200di diesel not starting when hot?

[Diesel Donkey]

Why does my 200di diesel engine start when cold first time every time and not start when hot ( completely flat battery symptom ) battery tested and ok, 14.6v on tickover all earths cleaned and re-seated, an extra earth from chassis to engine block, new starter motor, new starter switch, I have even tried the battery from my daily driver which I know is good and still get the same symptoms. Could it be the wiring from the starter switch to the starter motor breaking down which is the only thing I haven't tested yet?

 

[mainline]

Why does my 200di diesel engine start when cold first time every time and not start when hot ( completely flat battery symptom ) battery tested and ok, 14.6v on tickover all earths cleaned and re-seated, an extra earth from chassis to engine block, new starter motor, new starter switch, I have even tried the battery from my daily driver which I know is good and still get the same symptoms. Could it be the wiring from the starter switch to the starter motor breaking down which is the only thing I haven't tested yet?

Were is the battery located

 

[Diesel Donkey]

Were is the battery located

Hi Mainline, the battery is located under the passenger seat.

 

[mainline]

Does it try to turn over when hot at all ?

Is the dash going dim/lights when trying to start ?

Have you a voltmeter ?

 

[Diesel Donkey]

Were is the battery located

Does it try to turn over when hot at all ?

Is the dash going dim/lights when trying to start ?

Have you a voltmeter ?

When hot it is like the battery is completely flat, when tested on cranking it the battery dropped to about 7.6v

 

[brianmoooore]

when tested on cranking it the battery dropped to about 7.6v

Measured from where to where?

 

[mainline]

When hot it is like the battery is completely flat, when tested on cranking it the battery dropped to about 7.6v

It could be that the engine is tight when hot ?

It could be the starter motor when hot ?

 

[brianmoooore]

If it's pulling a good, fully charged battery down to 7.6 volts, then something is quickly going to get hot if it wasn't before. Between where and where is the 7.6 volts?

 

[Diesel Donkey]

Measured from where to where?

+ to - on battery terminals.

 

[Diesel Donkey]

It could be that the engine is tight when hot ?

It could be the starter motor when hot ?

It is a brand new starter, new starter sw, all earths cleaned and re-seated and I even added an extra earth from chassis to engine block.
This is a fairly recent issue as it used to run without any problems?
It will run all day without issues, only issue is when trying to start again until it cools then starts perfectly?

 

[mainline]

It is a brand new starter, new starter sw, all earths cleaned and re-seated and I even added an extra earth from chassis to engine block.
This is a fairly recent issue as it used to run without any problems?
It will run all day without issues, only issue is when trying to start again until it cools then starts perfectly?

You need to measure the amount of current the starter is taking when hot and if the engine is turning freely.

 

[Diesel Donkey]

You need to measure the amount of current the starter is taking when hot and if the engine is turning freely.

To do that do I connect my multimeter to the starter and earth?

 

[Diesel Donkey]

Thanks Mainline, I will get myself a clamp on ammeter and will report back when tested

 

[Diesel Donkey]

Hi guys, sorry for the absence, my other motor took priority, gearbox problem and some welding issues only to be expected on a 33 year old vehicle, all sorted now.

Back to my other project on my 59 year old, after some more testing decided to renew the negative and pos battery leads, connected everything back up turned the ignition on and it immediately started (not good ) as it was only in the first position checked everything through to see if I had connected everything right.

I then took the ignition switch out and tested the terminals with my multi meter, off to first position immediately beeped out on the continuity function so a new ign switch was naff.

I put my old switch back and started the old girl, run her for a good while then turned her off and she started up again, first turn of the key.

Hopefully things are sorted now and it was either of those cables breaking down under load when hot?

Thanks for all your help guys.