d5 hot starting issues

[noscralc]

Hoping to find someone on the forums who has experienced hot started problems like me.V70 2003 D5.
It starts spot on from cold but once hot is very reluctant to catch-trying to fire
changed fuel filter recently no shouldn't be restriction here, Once running it is perfect pulls like a train -no hesitation or anything just hard to start when hot. I know the egr valve is stuck open as a friend plugged his reader in but nothing else came up am thinking of blanking this as I am led to believe this is causing the excessive black smoke on acceleration but could it also affect the starting when hot?
Have searched the forums but not been able to find much on this problem-surely someone must have come across this.
Any thoughts/advise greatly appreciated.

[skyship007]

Originally Posted by noscralc

Hoping to find someone on the forums who has experienced hot started problems like me.V70 2003 D5.
It starts spot on from cold but once hot is very reluctant to catch-trying to fire
changed fuel filter recently no shouldn't be restriction here, Once running it is perfect pulls like a train -no hesitation or anything just hard to start when hot. I know the egr valve is stuck open as a friend plugged his reader in but nothing else came up am thinking of blanking this as I am led to believe this is causing the excessive black smoke on acceleration but could it also affect the starting when hot?
Have searched the forums but not been able to find much on this problem-surely someone must have come across this.
Any thoughts/advise greatly appreciated.

If you blank the EGR, rather than clean or replace it, the vehicle is classed as unroadworthy, as it is not capable of meeting it's original emissions equipment standards. It's also an MOT failure point. A non functioning EGR will not cause a hot start issue.

There are quite a number of reasons why a diesel might not hot start and the lack of a fault code is a pity.
Poor performance from the electric fuel pump or an air leak into the fuel line before the HP pump does not cause a code with most older diesels. A blown HG can also cause hot start troubles, as can too thin an engine oil in combination with worn rings.
One thing you might try is to prime the fuel system or check the fuel filter is full before hot starting, as that will indicate a bad electric pump or air leak. Air leaks tend to cause an engine to stall in some cases.

[noscralc]

Originally Posted by skyship007

If you blank the EGR, rather than clean or replace it, the vehicle is classed as unroadworthy, as it is not capable of meeting it's original emissions equipment standards. It's also an MOT failure point. A non functioning EGR will not cause a hot start issue.

There are quite a number of reasons why a diesel might not hot start and the lack of a fault code is a pity.
Poor performance from the electric fuel pump or an air leak into the fuel line before the HP pump does not cause a code with most older diesels. A blown HG can also cause hot start troubles, as can too thin an engine oil in combination with worn rings.
One thing you might try is to prime the fuel system or check the fuel filter is full before hot starting, as that will indicate a bad electric pump or air leak. Air leaks tend to cause an engine to stall in some cases.

thanks for your reply
I can hear the electric pump running but don't know how much fuel it's putting out if any, not sure what you mean by prime the system? short of unscrewing the fuel filter is there another way to tell. Can't get my head round why it starts up perfectly from cold and once running from a hot start is fine.hmm

[Bernard333]

You cannot prime your 2003 D5, it does it automatically and in any case your high pressure pump can cope with any amount of air bubbles in the low pressure feed even the electric pump not working will not matter if you have about half a tank, I know this from feeding mine through a clear pipe, made no difference to starting or running. I would have a good look at your injectors. The heavy black smoke is likley to be your intercooler burst rather than EGR.

[Rooster]

A stuck EGR valve WILL cause all sorts of issues including starting issues especially if its stuck open,

If its stuck open it will permanently be pumping exhaust gases back into the intake system choking the engine of fresh air it needs on startup and under load,

The EGR basically cools the combustion process by pushing already burnt gases back into the intake track so it has to try and burn them again, because its not burning as clean it cooler,

Try blanking it off and see if things improve altho i wouldn't use it as a permanent fix

[klunk]

Originally Posted by skyship007

If you blank the EGR, rather than clean or replace it, the vehicle is classed as unroadworthy, as it is not capable of meeting it's original emissions equipment standards. It's also an MOT failure point. A non functioning EGR will not cause a hot start issue.

He's off on one again!! Ignore this advice, Blank the EGR, It will run cleaner- Less black smoke, MPG will improve, You wont be clogging up your inlet manifold and cylinders with cr@p and as a result of that it will go better!

[noscralc]

Thanks for all the replies once again, have decided to bite the bullet and ordered a new egr valve from Rufe (still expensive!).
Have experimented with blanking plates-a full blank brought on the "emissions service message" which I expected but found blanking with a 10mm hole in the blank seemed ok-no smoke, no message but still hot starting issues- will report back when this has been fitted and then go from there with the hot starting if no improvement.

[noscralc]

Latest update.
Valve changed yesterday result-no smoke-hot start seems fine-will see how it goes in a few days but for now looking good!
Was rather surprised it wasn't as clogged up as I expected but there was quite a bit of soot in the cooler tube and I could push the plunger in and out ok but not right some where, anyway it took some of the threads out of the alloy housing when removing the very tight bolts so no going back.
happy today-tomorrow??

[skyship007]

Originally Posted by klunk

He's off on one again!! Ignore this advice, Blank the EGR, It will run cleaner- Less black smoke, MPG will improve, You wont be clogging up your inlet manifold and cylinders with cr@p and as a result of that it will go better!

If you read up about EGR valves you will find that removing them is in fact bad news for a modern diesel. It takes longer for the block to warm up because the hot exhaust gases are not recirculated, the warm up phase is when Carbon deposits form in the cylinders and exhaust system, so prolonging it is not a good idea.
A blocked EGR does have a slight negative effect on fuel economy, but if the MAP is not adjusted to allow for a blanked EGR it makes no real difference to the engine power or the fuel economy (If you take into account the reduced warm up time).
Blanking an EGR is a new MOT failure point and an anti social act, as NOx gas is nasty stuff.
Some insurance companies can use a blanked EGR as a basis for refusing a claim if it is associated with a power increase (That would depend on a MAP change).

[noscralc]

Originally Posted by noscralc

Latest update.
Valve changed yesterday result-no smoke-hot start seems fine-will see how it goes in a few days but for now looking good!
Was rather surprised it wasn't as clogged up as I expected but there was quite a bit of soot in the cooler tube and I could push the plunger in and out ok but not right some where, anyway it took some of the threads out of the alloy housing when removing the very tight bolts so no going back.
happy today-tomorrow??

Hmm looks like I celebrated too soon (story of my life) went to the supermarket today-came out and it was reluctant to start-was fine 1st thing in the morning and runs pulls well once running?
the search goes on!