Sorry, non BX Bosch Diesel Pump Question

Post by **mat_fenwick** » Fri Jun 27, 2008 9:57 pm

I have a VW LT35 diesel van, with a Bosch diesel pump. It has been stood for about 8 months and now won't start.

There is no fuel getting to the injectors, the solenoid is about 12 months old and I have removed the plunger to prove that isn't the problem.
There is a clear pipe from the fuel filter and when I cranked the engine I could not see fuel being lifter by the pump. I have filled the fuel filter with fresh diesel, and ONLY then can I see fuel being drawn up by the pump. After a few seconds, no more fuel is drawn through.

However, there is still no fuel reaching the injectors. My question is, can anyone think of another possible cause of the problem, apart from the pump?

DavidRutherford · Post by **DavidRutherford** » Fri Jun 27, 2008 10:05 pm

A few things spring to mind.

The first one is the very real possibility that you have diesel fungus in your tank. It's a very odd bacterial growth that forms on the line between water and diesel, and grows into a gooey black yeuch. There is a biocide that can be added to the tank to kill it off and turn it all back into diesel fuel.

Put a long length of clear hose on the feed pipe up from the tank. Can you suck diesel out of the tank yourself?

Alternatively, it may be that the vanes in the injection pump have jammed up. Rare, but I have had it happen. If so, run the engine from a jerry-can of fuel placed higher than the injection pump for a while (until its hot) and tap the pump a couple of times. Now see if it will draw fuel from the tank.

Alternatively, it's not just a completely blocked filter is it?

Post by **mat_fenwick** » Fri Jun 27, 2008 10:43 pm

Hi David,

Thanks for the ideas. I am pretty sure it's not the filter - I change it every 10k, and it's only done 2k since the last change. Having said that, I couldn't get hold of a genuine one last time so put on a cheapy.
I will try the gravity feed fuel system - if I can at least get the engine to run that will at least prove the high pressure side of the pump, and if it still doesn't start I know the problem lies with the pump somewhere.

demag · Post by **demag** » Fri Jun 27, 2008 11:23 pm

It's amazing the amount of vehicles that get laid up for a while then won't start after. I'm assuming it was running ok before? In which case surely it has to be fuel related if nothing else has changed. Old fuel waxed and bunged pipework up? Are the injector pipes clear? I will be surprised if its a pump failure.

MULLEY · Post by **MULLEY** » Fri Jun 27, 2008 11:30 pm

Might be as simple as the fuel having gone off.

I'd syphon it out & put some fresh diesel in & try firing her up again. If that does work, see if you can get the old fuel tested & whether it will be ok to mix it with the new stuff or not....

DavidRutherford · Post by **DavidRutherford** » Fri Jun 27, 2008 11:52 pm

MULLEY · Post by **MULLEY** » Sat Jun 28, 2008 12:23 am

Yup, you are being a bore & a pain. I'm getting tired of your endless criticisms of others, or is that your sense of humour?? If Matt wanted to mention it fair enough its his post not yours.

I suggest you set up your own site & then when you are in charge you can revoke access as you see fit.

If you get so wound up by this, dont use this forum.

Vanny · Post by **Vanny** » Sat Jun 28, 2008 1:37 am

you'll find he already has a site of his own!

god knows what the missing post was, but diesel doesnt go off the way petrol used to. I've had disel sat about in jerry cans thats been fie many years later (once i got desperate enough to use it), certainly not the same with petrol though. Do you have any actual experience with fuel going off mulley?

stuart_hedges · Post by **stuart_hedges** » Sat Jun 28, 2008 1:41 am

Um, I've clearly missed something here. I don't often post in here because I don't know much about technical stuff but I know for a fact that David does. Did he boringly and painfully say something that happens to be true?

I am confused... the only thing I can think of is that I've experienced petrol going off, but not diesel. Was that it? Admittedly I've never owned a diesel car that had been standing, so I didn't post... <shrugs>

Post by **docchevron** » Sat Jun 28, 2008 2:38 am

MULLEY wrote:Yup, you are being a bore & a pain. I'm getting tired of your endless criticisms of others, or is that your sense of humour?? If Matt wanted to mention it fair enough its his post not yours.

I suggest you set up your own site & then when you are in charge you can revoke access as you see fit.

If you get so wound up by this, dont use this forum.

Bloody hell Mulley, run out of chill pills?

I'm going ot guess that Daivid drew mention to your previous post thus:

Mulley wrote:Might be as simple as the fuel having gone off.

I'd syphon it out & put some fresh diesel in & try firing her up again. If that does work, see if you can get the old fuel tested & whether it will be ok to mix it with the new stuff or not....

First, diesel doesn't "go off".
Second, get the fuel tested for what? STD's?? IQ levels? Ability in freehand artistic endevours?

Third, in Mats post he said this:

Mat Fenwick wrote:There is no fuel getting to the injectors

So even assuming that the fuel "had gone off" which if course it can't actually do, that wouldn't explain why it was failing to reach the injectors, given that even even shite old fuel would reach the injectors, even if it wouldn't burn, which of course it actually would.

So, if fresh shiny fuel in the filter will draw but then stops, it would rather suggest a blockage in the drawn (Vacuum) side of the fuel system.

I have no idea what Davids post said, but I'll guess it pointed out that just emptying the old fuel and refilling with fresh to cure the problem carries the same odds as winning the lottery every week for the next 500 years?!

mountainmanUK · Post by **mountainmanUK** » Sat Jun 28, 2008 8:57 am

I must have been one of the few that DID see David's pre-edited post.

If it helps anyone to further assist the poster of the original poster (Matt), I will re-quote the important part of Matt's first post, which David had quoted in his response.....

There is no fuel getting to the injectors,

As for the further "negative development" of this thread, I am in total agreement with Stu's thinking........this is a Technical Forum, and I will generally only post in here something of which I have personal experience or knowledge, things that I am sure David R possessses vast quantities of!

Whilst it can seem to be helpful to respond to a "cry for help" with any suggestions that come to mind......it is generally advisable to at least read through the original problem (and any responses so far), to ensure that the original problem is correctly understood.

Once again.......I think the PM system is ideal for any "personal arguments" etc........NOT a technical thread.
Matt doesn't need to see bickering....he wants to get his f*^%^ng diesel running!!

Just MHO, as always

Dave

DavidRutherford · Post by **DavidRutherford** » Sat Jun 28, 2008 9:39 am

For those who didn't see it, my post did indeed highlight exactly what's already been said:

Diesel doesn't go off, and Matt has already catagorically stated that there's no fuel getting to the injectors, be it fresh or otherwise.

And I apologied for being a bore and a pain for highlighting people not reading and understanding the problem being discussed before blurting out a diagnosis which is completely impossible.

Making guesses like that are at best a waste of time, and at worst could have someone spending a lot of time and money chasing a red-herring.

AndersDK · Post by **AndersDK** » Sat Jun 28, 2008 1:49 pm

May I moderately suggest that we end this thread here - and then start over in a new thread - exhibiting quite a bit more respect to each other.