The smoke smelled like diesel fuel. No CEL and no codes. I was planning on pulling #7 & 8 glow plugs tomorrow and checking for coolant with a boroscope just in case my egr cooler is cooked.

 

You need to pull the EGR valve and look into the EGR Valve chamber in the intake manafold. To verify a bad egr cooleer
Hows the coolant leval it would be losing coolant to if the egr cooler was bad.

Smoke with the smell of diesel fuel is normaly injector relaited

 

I pulled the EGR valve and cleaned it this morning, no signs of coolant. The coolant level has been just above min for the last couple monthes. No bubbling in the degas bottle. Maybe I will pull all eight injectors and check cylinders for fuel, inspect injectors and replace the o-rings.

 

ya if you pulled the egr valve and didnt find any sign of coolant the egr cooler is likly ok.

Im thinking injector or bad injector o-rings

 

If we had the proper navistar/ford software at my work, I would have done a cylinder cutout test when it started acting up. Would have saved me from guessing and pulling all the injectors. It was a good thing I cleaned the EGR valve anyways, it was pretty carboned up.

 

If you know someone with an AE (Ford Enhanced Bundle) the truck should have logged a contribution balance code on the injector(s) that were weak/leaking. This may sound a little crazy...but you could pull all eight glow plugs...then after they're out turn the engine over. If you do have a cracked injector...the fuel will come pouring out of the glow plug hole of the offending injector. If the engine did hydrolock that will give the fuild a path to escape without damaging the engine. Yeah, injector o-ring kits are only $3-$5...but the rear valve cover nuts are a PITA to get to (or at least if your hands are as fat as mine) so why pull injectors that you don't have to?

 

That's a good point. I'm used to working on heavy duty diesel engines in highway tractors so i'm not used to dealing with glow plugs. Are they reletively easy to r&r? I heard that it is common to break the glow plug harness due to being brittle from heat?

 

You can R&R 'em...just take your time and be careful. There are guys that have pulled them off and not broke anything. Others (like myself) well we'd tear up a box of rocks...or so it seems.

 

It's funny, at work I'm the most patient person in our shop (probably because I'm getting paid to do it) but at home I'm like a bull in a china shop. I just want to get it done. My wife refuses to help me anymore.

I'll try pulling the glow plugs tomorrow. Even if there is no evidance of a leaking egr cooler ie coolant in the intake at the egr valve, it would be extra insurance to check for coolant with the glow plugs out.

 

Is it consuming any anti freeze could need both egr and head gaskets and the new up graded head bolt If it seems like alot of white smoke . take a smell of the exuast if it smell sweet it could be a head gasket. or egr

 

I'd check what ever comes out of the glow plug holes when you turn the engine over...that will tell you where to look. It possible your batteries aren't strong enough to spin the engine over (if they haven't been charged lately)...but from what your saying, it sounds like you've got an injector issue. Could be a cracked tip (it just happens) or the lower o-ring on one has given up the ghost. A coolant leak is possible, but not likely; you'd notice the loose in coolant and the exhaust would have smelled "sweet" before the truck had gotten to this point.

 

Please excuse my diesel ignorance, but on a related subject, what causes an injector to fail? I'm trying to learn about fuel injection and the ones I've inspected on gas engines seem very simple, but on diesels I seem to hear about injectors sticking and failing frequently. Are they different than automotive ones?

 

They are very different. The ones in our diesel trucks run at a higher pressure (3000 psi injection) than a gasser and in the case of the 7.3L PSD and 6.0L (HUEI engines) they use high-pressure engine oil to "fire" (inject) the fuel into the cylinder.

As far as what makes 'em fail...it can be several things. Low fuel pressure (45 psi is bare minimum) will cause extreme wear to the insides of the barrel where the plunger moves. The tips can crack (some for no-known reason) or o-ring failure are some of the more common issues.

 

Also, in a gas engine the air/fuel is ignited with a spark and a diesel engine it's ignited by the heat created from compressing the volume of air in the cylinder. An injector in a diesel engine is required to time, meter and increase fuel pressure.

As zhilton said, nozzle opening pressure is usually around 3000 psi and increases during the duration of injection. A gas injector is usually around 30-50 psi and the fuel pump/regulator dictates injection pressure. A HUEI injector uses a high pressure oil pump that increases oil pressure in the injection circuit and acts on an amplification piston in the injector, which turns 500 psi of oil pressure into 6000 psi of fuel pressure. The timing, beginning and end of injection, in a HUEI system is infinitely adjustable by the engine ECM, which controls the opening and closing of the oil solenoid in the injector, allowing oil to act on the amplification piston and direct it away. The metering of fuel is controlled by the engine ECM, which controls the opening and closing of the solenoid in the injector fuel circuit, allowing the required amount fuel to enter the injector. A gas injector is basically a solenoid that opens and closes to allow fuel into the intake manifold at the correct time and orifii to atomize the fuel to mix with the incoming air.

The high fuel pressure and very small orifii in a diesel fuel injector nozzle are required to atomize the fuel fine enough to allow for quick and complete vaporization of the fuel once it is injected, so the heat created by compression can ignite it (diesels don't have a spark to ignite the fuel).

A diesel fuel injector also has to withstand combustion pressure as most modern diesel engines are direct injection, meaning the injector injects directly into the combustion chamber. Whereas, until recently, most gas engines inject the fuel into the intake manifold upstream of the intake valve to mix with the incoming air.

 

Thanks guys, I really appreciate the info. I like knowing how stuff works and this is one of those things I never could find a way to ask and be able to get a straight answer. Thanks again!