300Tdi cold start problem - and I've tried everything

[Ralph Hardwick]

Hi all

As the title says I have a cold start problem.

The engine will turn and turn and turn until the battery is nearly flat and then it will eventually fire.  I need to have the throttle flat to the floor or it won't go at all.

Once running, it goes fine and starts straight away the 2nd, 3rd and subsequent times.  If I leave it overnight it's back to square one.

I have spent weeks googling and reading every forum under the sun to get an answer and this is my list so far:

It's not the lift pump as this is brand new.

It's not the sedimenter as I have a 2 tank vegoil kit fitted and the diesel is drawn from a tank in the boot thereby bypassing the sedimenter.

As a result of having the veg kit fitted I have some 'windows' in the fuel line upstream of the fuel fliter.  These show no air bibbles and are permanently 'primed'  o there are no air leaks in the delivery system allowing fuel to drain back.

I have replaced the entire 'spill pipe' setup with a new part and all new copper washers so I am convinced there is no leak here.

I have replaced the fuel stop solenoid with a new one.

Having spent and hour and a half ripping the dashboard out I can confirm that it isn't the 'spider' unit.  As there isn't one fitted :roll:

I have removed an injector pipe and when cranking I get fuel (although not a lot I must admit)

I have replaced and primed the fuel filter.

Tomorrow I shall try and run a new earth from the engine although I'm not holding my breath that this will make any difference.

I also intend to take the car for a run with REDEX advanced in the fuel just to clean out the insides.

I have a dual battery setup with an optima red top starter which gives 14+volts.  Unfortunatly my arms aren't long enough to see what this drops to when cranking.  But I have 'jumped' the solenoid directly from the second battery (when testing for the spider) with no great benefit.

So hopefully you can see I have tried most things.  my worry is that the injection pump is faulty although it runs fine once started.

Does anyone have any other ideas?  Are there any settings on the pump which may have gone 'off-tune'?

It's a non-EDC 95 auto model.

Any help would be gratefully recieved as I don't have a lot of hair left to pull out anymore. :'(

[J B]

it wont start cold on veg oil, it needs to heated or started on diesel then switch to veg

you can get fuel heaters that have a couple of glow plugs in-line for cold start, then the engine coolant takes over

i'll try and find a link for it

[J B]

looky here

http://www.vow2.co.uk/Vow2D.htm

[Ralph Hardwick]

Thanks for the reply.  I obviously didn't explain very well.

The car has a 2 tank veg oil system which means it starts on diesel. I then manually chang-over when it's up to temperature.

I only ever start on pure diesel :D

[trecfive]

Has this started since it was converted to run on veg oil/diesel.

[Ralph Hardwick]

The car started to play up before the conversion but this was because of a faulty lift pump.

This was over a year ago.  I put the car in the garage and over the last year I have revamped alsorts including fitting the veg kit and the new lift pump.

However I did used to run the car on a 70/30 diesel/veg mix before.

[J B]

only one thing springs to mind then, do you switch back to diesel for a few minutes before turning the engine off at the end of the day

otherwise the fuel pumps still full of veg when you try and start it in the morning

[trecfive]

As above, my thoughts

[bilge rat]

i'll 3rd above and also what make of lift pump did you replace it with . i have heard of people replacing them with a certain brand and finding them no good neither ..alan

[Ralph Hardwick]

the car is only running on diesel at the moment.

I have only recently fitted the veg kit and I have only tried it once and it was fully purged before switching off.

It definately isn't a veg oil related problem as all the pipes are primed with diesel.

The lift pump was from paddocks I think it was an 'allmakes'

[JIMBOBLY]

just a thought,it isnt a tiny little diaphram in the sender in the tank,ive know it before on other vechiles :-k

[Ralph Hardwick]

just a thought,it isnt a tiny little diaphram in the sender in the tank,ive know it before on other vechiles :-k

Can you be a little more specific? :)

[RichardM]

I'd try the new earth to the engine...or try what I do...three goes on the glow plugs then it starts immediately.  I know people say you don't need them, but when its cold mine takes ages to start, unless I give it three goes on the glow plugs.  Mines a non-EDC auto as well, not that it should make a difference.

[Ralph Hardwick]

Thanks for that.

I do tend to give it at least a couple of goes with the glow plugs before i try and crank it.

I can't help thinking it's a fuel problem :'(

[RichardM]

I do tend to give it at least a couple of goes with the glow plugs before i try and crank it.

Try three or four goes, just to please me  :lol:
I thought mine was a fuel problem, same symptoms as you....

[Ralph Hardwick]

Try three or four goes, just to please me  :lol:
I thought mine was a fuel problem, same symptoms as you....

I'll give it a try and let you know.

mine is doing the same and it was running so slow but now i have turned the pump up a bit and will see if it has worked the screw you need to turn is on the injection pump the air mix screw you will need to take the tamper prove cap off and a clip from the bolt and undo the 13mm nut put a screw driver in the end to hold the screw and once undone turn it clock wise the engine revs will increase i will let you know if it has sorted mine out

I'll look forward to hearing your results.  thanks

[JIMBOBLY]

i mean the sender unit in the tank,there are little diaphrams in there,you cant replace them,you would have to have the whole lot,but when one of them gets a tiny hole in them,it will let the diesel drain back a little,but not completely because you still have diesel in the pipe,but then you have an air gap,causing the problem you have :-k

[Ralph Hardwick]

Jim
Thanks for the info.  I'm pretty certain it's not draining back as the fuel filiter and pipes are all still full before I start.

Cheers

[Ralph Hardwick]

Hopefully I have a solution.
As you suggested I adjusted the power screw on the side of the pump and the car started almost imediatly
Unfortunatly I 'lost' the original settings when I removed the 'anti-tamper' device.
So it's been reset with a bit of guess work but it seems to be okay.  Apparently I need to worry about the exhaust gas temperature but I will continue to 'tweak' until it feels right.
Thanks for all the comments