I think I may have blown the engine today or else an injector blew apart. I need some help determining exactly what went wrong.

It started about a week ago when I noticed the truck having more smoke at start up than normal. Also I noticed some smoke even whn the engine was warm. Then on the way home tonight I was cruising done the highway when all the sudden it started knocking, I mean really knocking bad. I looked in the mirror and the entire road was smoked out. I coasted to a stop and shut it off.

There wasn't any oil pouring out on the ground, so thats good. Checked the dipstick and the oil appeared normal and it ws still full.

I read somewhere that injectors knock real bad when they go out, but I have no experience with that.

 

Do you have access to a machine that will do a buzz test? What about a cylinder contribution test? What about fuel pressure how is that?

 

What color was the smoke?

 

I don't think its a good idea to start it up again, is it? I don't have access to a macine that does a CCT or buzz test unless you can rent one somewhere.

It was dark so i'm not exactly sure but it was either white, light grey, or blue. I'm thinking it was probably white, but it happened so fast and being dark when it happened i just can't say for sure.

 

Could be a broken nozzle on an injector, or cracked tip over fueling a single cylinder no?

Only way to tell is compression test, and start pulling injectors, hopefully not heads and a motor. Buzz/contribution test would be ideal, but if you don't have a unit I'd take the valve covers off and see what you can find....

 

Yeah I was just doing some reading about broken nozzle springs. Might be the problem. I have been suspecting that I needed new injectors recently. I was hoping it would last just two more weeks when I would be out of school, but that was asking too much of it.

So I'm thinking that I shouldn't try to restart it since it may be a nozzle issue. Is that right?

EDIT: Forgot to mention that it has been idling funny ever since it started to smoke more.

 

It kinda sounded like the truck in this video, but i didn't rev it up at all.

 

the video sound's more like a rocker arm to me.

 

I agree. The knock in that video does not sound like an injector.

 

Well, I am going to pull the valve covers friday or saturday and see if there is any obvious problems. Then do a compression test and go from there.

After some reading the odds are good that the motor is ruined even if it was an injector nozzle failing. I've read about the flame burning holes in pistons or a broken piece of the nozzle scoring the cylinder walls.

Would that cause the smoke that I was seeing?

If no one has any more input, i'll update as i figure stuff out.

 

If it was an intake rocker messed up. They can suck oil into cyl because it has nowhere else to pull from. Not saying it's that but i have see that on gas motor's that came through the machine shop

 

After spending all friggin day getting a usable set up to test compression I realized that I really didn't know what I was doing! When I turned the motor by hand the most pressure I could build was only 65 psi. And that was turning the wrench as fast as I could. If I did it slow the needle on the gauge would only jump just a tick. The air was leaking somewhere because I could here it, but could not feel where. Some I'm sure was around my adapter connections because I ran out of teflon tape.

I'm not sure if this was a good idea or not, but I decided to have my wife turn the motor over with the key (starter) while I watched the gauge. I made the mistake of standing at the passenger side of the motor on the first crank. A huge white mist cloud enveloped me. It scared the crap out of me but after I gathered myself I discovered that it was raw diesel fuel! The source was cylinder #7. So that is my problem child.

We went on the check the compression on the rest of the cylinders. It is hard to see the needle let alone get a decent reading when you use the starter to turn over the motor. I have mixed emotions and confusion about the results.

Most of the cylinders seem to spring the needle to the around 250-300 psi. Cylinder #6 didn't make it over 200 psi. #7 and #8 were both over 300 psi with #8 hitting at least 350 psi. #2 was inconsistent. It showed 250 psi a couple of times and about 325 psi a couple of times.

I know there are several reason for these numbers being very inaccurate. The engine was cold because I stepped on the extension cord to the block heater and unplugged it without realizing it. The DIY adapter was probably leaking since I didn't have teflon tape on one of the connections. Using the starter to turn the engine made it difficult to read the gauge which is really only designed to read static pressure anyway. And lastly the DIY adapter requires the air to move through a 5/64" hole so the piston probably was moving back down before the pressure was equalized between the gauge and the chamber.

So for the long post, but I wanted to include all the details.

So can I take anything away from these results beside the fact that I need new injectors?

On the plus side I didn't come up with a totally dead hole, so thats good. Tomorrow I will pull the injectors. I am curious what the nozzle looks like on #7.

Thanks for reading this and for any input you have.

 

Did you pull fuse #22, or in some other way disable the injectors, for the test? You can also crank the starter by running a jumper wire from the battery + to the small terminal on the starter relay, without even having the key in (be SURE you're not in gear!).

If you have a good tester, it should go up with every stroke, about 8-10 times, then level off, and shouldn't go down in between until press the release button on the tester. You shouldn't have to be watching the needle while you're cranking the engine.

Yes, the fact that they all registered something is good news, but it sounds like the real take-away is that you need to get that tester working better.

 

Did all the rockers look good? Any possibility of a bend push rod? How does the anti freeze look.

 

You are supposed to turn the engine with the starter, You'll never turn it fast enough by hand.....

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http://powerstrokenation.com/forums/...ad.php?t=61406


Sounds like good numbers on a cold engine to me considering you prolly don't have a check valve to hold the pressure in the gauge.

I think you have a bad nozzle or nozzle spring. swap in a new injector and go.

Diesel Rod