300tdi bad starter

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pjcmossop

New Member
Posts
5
I recently bought a 96 model yr 300tdi 90. with 105k on the clock. It is a pig to start and always has been. Since i have owned it i have been through the entire fuel system, new filters, new lift pump, injector pump off and serviced, injectors tested, fuel lines tested for leaks and yet still starting problem persists. It is only the first start of the day when it needs a really good crank, thereafter, for the rest of the day it starts on first flick of the key but problem returns the next morning.

When running it is a bit flat at the bottom range but otherwise a very good runner with plenty of turbo boost. Timing belt has also bee replaced and timing is bang on.

Any thoughts?
 
You shouldn't need heater plugs in weather above about 5 degrees.

When you say its 'poor' at starting, how so?

Does it spin fast, or slowly at first?

When you turn the key, it should (at least mine does) really throw the engine round quite fast, mine is the fastest spinning diesel starter ive ever seen.

You say you've checked the whole fuel system, it is getting air in over night?
 
Thanks all,

Air getting in the system overnight was my initial thought but the whole system has been overhauled and there is no evidence of any leaks. I had though about setting up a gravity feed straight into the filter, leaving it overnight and seeing how it started the next morning just as a process of elimination. On the same vein, someone suggested fitting a non return valve somewhere in the system although I haven’t figured out the best place for one yet. If it starts ok with a gravity feed test I might do this as it would suggest fuel is running back overnight but on the basis all components on route have been replaced or serviced I would be surprised.

Starter is pretty strong and throws over pretty well. but I will check all the leads and earth strap is a good point. I had a 101 that was a rubbish starter and earth stap was the culprit.

Heater plugs have all been tested too and this problem was consistent through the summer as well so don't think it is them.

I am still leaning toward fuel as it is only the first start of the day when it is a problem.

Could it be a compression issue?
 
Thanks, but have tried that. Indeed pump has been off and overhauled professionally. Have even tried a pump off another wagon which has no probs and starting problem prevails so I have re fitted the original one and ruled out the injector pump as the source of the problem.

I am going to set up a gravity feed and check the earth strap. After that I have run out of ideas.

Any other thoughts welcome.
 
Still rekon its getting air in. Mine is missing a copper washer, so it gets a bit of air in overnight. In t'mornin you have to really crank it to make it fire, then its fine.

How were the lines checked for leaks? You may not notice one if its tiny, but it will still draw air in.
 
You shouldn't need heater plugs in weather above about 5 degrees.

When you say its 'poor' at starting, how so?

Does it spin fast, or slowly at first?

When you turn the key, it should (at least mine does) really throw the engine round quite fast, mine is the fastest spinning diesel starter ive ever seen.

You say you've checked the whole fuel system, it is getting air in over night?

Nah - 300tdi's are not great at starting even if its mild out - they need the glow plugs. Both the 90 and the Disco are the same and other 300tdi's I have driven.

I find that they need the basic glow session to get it to start reasonably quickly.

The 90 spins much faster than the Disco but it still takes just as long without the glows, the Disco seems really sluggish but with glows it starts every time. The 300's are like this, some spin fast some don't - but a little earth strap check would be good (take it off, file the contacts clean refit with some battery terminal goo or vaseline).

On the topic of these - if your ever having problems I suggest you buy a good set of glows (not those rubbish £2 something a piece ones on ebay in little blue boxes, utter rubbish the ceramic breaks and the terminal spins and breaks the feed wire and they burn up if you use them for more than 20seconds - rant over) - get bosch or even the Lucas ones are good.

pjcmossop: if your having problems at the moment then I suspect your either not getting the engine over fast enough (is it REALLY sluggish) or your compression is way low, but you don't mention it running badly otherwise or after the first start so. It could be the fuel shutoff is sticking but that would probably happen every time, so air does make sence, the fault would almost certainly have to be near the pump, on the feed down to it, as these pumps can handle a bit of air (they self bleed - there is no automatic air bleeder anywhere on the Bosch system) so it would have to be a fairly big air leak. Might be the pump leaking all the fuel out of it back to the tank - it can syphon out if a regulating valve fails on the bleeding mechanism.
 
