I am quickly becoming an urban menace. My truck's MO, for the last 20,000 mi or so, has been to smoke at idle when cold and then clear up. recently the cold idle smoke has increased by a large factor (but still mostly dissapears when warm) and...it has begun to smoke whenever I release the accelerator while still leaving the clutch engaged (pretty much in any gear at any speed, warm or cold). No smoke uphill or at high speeds, only when I start to slow down. I am guessing the injector pump is to blame. Just adjustment or is it trash? Note: this truck has been running on biodiesel for about 2 and a half years (40-50,000 mi).

Also...who makes the best Maint/Tech manual for the 7.3l of an '88 variety?

Cheers

 

What color is the smoke?

Blue = oil
Black = incomplete combustion
White = unburned fuel or water vapor

 

The smoke is white.

 

Whit indicate water, you may have a cavitation wear through, unfortunately common to the 7.3's. Did you use the coolant additive to try to stop the cavitation?

 

If it was water wouldn't I notice some loss of fluid in the radiator? I haven't lost even the smallest amount.

I think that it is fuel as my truck, being bio-d, is pretty ripe and, having been engulfed in it on a number of occasions (picture putting your head over the stove vent of a cheap chinese restaurant) the smoke seems to clearly be smoke. Maybe I am overestimating my ability to tell...

 

Perhaps being bio, it smokes different too. I guess more diagnosis will be needed to help determine. I am planning on trying straight wvo, so I have some to learn on this...

 

Yeah, it sounds like a fueling problem like bad injector, perhaps. Especially since you aren't using any coolant. Does it seem to be misfiring at all? That usually, but not always, happens with a bad injector.

 

Yes, it is misfiring. Definitely this smoke has been simultaneous with rougher running. How would I go about determining which (if any) injector is bad?

 

You loosen each injector line and listen like you would pulling a spark plug wire, but I would recommend just doing them all, not really that expensive, if you go rebuilt.

 

If you have access to an infrared heat gun, you should be able to tell which cylinder isn't firing by shooting close to the heads on the exhaust manifolds. The bad one(s) will read significantly lower than the rest with the engine running.

 

I recommened checking your air cleaner and running some deisel injector cleaner, because a dirty air cleaner will restrict air and less air = less complete combustion. I havn't had any smoking running a k&n and injector cleaner every 4th tank (85+ redline works good). just a thought

 

I had an injector shop tell me the IP would need to be replaced for a similar problem. He said the advance mechanism wasn't working correctly. I asked him how that was effecting the operation. He asked if I was seeing white smoke at startup, then it goes away. This is what I was seeing. He also said if I didn't mind the little puff of smoke, not to worry about it for now, but eventually I would need to replace the IP. Since I'm still getting better than 18mpg around town, I'm not going to touch it!
Brent

 

"Perhaps being bio, it smokes different too. I guess more diagnosis will be needed to help determine. I am planning on trying straight wvo, so I have some to learn on this..."

I use biodiesel in my '93 F-250. It doesn't smoke. Biodiesel won't by itself cause smoke. On the contrary, it cuts soot by 90%.
I also use a wvo/diesel blend. Don't bother trying wvo to cure the smoke.
#1. Can only use <=50% wvo in a stock, unheated fuel system.
#2. Has similar smoke production of biodiesel, ie, very little soot.

 

Bio wreaks havok on the injection system, you probably need a new inj. pump.

 

Where did that come from? What kind of problem would you expect?

I have heard of BIO attacking some old rubber and gelling in cold weather, anything else?