poor starting 90 - getting there

[Matt_H]

we seem to be getting a bit better at starting the 90 in cold weather or after a day of not running, so far

battery replaced - turned over much quicker and doesn't die after tryign to start on x'th  attempt

timing belt replaced - runs smoother as timing was out a bit

fuel lift pump replaced - once running no longer takes 30 seconds before throttle does anything at all.

Now when really cold, like minus 2 like it has been for the last few days first thing in the morning it takes between 2-5 goes to start, it turns and fires maybe a few revolutions then it dies.  Same again, when I first repalced the lift it was normally the second time, but now its 4th or 5th however the weather is much colder.  Should I be suspecting the glow plugs (which I normally fire up for 20 seconds or so (tdi converted from td so on manual key switch).

One other thing worth mentioning is that when the car is warm and switched off I can pump the handle a couple of times - it then goes floppy which I'm told is the normal pumped up symptoms, leave it 10 seconds and I can do at least one handle pump before it goes floppy again - also on release you can hear a faint sort of squeak like the pressure reducing in the system.

I've tried pumping the system before starting (both with fuel solenoid open and closed) neither seems to make a difference, is there anyway air can leak into the system and cause bubbles of air.  Once warm she runs perfectly and if I try again at lunch time or early evening again fine no problem... as she is my main form of transoprt I've not been able to try mid day without an early morning run.

This is driving me wild now so your help gratefully appreciated!

Matthew

[Hangover]

Maybe the water loss is connected to the poor starting.
Kev

[hobbit]

If you yank the glow plugs see if they are wet

[Matt_H]

If you yank the glow plugs see if they are wet

wet with what?

M

[hobbit]

If you are loosing a bit of coolant into one of the pots, this could cause poor starting, not very likely but worth a look when checking other things

[Matt_H]

how would i tell the coolant was leaking into one of the bores without major pulling apart of bits?

Matthew

[Matt_H]

well been having a bit more of a look over. the glowplugs seem to do nothing when connected directly to the battery.  but i also tried starting in the middle of the day and it was ropey, throttle didnt do anything for a good 15 seconds.

When I took the glow plugs out the back three were covered in oil, front one was dry.  Is this a clue?

Matthew

[hobbit]

The oily ones wont be working, otherwise the oil would be burned off

[drmike]

Isn't this engine a TDI? In which case I thought that glow plugs were pretty much optional for starting. Mine aren't connected and it seems fine starting even on cold days. Certainly wiring them only resulted in a flat battery.

I know you've tried tons of things but I thought that really it came down to two things when starting:

Compression
Fuel supply

Well three if we include a starter motor that works.

However, am I right that you've compression tested and it sounds like you've been through the fuel side as well. I can't rercall have you checked the cut off solenoid?

Also have you changed all the plumbing taking fuel from tank to pump? Is it feasible to lash up a take up into a jerry can so you KNOW that the take up is OK and the line to the pump is OK?

Is it possible to bypass the fuel filter in this case? I ask as I have no idea!

Mike

[Matt_H]

yes it' a tdi engine, some seem better at cold starting than others, although after testing the glow plugs, none of them seem to work at all!

Why would there be oil on three of them though? - I didn't think oul should be around that area as the piston rings should clear the oil away.. Anyway I've just done 120 miles, stopped and filled with petrol 1 mile away then drove home.  stopped when i got in then restarted and left idling for about a minute.  stopeed and checked one of the sus glow plugs - there was still oil on part of the shaft and the tip.  

The watery oil seems like it may be a red herring as I washed out the tubes  few weeks ago - I'm thinking I may have just left enough to make the oil go murkey in the breather system.  I replaced the pipe with another at Ians (the 120 mile trip) and checked that on my return, at the engine side there was a good coating of oil which was black at the other none except the tiniest amount of something which was either my imagination or water vapour.  

The expansion tank for the rad was at around 3/4 as opposed to 1/2 when cold so that seems to be ok (I did chuck in rad weld yesterday)

I haven't checked the diesel pipes although nothing apepars to be leaking, and as far as I can tell I should only be worried about the pipe from the pump to the filter and from the filter to the high pressure pump/distro.  

