Knocking and white smoke

[jesse_h]

I was driving about 70 on interstate when I started hearing a low ticking, thought it was just something rattling in the firewall area. About 5 miles later a really loud knocking started. I immediately left off and coasted to stop, watching the gauges. Everything was normal. Got out and checked under hood, knocking was very loud and seemed like in top end of engine. Got it back home here and started looking around. Won't knock while cold but runs horrible and constant white smoke. Dropped FASS filters, replaced, and primed. Pulled valved cover and visually checked valve train, nothing. Disconnected each injector solenoid wires and checked injectors, all right at .5 ohms. Unplugged harnesses at rocker cover and checked to solenoid, all were fine. Individually pulled wires off each solenoid, one at a time, started to check each one (manual injector kill test), and no difference from any of them. Ideas? I do have a FASS titanium 95 and DPP +50 injectors. Could my FASS just be putting out low psi? I do show code P0628 but was assuming it was because I have the FASS installed and not factory lift pump. Thanks in advance.
Jesse

2004.5 3500 NV5600

 

[AH64ID]

Any blow by? You can open the oil cap and set it in the opening to see if you’re getting too much crankcase pressure.

Dads 06 knocked like crazy when he had rings fail.

 

[petersonj]

It is possible to have a fuel injector leaking a small amount of fuel into one cylinder. If this is the cause, the fuel injector will leak 100% of the time and when that cylinder piston comes up on the compression stroke, the collected fuel will ignite quite early (causing the knock) and white smoke is likely to follow from incomplete combustion.

You can buy an injector line block-off tool (about $25.00 or so) and use it to test one cylinder at a time while running the engine. If it is a leaking injector, the engine will run smoothly on five cylinders and miss on the blocked off cylinder, but you will have no knock and no smoke.

Hope this helps.

- John

 

[jesse_h]

Any blow by? You can open the oil cap and set it in the opening to see if you’re getting too much crankcase pressure.

Dads 06 knocked like crazy when he had rings fail.

I didnt check before i pulled the valve cover off. With it off I can see a little but I think that might be just the normal amount of vapor you see? I have thought about rings but would it only knock when warm? It isn't doing it now when cold.

thanks

 

[jesse_h]

It is possible to have a fuel injector leaking a small amount of fuel into one cylinder. If this is the cause, the fuel injector will leak 100% of the time and when that cylinder piston comes up on the compression stroke, the collected fuel will ignite quite early (causing the knock) and white smoke is likely to follow from incomplete combustion.

You can buy an injector line block-off tool (about $25.00 or so) and use it to test one cylinder at a time while running the engine. If it is a leaking injector, the engine will run smoothly on five cylinders and miss on the blocked off cylinder, but you will have no knock and no smoke.

Hope this helps.

- John

You have a good point. I guess just shutting off the electrical to the injector wouldn't show anything if it is leaking by? I will see if I can find that cap tool.
Thanks for the help.

 

[Tuesdak]

This truck needs to be parked till it's fixed to avoid further damage like melting the engine down. Hopefully the damage hasn't happened or doesn't require pulling the engine.

The smoke when cold and knock when hot has "uncontrolled" fuel written all over it. Either fuel from leaking injector or oil from other sources. This advanced timing fuel source can cause a pre-ignition condition that quickly ruins (break melt) pistons and can burn valves.

It's possible you have blown a head gasket as you didn't say what the smoke smelled like. Coolant is a special burn your eyes over raw diesel. What is the coolant level? Pressure test the cooling system and if it fails consider you may be filling a cylinder with coolant. Hydro-lock and or bent rods would be a concern.

I would pull the exhaust manifold and see what cylinder(s) are smoking white when running cold. (I would not warm the engine up anymore. You don't want the fuel to light off on a warm/hot engine causing further damage.) Then concentrate on the cylinders smoking white by:
Pulling injectors and sending them off to be tested.
Use a borescope dropped down the injector hole to look for piston/cylinder damage.
Run a compression test.

If nothing is found you at least know the suspect cylinder(s) to concentrate further on.

 

[Prairie Dog]

It was pretty common to have an injector line come loose and make noise.

 

[sag2]

When an injector sticks open and melts the piston they knock like crazy. Compression or leakdown test time.