300tdi Cold Start Issue

Johnny8718 · Oct 14, 2011

Hi All. 
 
When I come to my 1996 300 in a morning, I have loads of power in the battery. 
 
Glow plugs light and go out. 
 
I crank the car over, but it won't catch. As soon as I release the key, it stops - refusing to fire. 
 
I have tried holding it on the key with no success. The only way to start from cold is to hold the throttle down and then it does start. 
 
This is not a good idea when cold! 
 
Any ideas? It reminds of the ballast resistor fault on old Cortinas - I am assuming that the Disco does not have one! 
 
Thanks in anticipation, John.

Graham Carter · Oct 15, 2011

Almost certainly glow plug failure, if it starts OK once warm. They tend to fail, and you don't know until all have failed - car will normally start with just one available. Glow plug light does not tell you anything - it purely tells you when the timer has switched off.

Take glow plugs out and connect to a battery - they should glow red very quickly. They're a cheap fix if they do fail.
Cheers!

Johnny8718 · Oct 24, 2011

I wasn't entirely sure but thought it best to rule out this possibility.

Unfortunately, new glow plugs and the issue still exists.

Help!

jamesmartin · Oct 24, 2011

check for air entering pump

johnboy1983 · Oct 24, 2011

It may be worth checking your lift pump

Graham Carter · Oct 26, 2011

My 300Tdi in Zimbabwe developed a problem where if it was left pointing uphillfor a while, starting was very difficult. Point it downhill and it was fine. This was caused by a leaky diapraghm in the lift pump causing all the fuel in the lines to drain back into the tank. If you are parking on a slope, try parking the other way round. If that helps, replace lft pump (they're cheap and easy), and then my next bet would be air leaking in from a joint.

Cheers!

Johnny8718 · Oct 27, 2011

Thanks all. I will have a look at the lift pump and let you know. John.

skires · Oct 27, 2011

Any leaks from the injection pump? Around throttle shaft ( common )?

cornish rattler · Oct 27, 2011

had this problem just before last christmas bought a set of glow plugs off ebay chucked them in and still had same problem turning over slow after giving it 3 lots of heat and eventually firing then bought another set of glow plugs from paddocks ( a good set not britpart ) still had same problem, anyway i ran with it for a while as i was out of work and couldn't afford to go in too deep and the car ran and started ok once it had started.

anyway in the end i decided to remove and clean out the sedimentor, refitted it and after that it started with one lot of heat when cold and is still the same today.

so would look at the sedimentor, even if you don't find anything at least you will know its been cleaned out, hope this helps.

Johnny8718 · Oct 31, 2011

cornish rattler said:
had this problem just before last christmas bought a set of glow plugs off ebay chucked them in and still had same problem turning over slow after giving it 3 lots of heat and eventually firing then bought another set of glow plugs from paddocks ( a good set not britpart ) still had same problem, anyway i ran with it for a while as i was out of work and couldn't afford to go in too deep and the car ran and started ok once it had started.

anyway in the end i decided to remove and clean out the sedimentor, refitted it and after that it started with one lot of heat when cold and is still the same today.

so would look at the sedimentor, even if you don't find anything at least you will know its been cleaned out, hope this helps.

Thanks. I have searched the net and have asked a few questions with specialists. No one seems to know the exact answer.

One firm said that I needed to re-earth the engine and body. I have cut a set of jump leads up, run one wire from the battery earth to the engine and another from engine to body. No change.

Another asked me to check for a feed at the plugs. That's OK.

No fuel leaks in the engine bay.

The filter sounds a good point. I must admit that since buying the car a couple of months ago, I haven't serviced it and the filter does look quite old. I will change it in the next few days and will report back on the answer.

Cheers, John.

jamesmartin · Oct 31, 2011

fuel wont necessarily leak as its sucked upto lift pump ,check for good clean feed to injection pump a clear plastic pipe in beteen filter and front banjo bolt on injection pump is a good way

Johnny8718 · Nov 3, 2011

Fed up and confused!

New fuel filter and still the same.

