Issues starting when warmed up?

[jw1981uk]

Hi Guys I am new to the forum,

 

 I have an issue where as when I start the car first thing in the morning its first turn of the key every time.

 

If I get the engine up to temperature then it can turn over a good few times before starting

 

The car has been plugged in at skoda and a vw specialist with no fault codes.

 

It only happens when the engine has warmed up? Its not slow at turning over the starter motor and battery are fine

 

I was told there is a common sensor that fails temp sender or something like that?

 

Any help appreciated its driving me mad now lol

[Anddenton]

My bet is the battery, regardless of what any garage says.

Apparently with these cars when cold fuel is injected straight away when starting, but when hot a minimum crank speed needs to be met before fuel is supplied. As a battery gets weak it can fall slightly short of this minimum crank speed although not noticeably.

Some have found this to also be a failing starter motor but for cost a battery is the first thing to try.

You could test the theory by trying to jump start the car when warm and see if it makes a difference.

[flying pig]

My bet is the battery, regardless of what any garage says.

Apparently with these cars when cold fuel is injected straight away when starting, but when hot a minimum crank speed needs to be met before fuel is supplied. As a battery gets weak it can fall slightly short of this minimum crank speed although not noticeably.

Some have found this to also be a failing starter motor but for cost a battery is the first thing to try.

You could test the theory by trying to jump start the car when warm and see if it makes a difference.

Yup. I'd put my house on it being the battery. I had a similar issue not long after I bought my car. It would start no problem when cold, however after a run and after the engine was warm, the engine would turn over and then make one hell of a rumbling noise before it would cut out. A failing battery manifests itself in many different ways on the Octavia.

I changed the battery and all has been good for the past three years.

Hope this helps & good luck.

Edited 31 May, 2014 by flying pig

[nick74]

I agree with the above. Change the battery and if that fails to cure it then change the starter motor.

A lot of garages misdiagnose this as being a problem with the temperature sensor, as sometimes disconnecting the sensor will allow the engine to hot start more easily . That doesn't mean the temp sensor was faulty, it just means you're fooling the ECU into thinking the engine is cold when it isn't, allowing it to go into cold start mode and ignore the cranking speed.

[podgie35]

Iv got the same problem. Changed my battery and still the problem is there.

Iv been told that cause the car is turning over it's not the starter motor.

I am still lost as wat is can be. Do you think it's worth renewing the injector seals.

Thanks sara

[VrsMule]

I have this problem on the wife's A3. Changed the battery and still does it. We are getting the cam shaft position sensor fault code so will go for that.

[nick74]

Iv got the same problem. Changed my battery and still the problem is there.

Iv been told that cause the car is turning over it's not the starter motor.

I am still lost as wat is can be. Do you think it's worth renewing the injector seals.

Thanks sara

If a garage has told you that take the car to another one who knows what they are talking about! This is a well known problem with VW PD diesels.

The starter motor only needs to be cranking the engine fractionally too slowly for hot starting to become difficult as the ecu won't allow a hot engine to start if the cranking speed is too slow.

The reason cold starting isn't affected is because the ecu ignores the cranking speed when the engine is cold.

[Tall]

I had this on a Merc Sprinter, an injector was leaking off. Have a look at the fuel return pipes (if there's any clear bits) and see if there's any big air bubbles. It was a common problem on the 2.5 cdi engine, worst around 02 - 04 year.

[nick74]

I had this on a Merc Sprinter, an injector was leaking off. Have a look at the fuel return pipes (if there's any clear bits) and see if there's any big air bubbles. It was a common problem on the 2.5 cdi engine, worst around 02 - 04 year.

That only applies to common rail engines, the PD system used on these engines is very different and doesn't have injector leak off pipes as such.

 

Whereas a common rail system has to see a certain fuel rail pressure whilst cranking to start, a PD has to see a certain rpm during cranking to start.

[Hunty278]

My dad had this problem on his Golf Plus 1.9 TDI PD 105Bhp. I researched it online and heard all the Cam position Sensor and Temp Sensor remedies. In the end, he got the starter changed. The problem went away and has not re-occurred since. That was a year ago now.

 

HTH

[nick74]

If you're getting specific fault codes relating to a particular sensor, then fine, replace that sensor. But 99% of the time on these where there are hot starting problems with no fault codes stored, and perfect cold starting, then it's either the battery or starter motor.

[Tall]

That only applies to common rail engines, the PD system used on these engines is very different and doesn't have injector leak off pipes as such.

 

Whereas a common rail system has to see a certain fuel rail pressure whilst cranking to start, a PD has to see a certain rpm during cranking to start.

My apologies, didn't give a thought to the common rail aspect.

[whitep]

I had this, turned out to be the butterfly valve (Anti Shudder Valve) in the EGR manifold. it was coked up and when it got warm it became sticky. I took it off and gave it a good glean with Mr Muscle and a toothbrush.

[nick74]

My apologies, didn't give a thought to the common rail aspect.

 

PDs are a bit of an oddity really and can suffer with occasional issues that don't affect common rail engines. On the positive side they are immune to quite a few problems that can blight some common rail systems!

[mk2cliffy]

I've got this problem but I've had the car 18 months and my dad owned it before me with a warm start problem. Could it still be the battery getting weak after all that time?

[mk2cliffy]

After more than 2 years surely the battery would be useless by now?

[podgie35]

So I'v now had my starter motor check my a specialist and it's working fine. He has said it's a diesil problem. So it's going on a vag com tomorrow to see if that can point us in the right direction.

Any other ideas

Cheers sara

[podgie35]

So I'v now had my starter motor check my a specialist and it's working fine. He has said it's a diesil problem. So it's going on a vag com tomorrow to see if that can point us in the right direction.

Any other ideas

Cheers sara