicate we have.

I am still leaning toward timing and/or a dribbling injector at low idle delivery. Just things to think about. I am more inclined to think timing as it is isn't missing . . .

So it looks like he's geting the same amount of fuel with or without a load?

What causes this?

 

[DJ]

Re: Hey Dunaruna or good diesel mechanic

I am a Master Certified Diesel Technician (by International-makers of that engine) but I'm not going to be slammed or accused of a cut and paste. Besides, what's wrong with that?

I thought better of my first response. I participate on this board to try and share knowledge.

Assuming your engine is healthy- good compression, no coolant loss.

One or all of the following issues is most likely causing the white smoke under no/low load.

1. Initial "pin" timing is off. This timing is set at time of pump installation. If it is off, it will cause a low fuel or overfuel condition at low or no load. (Idle and high idle). High idle is WOT with no load.

Under load the governor has more control over the fueling plus, you are using more fuel for power. Thus less, or no, white smoke.

2. You have dripping injector(s). At idle-no load- the dripping will cause white unburned smoke. At load, the fuel is burnt, as it is meant to be.

3. The governor, itself, is faulty. In other words it is slightly hung up, at idle, causing an overfuel condition.

My best bets, without seeing it, are in the order presented.

 

[crunch]

Re: Hey Dunaruna or good diesel mechanic

I am a Master Certified Diesel Technician (by International-makers of that engine) but I'm not going to slammed or accused of a cut and paste.

DWJ, would you please look at the thread I started about my clutch problem, I won't slam and any C/P is info... and info is good 8)

 

[Dunaruna]

Re: Hey Dunaruna or good diesel mechanic

[colour=blue]Sorry Ray, diesel isn't my thing. But I must admit, when I read your post my first thought was an injector with a prostate problem.

QC and DJ are far more qualified than I. My advice is to heed their advice.