A word of warning on Biodiesel and help please

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XantiaMan
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A word of warning on Biodiesel and help please

Post by XantiaMan »

This afternoon i decided to take a trek to north london to visit pure fuels, and bought 30 quids worth of B100, having used up to 90% rapeseed SVO/10% diesel i expected no problems however a progressive loss of power, then a massive flat spot followed by the engine management light flashing on meant there was a problem.

Upon removing the fuel filter there wasnt that much dirt in it, definatly not clogged, the bottom of the filter was a different story i spent ages getting all the flakes of crap out and eventually used compressed air on the housing till it was bone dry and free of dirt.

Refitted a a new fuel filter, primed the system, but no matter what i do, i cannot properly bleed the system out, i can see tiny bubbles of air in the pipe going to the fuel pump, i can press the priming bulb and watch them go, but it still comes back again.

Does anyone have any advice they can lend me, all my performance has gone, it barely gets up hills at the moment. I expected a cleaning side effect but not to this extent.

Gareth

elma
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Post by elma »

If your fuel filters a state maybe so is the gauze on the pick up.
Get under the o/s rear seat (in the car) you might need to take out the seat to peel back the carpet, but I didn't.
Theres a round black rubber cover, take it off.
You will find a circular thing with two pipes going to it.
Try to unscrew it by hand, if you cant use a large flat screwdriver and a hammer to gently get it moving.
You'll probably have to disconnect the 2 pipes at this point.
Lift the whole thing out and check if the gauze at the bottom of the pick up is clean.

elma
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Post by elma »

Also how are you trying to prime the system?
If the car won't start at all then you may have a nice air lock.
You need to slacken off the injector pipes from the injectors, not the pump end. And don't undo the injectors themselves, that would be rather dangerous.
Turn over the car and tighten the pipes one at a time starting from the n/s and moving towards the o/s 1 injector pipe at a time.

It will play a nice tune as it starts up.

XantiaMan
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Post by XantiaMan »

Well i managed to drive it 85 miles home tonight but with very flat performance so its not an airlock, just air in the system. I am using the priming bulb to prime but there is no bleed screw on the fuel pump.

elma
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Post by elma »

I reckon the pickup gauze is clogged then, it kills performance.
Do a search theres a few threads on it.

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DickieG
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Post by DickieG »

I agree with Elma on this Gareth, I have a photo I took of a blocked fuel pickup from Xantia that suffered fuel starvation problems due to a horrible brown slime covering the gauze. PM me your email and I'll forward it to you and you'll see what I mean. Simple to cure as mentioned, have a couple of new jubilee clips to re-seal the pipes. Cleaning it was a simple as cleaning can be.

elma
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Post by elma »

DickieG wrote:have a couple of new jubilee clips to re-seal the pipes.
Thats very important, should've mentioned it. Sorry.

XantiaMan
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Post by XantiaMan »

Ok guys thanks for the advice, Richard i'll drop you a mail :)

elma
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Post by elma »

If its not that then I would suggest that the biodiesel you bought is rather rubbish.
Good luck.

XantiaMan
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Post by XantiaMan »

I'll hold judgement until all the air has gone out of the system, but upon removing the fuel pick-up/sender unit i was greeted with this -

Image

Image

So, the pick up was definatly blocked. Never seen anything like it! It's amazing the car ran at all.

There is still some air present in the system, is it best to bleed it with engine running or off?

Gareth

elma
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Post by elma »

elma wrote:Also how are you trying to prime the system?
If the car won't start at all then you may have a nice air lock.
You need to slacken off the injector pipes from the injectors, not the pump end. And don't undo the injectors themselves, that would be rather dangerous.
Turn over the car and tighten the pipes one at a time starting from the n/s and moving towards the o/s 1 injector pipe at a time.

It will play a nice tune as it starts up.
This is the only way I have ever known to get air out of diesel.
If theres more getting in I reckon you have a pipe or joint not sealing.
Although wait til you run out of biodiesel and fill up with something else before passing judgement. That stuff has a reputation for frothing up quite a lot, it might just be doing that when its sucked up.

I've never seen a guaze filter as clogged as yours, as you said I'm amazed it ran. You must have had some prity manky fuel in your car at some point.

XantiaMan
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Post by XantiaMan »

elma wrote:
elma wrote:Also how are you trying to prime the system?
If the car won't start at all then you may have a nice air lock.
You need to slacken off the injector pipes from the injectors, not the pump end. And don't undo the injectors themselves, that would be rather dangerous.
Turn over the car and tighten the pipes one at a time starting from the n/s and moving towards the o/s 1 injector pipe at a time.

It will play a nice tune as it starts up.
This is the only way I have ever known to get air out of diesel.
If theres more getting in I reckon you have a pipe or joint not sealing.
Although wait til you run out of biodiesel and fill up with something else before passing judgement. That stuff has a reputation for frothing up quite a lot, it might just be doing that when its sucked up.

I've never seen a guaze filter as clogged as yours, as you said I'm amazed it ran. You must have had some prity manky fuel in your car at some point.
Yeah it was pretty bad. Not sure why it was so bad though, only 2 previous owners. The pipes had obviously been off before as neither of the jubilee clips matched.

Car ran perfect previous to the s**t in the tank so i dont suspect a leak anywhere else and will persevere with bleeding it.

I wont be using biodiesel again though, it was just a trial but didnt want this much hassle, it also stinks really bad, far worse than rapeseed SVO which i can cope with.

elma
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Post by elma »

As I mentioned before, biodiesel froths terribly.
London cabbies won't use it as you can only half fill the tank at the pump and then the froth comes to the top.
Wait til you're back on diesel/veg before you try anything as you may be wasting you're time.
First place I'd look if it remains though is the filter housing. These let air in anyway on a lot of cars and you've just cleaned yours. Maybe some of the dirt was forming a seal.

XantiaMan
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Post by XantiaMan »

Ok problem solved, it pays not to overlook anything!

Just as i was about to undo the filter top, there was my problem (50% of it), the boost compensator hose was completely torn off, so no extra fuel on boost, cut it down one last time as a temporary measure till i get another bit, and its 100% back to normal!

So phew, there is nothing worse than chasing after a problem, also thanks for you elma and DickieG for suggesting to check the fuel pick up, again why it ran at all i will never know BUT it definatly needed doing and i will be checking it again in another 500 miles once i've got rid of all the biodiesel.

Gareth

caveman_si
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Post by caveman_si »

So you've been running SVo and you stick some biodiesel in with out researching the possible outcomes????

The flakes in the bottom of the fuel filter can be there regardless of what fuel you run on. Ive seen it on vehicles that have never run on anything other then "proper diesel".

Biodiesel has cleaning properties so you should expect the gunk in your tank to get cleaned out.

What I would hazzard a guess at has happend is the SVO in your tank has reacted with the biodiesel and clogged up the fuel tank filter. Thats why its recommened not to mix SVO and biodiesel of unknown origin in your fuel tank. Not a reason to stop using it.