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Followup To
Question -
Van,
At the beginning of my problem I started out with a rough idle and some light blue smoke. The truck has 270,000 miles on it and had been running great until recently. Then it got to where it wouldn't start.
So I started working on my 1983 ford F250 with a 6.9 Diesel. At first the glow plugs would not come on and stay on properly (indicator light would stay on about 1 second and go off) so the engine wouldn't start. I finally got my glow plug circuit corrected and after replacing the glow plugs, glow plug controller, glow plug relay. Then I wasn't getting fuel to the injectors so It was about time to change the injection pump, so I did and I replaced the injectors too. I am still puzzled. I still couldn't get it started. I probably replace alot of things unnecessarily, but the pump usually goes bad about every 70K so I figured I would do the injectors with it this time. It appeared I wasn't getting any fuel so I started looking. I found a crimped hose (should have looked here first) near the tank selector solinoid. Replaced and Staighten all the fuel lines out and by-passed the fuel water separator temporarily (could not get it to fill properly-acted like there was a leak-sucking air) when I finally got the engine started again, it is running smoother but still exhausting a light blue to white smoke. I did a power balance test and couldn't detect much difference on any one cylinder. Footnote: I broke a vacuum connection of the transmission control selector on the side of the injection pump, but this should not have anything to do with performance of the engine (it is seperated by it's own vacuum pump) but I am at a loss to determine the cause of the blue smoke. When all of this first started idleing rough, I took it to a diesel mechanic. He did a compression check and said everything looked good (?).
I have a lot of tools, I am a capable mechanic, I don't have many diesel tools, especially a compression tester. I do most all of my work because I enjoy learning as much as I can about cars and trucks, gas and diesel. When I changed the injection pump, I made certain the timing lines were lined up properly (It really only fits one way when you take the old one off) so can you help me diagnosis the smoking problem?
I will buy a compression gauge if I must. I have compression testers for cars that goes up to 300 psi, but I don't know what to expect with the diesel (800 psi?).
One other bit of information, I did have a lot of carbon build up on both the injector and glow plug for the right rear (passenger side) cylinder when I removed them. The engine ran hot once when the block heater plug rusted out and dumped all the coolant.
Thank you for your time and I hope I described enough of what I went through and what is going on to help you help me.
sincerely,
Roger Carlton
five_w_coupe@yahoo.com
Answer -
Hello Roger,
I wouldn't run down and get a compression tester. You might want to make a little adapter to screw into a glowplug hole, and connect some compressed air, just to listen to the crankcase, intake, and exhaust, to see if you hear any big leaks.
But I would suspect that an intake valve guide may be worn enough that a little oil is being drawn in and burned.
I can't immagine that I would overhaul it for that. I might try advancing the timing just a bit.
Van
Thank You Van, but It is a Cloud of smoke coming off the exhaust pipe that doesn't seem to clear up much as the engine warms up. I will advance the timing a little and see if that helps and I will check the blow by as you suggested and let you know how that goes. But I am talking serious smoke, like a mosquito fogger.
Roger
AnswerSay Roger,
I'm just not familiar enough with that engine to help much, but you could have an oil ring broken or stuck, and still get a good compression test.
And a really worn valve guide could let it draw a lot of oil in and burn it.
Removing the valve cover may let you wiggle a valve stem to see if there is anything obvious, but I wouldn't get my hopes up.
With the intake manifold off, it may be possible to look at the back side of the intake valves, and see if one is more oil coated than the others, which could call for a valve job, but even with the heads removed, you can't see the condition of the rings.
A burned valve, though, could cause a cylinder to not fire, or incompletely fire, and smoke a lot, plus rough running. You should be able to narrow that down though, by cracking the fuel lines.
Wish I could help more,
Good luck,
Van