James. If I do find some pipe and there are bubbles in the line, how do I solve this?

What I can't understand is how it will start well all day after struggling somewhat in the morning. If there is air in the system, will this not pose a problem all day?

Any ideas would be appreciated. This thing will be a pig to start when it gets colder - I can see it now!

Thanks, John.

jamesmartin · Nov 3, 2011

takes time for air to leak in sometimes and rebleeds itself once run, if you do have air, you need to start at sender unit under carpet and cover in boot ,then sedimentor behind chassis rear rh wheel best bypassed, then filter ,then lift pump ,

Johnny8718 · Nov 3, 2011

jamesmartin said:
takes time for air to leak in sometimes and rebleeds itself once run, if you do have air, you need to start at sender unit under carpet and cover in boot ,then sedimentor behind chassis rear rh wheel best bypassed, then filter ,then lift pump ,

Ahhh! The sedimentor is behind the chassis?? I assumed that this was part of the filter. Is it best to bypass or replace/repair?

Sorry for all the questions. However many I ask, the sedimentor will be next this week!

Thanks, John.

jamesmartin · Nov 3, 2011

bypass it isnt needed you have water drain on filter in engine bay no problems i learned by asking its the best way

scrappyloz · Nov 3, 2011

I had a very similar problem to you. It turned out that the small fuel return lines on the injectors one had split slightly. I replaced them all and its been fine since

discomania · Nov 3, 2011

Johnny8718 said:
I have tried holding it on the key with no success. The only way to start from cold is to hold the throttle down and then it does start.

This is not a good idea when cold!

On that note, I see what you mean, but thats exactly how the Bosch diesel injection pump's cold start does work.

You deck the throttle, as soon as it starts and I mean the instant, let go of the throttle and it won't rev any higher than normal start ups.

I do it in the real cold all the time - it starts much cleaner too.

However - it SHOULD start without that, so your glows could be shot, but then again, I know plenty of them that need decked throttle even on GOOD (Beru/Bosch) new plugs.

So, if it starts no bother with full throttle, then thats the way to behave.

I will throw this in now, DO NOT DO THIS ON A LUCAS PUMP.

However, as other posts are saying, this can also be a sign of air in the fuel etc...

Johnny8718 · Nov 4, 2011

discomania said:
On that note, I see what you mean, but thats exactly how the Bosch diesel injection pump's cold start does work.

You deck the throttle, as soon as it starts and I mean the instant, let go of the throttle and it won't rev any higher than normal start ups.

I do it in the real cold all the time - it starts much cleaner too.

However - it SHOULD start without that, so your glows could be shot, but then again, I know plenty of them that need decked throttle even on GOOD (Beru/Bosch) new plugs.

So, if it starts no bother with full throttle, then thats the way to behave.

I will throw this in now, DO NOT DO THIS ON A LUCAS PUMP.

However, as other posts are saying, this can also be a sign of air in the fuel etc...

Thanks. I have owned loads of diesels and this is the only one I have had issues with. I have actually changed the glow plugs for new ones and it's exactly the same. The list is getting bigger by the day and I wonder if it's worth keep throwing money at it if after all said and done, I can get it to start with some throttle.

Here's another question for everyone relating to this same problem......

When I turn the ignition on, there is a buzzing sound coming from around the injector pump area. Is this something that rings a bell, anyone had this issues, could it be MY ISSUE?

Thanks once again, John.

jamesmartin · Nov 4, 2011

yours must be edc then ,edc fuel pumps do this with ignition on ,glow plugs shouldnt make a real difference on tdi unless exceptionally cold , poor starting is usually down to low compression easily checked as will breathe heavy out of filler if cap removed but not so likely on tdi, or fuel issues ,like air in fuel,retricted fuel .worn pump ,poor injectors most of which would give other symptoms when running,air would be place to look first

GRATCH · Nov 4, 2011

Could be the engine stop solenoid. May have a ****ty connection which stops the solenoid letting fuel through and thus won't start.

300tdi Cold Start Issue

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