Nah - 300tdi's are not great at starting even if its mild out - they need the glow plugs. Both the 90 and the Disco are the same and other 300tdi's I have driven.

I find that they need the basic glow session to get it to start reasonably quickly.

if a diesel engine has got fuel, compression and it's being turned over at a decent speed it will start - it wont need the assistance of plugs - a good 200 or 300 will start instantly in nearly all weather conditions in this country

any engine that wont start without the use of the plugs is almost certain to have either a fueling or compression problem

the use of glow plugs will help when your starter isnt spinning as fast as it should, they will also help when compression is low or unbalanced
 
Thanks all. really helpful. Set up a gravity feed and left it over night but problem returned once again in the morning so have ruled out air or fuel draining back to the tank. Besides, would have been surprised as Injector pump has had a full overhaul and new lift pump. On earth strap point, connected jump lead from the engine lifting eye direct to exposed metal on the chassis and that made no difference either so have ruled that out.

On much talk of grow plugs, had them out although this starting problem has been a problem through the summer too so i didn't connect the two. Having said that, two are faulty and one was very oily. Will replace them all with the Boche type on earlier recommendation.

I am now thinking that the head gasket may have gone between a cylinder and an oil journal. Again, since I have had it the engine does breath a bit, evidenced in the rocker cover when the oil cap is removed when running. Maybe this is why ! Also compression tested and compression in lower in the cylinder that the oily plug came out of.

Head off tomorrow I think

On running point, it is a bit flat at the bottom of the range although i ruled out the head gasket fairly early on as no sign of mayo in the oil or back pressure in the water. Maybe was a mistake. Will let you know what i find.
 
poor compression, hmm... If its just breathing heavily its probably a cracked or warped piston.

Bear in mind though that it is a popular misconception that a head gasket is ONLY shown up by mayonaise tests.

That only happens if its failed between a water and oil gallery. If its blown as you said, or between there and water, or between 2 cylinders etc then it will show up differently.

Oily glow plug would suggest that cylinder has an issue. Whip the head off and have a look.

PLEASE please while its off do a proper job... Reseat the vavles, change the valve guide oil seals. If you change a piston its worth getting a honing tool and honing the bores, check for scoring. While you have the pistons out for honing, consider new big end shells.

Replace the injector copper washers too.

This sorta stuff won't cost you humungous amounts, but it could potentially get you lots more power back, and will mean the engine runs like it is meant to, and will last much longer.
 
if a diesel engine has got fuel, compression and it's being turned over at a decent speed it will start - it wont need the assistance of plugs - a good 200 or 300 will start instantly in nearly all weather conditions in this country

any engine that wont start without the use of the plugs is almost certain to have either a fueling or compression problem

Well yes I agree, if its got diesel, compression and gets turned over a a DECENT speed it will start, but to be honest in some diesels a decent speed is MUCH faster than a starter could ever achieve and therefore without glows they simply will not start.

Take the 2.5NA (new) just would not start in the winter, cold morning, not a chance, battery would be flat before it would start.

300tdi, it will start in most conditions we get here but even with a good one they do have the bad starting ones, which plenty of them fall into, check my 300tdi 90, its compression was almost sitting on the factory values yet the bugger won't start in the cold without glows. Drag it along and it will start sure, but there your back to the decent speed thing.

200tdi's are different they just start, not quite sure why they are so similar.
 
Again, thank all.

A bit of an update for you all. Long and short is that it was compression.

Popped the head off the other day and it was soon evident that the bores are notably worn, so much so that it is not possible to push the pistons out as the rings are catching on the newly formed lip at the top of the bore. Don't know what the previous owners where running it on. Sand perhaps !

Anyhow, this would explain bad starting, smoking, back pressure in the crank case, lack of torque / power etc,etc.

Anyhow, block is now out and stripped and off for re boring and assembling new pistons and crank shells etc next week. Head is also going for an overhaul with new valves, seats, guides and seals. Have heard 300 heads should not be skimmed. Is their truth in this before I send it packing for a skimming !

So it wasn't fuel after all but a least the whole fuels system has had a good overhaul.

I wanted to do the clutch anyway !

If starting problem persits after this I really will give up. i will do a final pst when engine back in.
 
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