I have been enjoying myself immensely roaring up and down my garden in a Benford dumper which I am using to muck away the footings for my new garage (ebay, £200).
However, yesterday it ground to a halt with all the symptoms of fuel starvation. This morning I took the diesel tank off and cleaned it out - found a little water and some fine rust, but not too bad - took the fuel filter off and cleaned it all out, blew through all the pipes, bled it up to the injector and fired it up. It took a while (hand cranking start!) but it finally fired. Only trouble is, there's now loads of black smoke and it's not its usual self, sluggish and unwilling to rev, won't idle.
I've checked the fuel system very carefully and I'm fairly confident there's no air leaks, and now I'm stuck for ideas.
What's causing all the black smoke? Why did it break down in the first place?
Any hints gratefully received.
WB
Edited by Webmaster on 16/02/2008 at 16:44
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Does it have an exhaust like a round tub with a ring of small holes? If so, a common problem with them is blockage of the spark arrester. There is a giant brillo-pad inside which plugs with soot.
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Yes it does! I'll have a look at it now, thank you
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Black smoke usually means not enough air to burn the diesel, so I'd check to see if there's a mice nest in the air intake....
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I've had the exhaust off, and you can blow down it quite easily and very little soot came out. I also took the head to spark arrestor pipe off, and that's not obstructed at all.
I evicted most of the woodlice and earwigs from the air cleaner when I first got the dumper and I've ordered a new filter, it doesn't make a lot of difference if the air cleaner is on or off so I don't think the intake side of things is the problem. (I only ran it for a few seconds with the air filter off).
The previous owner told me he had fitted a new fuel pump. It is almost as if the timing is out but I can't see any way of altering the timing.
Edited by wobblyboot on 16/02/2008 at 17:13
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From the symptoms you describe it sounds as if the fuel pump is stuck in cold-start overfuel mode. Get to the fuel pump and make sure that the fuel rack can move freely-especially as the previous owner has messed with the fuel pump.
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The rack moves freely both ways. I think the problem is something to do with the pump, but it is such a simple bit of kit I can't see what it could be. The only adjustment possible seems to be maximum revs. Which I haven't touched.
Looks like it's back to the wheel barrow
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Take the injector out, turn it round, and put the pipe back on, so it squirts into the air.
**Put a clear bottle over the injector, to stop the spray hitting your skin.**
Crank the engine over, bleeding fuel from the union. After bleeding fuel through, see what the injector spray pattern is like. My bet would be that you don't actually see a proper spray pattern at all, rather you see some fairly limpid jets, and lots of dribbling; and that the needle in the injector is stuck.
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It's called "hosing".Servicing the injector will cure it.
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My fumblings have led me to the injector, as suggested, and there's evidence of water presence in the return circuit so the injector is now coming out. It's been reluctant so far but I have a vast assortment of hammers...
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I've had the injector out, it wasn't pretty inside or out. It's been thoroughly cleaned, the needle slides easily now and doing the test NC describes gives a very pleasing misting with no dribbling.
Although it fires it won't keep running. The compression is no better or worse than it was prior to the breakdown so I'm reluctant to take the head off, as it looks like it's more than a five minute job apart from anything else.
With the rocker cover off both valve are opening and closing, there's a clearance on both tappets and the valves aren't sticking.
I shall now thrash it with a stick.
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Every dumper I've ever seen has smoked anyway!!!!
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