1986 econoline 350 6.9idi experiencing steady blow by under load. Thoughts?

[Nick Dumas]

Hey folks I’m the new owner of a 1986 econoline 350 6.9idi extended roof camper van, also new to this forum.
I have steady/heavy blueish-grey smoke when the vehicle is under load.
Just replaced CDR (from ford) as most people say, and I’m experiencing the same amount of smoke from what I’ve seen.
Some folks including the previous owner (but he was shooting in the dark by his own admission) suggested replacin the valve cover gaskets.
The vehicle has decent power for its age and weight, starts with a shot of smoke but idles with no smoke.
Has 220,000 km on her so there’s no doubt she needs work.
Any help or tips are appreciated, and if this has already been covered in a different thread by all means my bad. Cheers

 

[IDIBRONCO]

I'll say that you could replace the valve cover gaskets, but first I'd pull the dog house off and look at them closely. If you can see leaking oil, then you'll know that you need to replace them. These engine do have a lot of blow by when compared to other engines. If your van doesn't smoke out the tail while driving normally at highway speeds, there's probably nothing wrong with the little bit of smoke you see at start up. These engines need heat to burn the fuel efficiently and upon a cold start, there's not too much heat in the cylinders yet. By the way, welcome!

 

[Macrobb]

OK, if this smoke is coming out of the exhaust, you have retarded engine syndrome - the IP/injectors are *very* worn, and the timing is extremely retarded.

Basically, it's time for an IP/injector replacement.

Now, it's totally possible to just advance the IP about 7 degrees, which will clear a lot of that up(and give you more power/fuel economy as well), but the parts are still fairly worn.

Oil vapors and such going into the engine won't affect it - these engines will cleanly burn engine oil.

Smoke out the exhaust is one of three colors:
White - unburned fuel generally, due to a cylinder totally not firing. Also can be coolant if it smells like it.
Blue/gray - seriously retarded timing - incomplete combustion.
Black - Over-fueling/too advanced timing. It's carbon from not enough air during the combustion process.

 

[IDIBRONCO]

From how I read this, he's talking about two kinds of "smoke". There appears to be a puff of smoke when the engine first starts (probably black) which is normal, and the other type of "smoke" appears to be the blow by from the engine.

 

[Macrobb]

From how I read this, he's talking about two kinds of "smoke". There appears to be a puff of smoke when the engine first starts (probably black) which is normal, and the other type of "smoke" appears to be the blow by from the engine.

I was reading it as:
Puff of black on startup
Nothing at idle
Blue/gray under load.

 

[Nick Dumas]

Thank you both for the help, it’s greatly appreciated.
As of the moment the only smoke I’m getting is the white/gray.
That’s on startup and under load.
I looked into new injectors and have a set on the way, planning on swapping those and seeing if there’s a difference

 

[IDIBRONCO]

I guess I read it wrong. Oh well. That would be a good place to start. Usually, the pump and injectors wear at the same rate. When one needs to be replaced, the other does too (speaking of the injectors as a set).

 

[Thewespaul]

Water is kinda muddy here.

Blow by is gasses from compression entering the crankcase, smoke out the exhaust is not blow by, since that is gas above the rings/piston.

 

[IDIBRONCO]

Water is kinda muddy here.

Blow by is gasses from compression entering the crankcase, smoke out the exhaust is not blow by, since that is gas above the rings/piston.

I did miss the part of the original post where he said that he has a steady bluish/gray smoke when under a load. He did neglect to say that it was out of the exhaust and I connected the dots to the new CDR.

 

[Thewespaul]

I did miss the part of the original post where he said that he has a steady bluish/gray smoke when under a load. He did neglect to say that it was out of the exhaust and I connected the dots to the new CDR.

Yep, and blowby in the title wouldn’t point towards smoke from the exhaust.

 

[IDIBRONCO]

That too.

 

[Nick Dumas]

Ah I should have specified it was out the exhaust. I now know thanks to you folks this isn’t considered blowby and I’m looking at a fuel/air/timing issue here. I have new injectors just waiting for the rain to stop and I’ll see if those make a difference

 

[nelstomlinson]

I have an '87 F350 with the exact same symptoms: idles with clear exhaust, blue-gray smoke under any kind of load. To advance the timing I need to rotate the top of the IP toward the driver's side of the vehicle, right?

The silly thing burns a quart of oil in 50 miles, so there are some real problems, but it would be nice to clear up the smoke.

 

[Thewespaul]

A clogged cdr can cause the smoking as well as a fueling issue, but typically timing. Towards passenger side is advanced correct.

 

[nelstomlinson]

I took the CDR off mine, just venting the crankcase to the open air, so that's definitely not causing the oil burning.