Bongo Fury

What could be going on? From cold, Freda starts but in an unwilling, chuggy, spluttering sort of way throwing out loads of blue smoke (I run on bio-fuel; 100% vegetable oil with no mineral oil content). Tickle the throttle up to no more than 1,000 rpm (higher revs make it worse) for only about 10-15 seconds and she'll settle down and idle as nomal. After this little performance, she'll run fine and goes like a train. I've been doing a good bit of motorway driving lately and she's happiest at 70-80 (m'lud!) so no worries on that score. Starts ok from warm. Any ideas, anyone? Could it be glow plugs?

From my little knowledge

I would check filters main and banjo and the glow plugs

Are you getting voltage at the glowplugs? Bit confused what fuel you are runnning, is it proper bio diesel or is it neat veg oil? Are the cold start solenoids working (Do the revs start off a bit hihger than normal tick over, drop a bit @20 degrees then drop to normal revs at @55 degrees? if you switch on the ac once the engines warmed up, do the engine revs rise slightly?)
May be more useful to alter the topic to something relevant to iffy starting rather than "err...dunno" more chance of getting useful answers

Sounds like it might be poor quality biofuel, which is thicker than diesel when cold.
I've had similar problems when running on cooking oil and forgetting to top up with diesel at the end of my trip Smoke should be white though, as blue is burning oil

Dear Miss Fixit. Apologies for the vague title. Nevertheless, it worked as I rather hoped you would reply in your capacity as queen of the diesel engine. ersonally I prefer a big petrol V8 and believe that diesels belong in tractors). Consequently I don't know that much about diesels.

Am I getting voltage at the glowplugs? Don't know, but the warning light comes on when I turn the key and goes out with a "click" so I think something is happening. I don't own a volt meter, unfortunately.

The supplier tells me that the fuel I use is a mix of rapeseed and soya oils with some additives, then the glycerol removed. There is no mineral diesel oil content, so I guess it is neat veg oil. What is "proper" bio-diesel?

Not sure what cold start solenoids are but, yes, the revs drop away to idle at about 700rpm when she warms up.

There is a very slight rise in the rpm when the air con is switched on.

She was serviced by a Bongo-competent garage on the 29th June when all the filters were changed.

Hope this helps in your diagnosis, but any more quetions, please fire away.

Dave

Dear Franco. I did wonder about the quality of the fuel and took it up with the supplier. I did have a duff batch beforen the last service which required me to drain some out via the little white plug on the oil filter. That had a black sediment in it which he told me was glycerol left in after inadequate filtering at manufacture. The smoke I referred to is, more accurately, a pale greyish blue. It's not burning engine oil - the rings and compression levels are good.

pistonbroke wrote:Dear Franco. I did wonder about the quality of the fuel and took it up with the supplier. I did have a duff batch beforen the last service which required me to drain some out via the little white plug on the oil filter. That had a black sediment in it which he told me was glycerol left in after inadequate filtering at manufacture. The smoke I referred to is, more accurately, a pale greyish blue. It's not burning engine oil - the rings and compression levels are good.

I didn't think you could filter the glycerol out - isn't that what they use the caustic soda and methanol for? Try putting some diesel in and see if that works. I used to run a 50/50 mix of cooking oil and diesel for general running and that caused your symptoms on a colder mornings - leave it to tick-over for a couple of minutes and all was fine

Dear John. I used to run up to 50/50 diesel/veg oil in summer and down to 70/30 or even 80/20 in the cold weather and yes, it could start a bit lumpy if the ratios were wrong for the temperature as the veg oil began to gel. The stuff I use at the moment is ok down to -10 degrees and can be mixed with diesel if things get colder than that. It's also delivered, so no queueing at the petrol station and its less of a faff, having to estimate what's left in the tank and how much of which to put in to keep the ratios right. I do mix diesel with it when I'm in an area where the bio isn't available and it makes no difference. Not sure about the technicalities of the filtering process and the additives.

I'd agree with Franco on this, especially if you say you had a duff batch fairly recently, did you empty & flush the fuel tank to remove it all? Sounds like maybe your biodiesel suppliers aren't processing it properly? no expert on the process personally, but straight veg oil is not the same as properly processed bio diesel, the latter should be able to be used as a substitute for derv. Veg oil should either be mixed with diesel, or used in such a way that you start & flush out before stopping with diesel.
I've recently had similar symptoms as yours after a period of using @50% sunflower oil, just filled up with diesel, no starting issues at all now.
If it's not that, did it start since the service? ie something they did, such as not tighten the fuel filter properly? (not likely from the symptoms though)

May also be worth checking to see if your fuel pump seals are leaking at all, have a feel underneath it.

Thanks both for your advice. I'll run it just on diesel for 3 or 4 tankfuls to see if that clears it. I guess that would be enough to flush out any impurities. Shame, because it runs really well on the bio and is 'greener' than diesel.

If you run it right down, I reckon you'll notice the difference on the first diesel fill up, maybe try a mix from that point forward if it cures the issue? Or go & have a chat with the supplier (or trading standards) again if he's supplying biofuel not fit for purpose?

missfixit70 wrote:If you run it right down, I reckon you'll notice the difference on the first diesel fill up, maybe try a mix from that point forward if it cures the issue? Or go & have a chat with the supplier (or trading standards) again if he's supplying biofuel not fit for purpose?

If the product has not been endorsed by the manufacturer IE Mazda,the Trading Standards will not persue the issue.The retailer should display this fact on the EMC/Dispenser.

Cheers

I've been using this guy's bio for at least 9 months now, even through last winter (with about 70% diesel mixed in) and varying the ratio of bio to diesel as the weather improves and the temperature rises. It's only recently that problems have occured (I've had to drain the fuel filter a couple of times which only takes 5 minutes) which suggests to me that his filtering process has suffered as his business has grown and he tries to meet demand. It's an annoying faff at start up. Once she's settled down, Freda flies along.

I'm watching this with interest as mine has the same symptoms but I run on mostly Shell V-Power diesel.

My local spanner monkey has tested glow plugs & feed and all seems well but thinks worn injectors or a tired fuel pump may be the cause.


Keep posting . . . .