My only other thing I haven't really looked at on that side is the solenoid and return circuit in case the soleniod isn't sealing totally I'm guessing that diesel could run back to the tank and air get back up into the injector pipes.  What I don't know though is where the solenoid sits in the circuit, I'm guessing between the filter and the actual pump thing in the pump/fuel distro which could cause lack of fuel - I have however tried pumping the lift pump before starting and this doesn't seem to make any difference at all (both with solenoid open and closed)

So the solenoid will be next on the list (it obviously works at cutting enough diesel off to stall the engine when we switch off the ignition), but where is this oily stuff coming from on the glow plugs (it doesn't smell of diesel)?  I've not done a compression test - anyone got a tester nearby I could borrow please?   This is when I wish I hadn't sold the disco 200 tdi engine!

Thanks everyone
Matthew

[drmike]

I'm not sure which diesel pipes you refer to but shouldn't you be concerned about the pipes the tank side of the pump? They could suck air in but any pipe with the smallest leak is bad news isn't it?

What about the banjo unions at the injectors for the return? Are they sound as I understand they can come loose and also leak, they use copper spring valves don'y they?

I once had a cut off solenoid on a VW engine that was intermittent faulty causing very poor running. This isn't your problem but could it be stuck closed or gummed up when you try to start?

I have no idea how much they cost but it can't be much.

Mike

[Matt_H]

Thanks for the things to think of...I'm not sure about the tank side of the pump, my thinking is that the pump should seal against going back and the filter etc should hold enough fuel if pre pump had air leaks, not sure how valid that is though!

I did look at the returns but didn't specifically check them.

I think there is a leak somewhere, as well as lack of glow plugs causing the problem... but the baffling thing is where is the oil coming from on the injector shafts?

I've checked the proper manual but it doesn't have a layout of the head so no idea if they get close to oil ways or not. :(

Thanks
Matthew

[hobbit]

I think Matt as already said, might be worth getting it compression tested

Would reveal at least if there is a prob there. What condition are the valve stem seals?

[Matt_H]

no idea about vlave stem seals - takign engines apart isn't really my area... I'll do it with help but I've never done a landy one and these thigns normally turn into "I wish I hadn't started this one"

Well this morning was warm enough not to need heat... She started first time, but I had to give her a bit of throttle, as soon as I came off the thottle she went very lumpy then wouldn't respond for about 20 seconds.

Now we know the glow plugs aren't working, tick over is probably too low which is not helping... I guess stem seals would explain oil - but why is it not being burnt off?!  Hmm

Oh well time to stop thinking and make my way home from work.

Matthew

[hobbit]

If you have the rocker cover off, they fit on top of the cylinderhead round the valves and seal the oil from getting down the shaft into the pots, look through the valve springs, and see if there are any caps on the valves, give them a poke with a small screwdriver and see if they are soft rubber or hard

[drmike]

Just a thought but you said it started and then ran lumpy for 20 seconds? Isn't that the time the glow plugs are timed to stay on?

Could it be that the glow plug circuit is upsetting something else electrical. As I recall the circuit around that bit is quite complicated.

One for those who know better: Is it possible just to pull out the connector that goes into the glow plug timer relay? Would that mean the plugs took no power?

Mike

[Matt_H]

ta kev..... I'll hand you a screw driver on saturday then!

Amazingly she started fine now the weather is better, really hop combination of glow plugs and too low tickover... we'll see

Has anyone got a pic of the fuel hi-pressure pump and which bits to twiddle which way... I do want to tweak boost and fuelign but wont touch that until I know everything else is ok.


Matthew

[Matt_H]

glow plugs aren't on a timer, its a simple switch on the ignition key on early models, after starting it drops back to the ignition 'slot' before ie. 1 = aux, 2= run and aux, 3= glow plugs only, 4=start, after starting it drops back to poss 3

Matthew