What in the World?

[pastorjeep]

My truck started smoking white (unburned fuel?) and missing, So I used my had to rev the throttle under the hood while watching the exhaust to see if it would clear with a little rpm. I was probably at about 2000 rpm and heard a pop and then a loud bop, bop, bop, coming from the intake with each revolution. Intake valve was my first thought? What kind of damage would a leaking injector do that would cause a back firing through the intake? Trying to decide where to start.

 

[cpdenton]

Pull the valve cover. See what broke.

Not sure what kind of smoke would have caused this damage, but the missing and white smoke is very much like symptoms I had when I had water in my fuel.

 

[pastorjeep]

I just installed an electric pump and I thought maybe it was advancing the IP to much, but when I put a gauge on it it was saying 5-7 psi at the filter. So as I was letting it run trying to see if it would clear up something let go.

 

[theshyguy]

Unburnt diesel will be black. Is the smoke for sure white or a blue tint to it? Smell sweet or burn your eyes?

 

[pastorjeep]

Black smoke is overfueling, where white (smells like raw diesel) smoke is just completely unburnt fuel, like a dead cylinder.

 

[shawn deere]

Maybe a valve stuck open causing no compression, then dropped....

 

[Macrobb]

Chances are you'll find either a bent pushrod or loose rocker. Probably not a bent/broken valve. I suppose you *could* have a dropped valve/broken valve spring, but it's pretty rare.

Remember, the valve to piston clearance is like .030" at one point in the cycle. If a lifter sticks and 'pumps up', the piston can easily whack the valve. The valve is square to the piston, though, so what'll happen is it will bend the pushrod, which is the 'weakest link'.

 

[icanfixall]

Am so looking forwards to read what the cause was. Way too many variables to venture a guess.

 

[pastorjeep]

Hope to pull it apart this week with some warmer weather coming. I don't want to start it again...but...I was thinking of starting it letting it idle while cracking injectors to locate which cylinder dropped. What do you guys think?

 

[icanfixall]

I would not start this engine but I would pull valve covers. Maybe hand crank the engine thru a complete revolution. That can tell you most anything you need to know. If a piece of a valve dropped please remember the clearance between the head and top of the piston is around 40 thousands.. Not enough clearance for a piece of a valve.

 

[Hydro-idi]

^^^Agreed. Starting it might turn your engine into a 1K boat anchor depending on what's wrong with it. Too risky.

 

[Macrobb]

Just pull the valve covers. It's not that big a deal, really!
The only pain point is the fuel filter which will have to be removed I believe.

 

[shawn deere]

Just pull the valve covers. It's not that big a deal, really!
The only pain point is the fuel filter which will have to be removed I believe.

And the HVAC. Passenger side kinda sucks. Lol

 

[Macrobb]

And the HVAC. Passenger side kinda sucks. Lol

On my 88 with AC, I've been able to get it off without messing with the HVAC box at all. It's a bit of a wiggle-tug-wiggle deal, but it comes out and goes back on.

 

[shawn deere]

Indeed. A spare 1/16th of room would be nice tho