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Medved77

530D not starting when warm

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I'm trying to help my friend with his 530D,E39 touring, manual with 215k miles.

 

 

Overall it runs well but often when you try to restart the car after a brief stop e.g. when filling up with fuel, the car won't turnover.

 

 

We can get round this by spraying brake disc cleaner into the air intake and turning the key in the ignition simultaneously however this is proving somewhat inconvenient especially if he's the only one in the car.

 

 

I've read other posts pointing to the cam shaft sensor, fuel pump(s), fuel filter, injectors and others. Wondered if anyone was able to rule any of the above items out given the workaround we've found?

 

 

I've attached some of the pressure readings from INPA if that helps. I didn't take a screen shot but all of the injector values were very similar to each other.

 

 

Thanks in advance for any replies. 5bdf6a07abab9c25ea2ed8fdc8acdbb3.jpg

 

 

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Not sure why it starts the way you suggest but my 330d had a warm no start. No fault codes but I replaced both cam and crank sensors and it's been spot on ever since.

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My first 530d had very similar issues, replaced cam sensor and was perfect after. 

 

I can't say I tried starting it with easy start mind you !

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If it starts with aid of brake cleaner into intake manifold it must be fuel pressure issue. In this case the most likely cause is leaky injector. Have the injector leak off measured. Injector correctional values don't correlate with possible leak off.

Edited by Clavurion

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Thanks for the responses, we were going to change the cam sensor this weekend but seems it would make more sense to test the injectors before throwing money at parts.

 

Clavurion - Can you offer any advice on how to measure the injector leak off?

 

Is this something I can do with INPA/Dis or is it a hardware test that I'll need some kit for?

 

Would like to avoid paying garage fees if possible.

 

Thanks for the replies.

 

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32 minutes ago, Medved77 said:

Can you offer any advice on how to measure the injector leak off?

 

You will need a leak off kit or cups/syringes and suitable diameter hose.

 

Remove leak off line on top of injectors. Clamp/compress the leak off line after injector connectors. Measuring devices on the injector leak off connecting points. Run engine, max leak off on idle 20 ml @ 2 mins.

 

Paluuvuoto.jpg

Edited by Clavurion

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If the diesel is like the petrols the ecu must get a signal from the CPS to show the starter motor is turning the engine over before it delivers any fuel 

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^ that makes sense and why a compression engine would fire when a 'fuel' is introduced.

 

Clavurion certainly knows more than I but I'd have thought one or two leaky injectors might cause rough running and unlikely all would be so bad it wouldn't start? Especially when it starts cold but not warm?

 

Cam/crank sensors are a common fail, susceptible to heat in my experience, relatively inexpensive and easy enough to fit and known not to throw up a code so i'd start there i think.

 

 

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1 hour ago, duncan-uk said:

^ that makes sense and why a compression engine would fire when a 'fuel' is introduced.

 

Clavurion certainly knows more than I but I'd have thought one or two leaky injectors might cause rough running and unlikely all would be so bad it wouldn't start? Especially when it starts cold but not warm?

 

Cam/crank sensors are a common fail, susceptible to heat in my experience, relatively inexpensive and easy enough to fit and known not to throw up a code so i'd start there i think.

 

 

 

I didn't quite catch what you were trying to say. Usually one leaky injector can cause the problem so that rail pressure doesn't rise high enough for engine start and in many cases the leak off problem is worse with a (half) warm engine. If cam or crank sensor fails it won't start with aid of other fuel like brake cleaner, it would only run as long as that other fuel is introduced. 

By the way never use easy start (ether) on diesel engines as it's too fast burning and has low auto ignition temperature.

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Thanks for all the replies.

 

I've bought a leak test kit which arrives tomorrow. Also got a cam sensor on reserve from ECP.

 

Will test the injectors first, then depending on results change the cam sensor.

 

I'll update with the results tomorrow.

 

Thanks again.

 

Sent from my SM-N910F using Tapatalk

 

 

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Well that was pretty conclusive. That was after 25 seconds. 843118d4036a5732b4843119b735afee.jpg

 

Sent from my SM-N910F using Tapatalk

 

 

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I didn't quite catch what you were trying to say. Usually one leaky injector can cause the problem so that rail pressure doesn't rise high enough for engine start and in many cases the leak off problem is worse with a (half) warm engine. If cam or crank sensor fails it won't start with aid of other fuel like brake cleaner, it would only run as long as that other fuel is introduced. 

By the way never use easy start (ether) on diesel engines as it's too fast burning and has low auto ignition temperature.

 

Aah I hadn't appreciated that a leaky injector would bleed of the fuel pressure. I was thinking of it dripping a bit or not passing enough hence my suggestion of rough running.

 

Thinking too was a duff sensor stopped the fuel hence the introduction of brake cleaner got it firing by compression.

 

As I said you know more

 

 

 

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1 hour ago, duncan-uk said:

 

Aah I hadn't appreciated that a leaky injector would bleed of the fuel pressure. I was thinking of it dripping a bit or not passing enough hence my suggestion of rough running.

 

Thinking too was a duff sensor stopped the fuel hence the introduction of brake cleaner got it firing by compression.

 

Like you said diesel injector leak off is often misunderstood. The working principle of commonrail injector is that there is same rail pressure on both sides of the needle so only small spring force is needed to keep the needle closed. When injector solenoid is activated the leak off line on top of injector is opened releasing pressure from the top cavity and pressure in the lower cavity opens the needle. So a small amount of leak off is normal due to working principle. When the injector internal gasket fails the rail pressure is causing fuel leakage to leak off line dropping the rail pressure.

 

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Injector replaced today, engine now turns over quicker and starts when cold and hot.

 

Result.

 

Sent from my SM-N910F using Tapatalk

 

 

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