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Diesel engine has multiple explosions in exhaust when starting questions

kshansen

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Mar 11, 2012
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I am wondering if it could be too much fuel conditioner in the fuel. I am using a brand called PenRay PowerPlus. I got a deal on it that I couldn't turn down. In cold temperatures it comes out of the bottle with the pouring consistency of syrup. I thought that was weird. I always used the 911 brand before and it has the same consistency as the fuel does, at any temperature.

That does sound strange, the thick conditioner, is it blended in before fuel is put on tank?

I tried to look for information on the conditioner but there seem to be at least a couple different types with the Power Plus name. Do you have the part number off a bottle handy to check on the MSDS. It will give you a basic description of the chemical make-up. At least one I looked at was mostly kerosene so I don't see why it would be thick like syrup.

Go to: http://penray.com/products/winter-pow-r-plus-diesel-fuel-treatment/

Over on the left side there is in the blue box a MSDS selection click on that and with your info off the bottle do a search to see what is in it.

On the other side of the problem I'd like to pull the valve cover off and check valve action while cold. If a valve or two is sticking you should be able to see it even without using a feeler gauge. Best if you could turn the engine over slow by hand.
 
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oarwhat

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buffalo,n.y.
After reading this " It sounds as if there is only one strong cylinder firing when it starts in sub-freezing temperatures. The exhaust popping doesn't start unless I increase the throttle to about 1000 RPMs or more." You are just pushing the engine to hard before it warms up. That's it IMO
 

Tinkerer

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After reading this " It sounds as if there is only one strong cylinder firing when it starts in sub-freezing temperatures. The exhaust popping doesn't start unless I increase the throttle to about 1000 RPMs or more." You are just pushing the engine to hard before it warms up. That's it IMO
I wish it were that simple oarwhat. But the factory spec. idle speed is 750 RPMs. 1500 or more would be pushing it a little hard on a cold start. Installing the electric coolant heater that I mentioned earlier in the thread will eliminate the problem. But, I would still like to determine (and I will) what causes it.
 
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old-iron-habit

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If it is not firing clean on all cylinders when you first start it, there will be unburnt fuel from the non firing cylinders being pushed into the exhaust manifold and stack. In all probability when the weaker cylinders start firing when you increase the RPM's, it is pushing partially burnt fuel due to incomplete combustion into the exhaust igniting the fuel already there. I have an old 4-71 Detroit with a ton of hours on it, that has been doing this in the winter for many years. It always farts, pops, and barks put of the exhaust when the last cylinder kicks in. It sounds like opening day of duck hunting for a few seconds.
 

Delmer

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I doubt the fuel igniting in the exhaust, but it sounds like the combustion is just taking so long (getting a late start and missing peak compression) that it's just getting going and the exhaust valve opens already, the ether helping is the best clue. Maybe bump up the timing a bit? add some cetane boost?

Or the valves are sticking slightly but I can't see that "exploding" into the exhaust?
 

Tinkerer

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Not yet Bill. It may not be a problem now. The engine has a factory installed freeze plug style block heater in it. It is located behind the air intake manifold. The electric cord that came with it is not hard wired to it. It has a right angle plug right on the heater. There is a threaded stud on the heater that is supposed to have a washer and nut that is a safety to keep it from getting unplugged. Those two little gems were missing and the cord was sitting there unhooked. I had been plugging an extension cord onto the other end of the cord when it was below freezing like I normally do. I never gave a thought to the fact that the block heater wasn't working. DUH !! When it gets warmer out I have to have the radiator repaired, and when I do that I am going remove the fuel injectors and take them to a professional fuel injection repair shop and have them pop tested. I have a suspicion about them not being quite right.
 

Tinkerer

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Nice find Mobiltech. No mine doesn't like the one in the video. That person starting the dozer would never be allowed near it, if it were mine. That is perfect example of not using the glow plugs long enough and having the throttle open too far. My engine sounded like gunshots in the exhaust, not like someone were inside the dozer engine's combustion chamber with a sledge hammer.
 
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frogfarmer

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Aug 25, 2010
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234
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South East Missouri
Delmer wrote: I doubt the fuel igniting in the exhaust, but it sounds like the combustion is just taking so long (getting a late start and missing peak compression) that it's just getting going and the exhaust valve opens already, the ether helping is the best clue. Maybe bump up the timing a bit?

Pump timing could be part of the issue but if that is the case it needs to be retarded instead of advanced. Advancing the timing even a degree past the sweet spot can cause starting issues but no run issues. Advanced timing on a warm engine normally makes more power.
 
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