Car wont start.

[MJ]

Crank sensor failure will stop the vehicle starting. Cam sensor failure will just cause it to crank a few times then start.

 

[shnazzle]

No one has actually checked this but all said wont be battery cos its turning over well enough.

You'd be surprised. Imagine a 5 year old trying to kick start a motorcycle. It's turn over, but not enough power to get it going

 

[STU3Y]

Crank sensor failure will stop the vehicle starting. Cam sensor failure will just cause it to crank a few times then start.

So more likely to be crank sensor then. so how exactly do I get it checked or check it myself. Give me the dummies version

 

[STU3Y]

You'd be surprised. Imagine a 5 year old trying to kick start a motorcycle. It's turn over, but not enough power to get it going

it tries and tries and tries with no change in effort, normally i would expect it to deteriorate slightly as i have had this before on different car, so I would think the batt is ok

 

[shnazzle]

it tries and tries and tries with no change in effort, normally i would expect it to deteriorate slightly as i have had this before on different car, so I would think the batt is ok

It's just an idea But very easily tested. Hook it up to another battery and if it starts first time...you know. If not, then at least you've eliminated another thing.

There's a difference between a flat battery and a battery not putting out the 13.x V it should

 

[STU3Y]

It's just an idea But very easily tested. Hook it up to another battery and if it starts first time...you know. If not, then at least you've eliminated another thing.

There's a difference between a flat battery and a battery not putting out the 13.x V it should

Will try it next time it doesnt start. I had it on my scooby, where batt was fully charged etc but still wouldnt start. think it was. down to ampage or something, basically the strength required to start rather than power lights etc. Rac mechanic originally said he thought a car not starting call was always going to be the batt but was happy it wasnt this time. I will rule it out for sure next time

 

[STU3Y]

So if i am right the likely problems could be,
Battery
Fuel filter
Fuel pump
Crank sensor
Camshaft sensor
Glow plugs
Injectors

Question 1:
What order would you recommend checking the suggested faults?
Question 2:
Can anyone tell me the location of each sensor and possibly how to change them

 

[STU3Y]

I would check fuel system is being primed, taking a fuel pipe off, post fuel filter and seeing if you get a nice squirt of fuel on either ignition prime or cranking of engine.

Can you tell me which pipe to disconnect to do the above and which end.

 

[MJ]

It won't be the glow plugs.

Either number 1 or number 2

 

[Dan FR]

So if i am right the likely problems could be,
Battery
Fuel filter
Fuel pump
Crank sensor
Camshaft sensor
Glow plugs
Injectors

Question 1:
What order would you recommend checking the suggested faults?
Question 2:
Can anyone tell me the location of each sensor and possibly how to change them

Battery - very unlikely from your description of it cranking over well
Fuel filter - unlikely or it would also be an issue once running - for the cost of part and ease of changing its worth doing
Crank sensor - unlikely in my opinion - Can't see it only failing when the car has been left for days and once running its fine. Plus if the camshaft sensor was working then im sure the crank sensor would throw a fault - you can check this with VCDS or even the torque app, check RPM when cranking
Camshaft sensor - no, as MJ mentioned it causes a delay in starting but it will fire up. My mates GF's Golf has had this fault since she bought it and she just lives with it.
Glowplugs - Nope, not in this weather with outside temp in double figures, from memory i dont think the glowplugs even operate when coolant is above 7 degrees c for starting purposes
Injectors - again unlikely as the car is running fine once its going.

I still think its a fuel supply problem, much like old diesel cars used to suffer with if you ran them dry of fuel. I'm not sure if diagnostic equipment can tell you current fuel/injection pressure (not looked at an EDC16 diesel for a while)

My guess is it is still fuel related. Do these cars have a non-return valve of some description? Is it in the filter, or in the line somewhere between engine and the return to the tank?

Can you tell me which pipe to disconnect to do the above and which end.

Either 3 or 4 but i cant remember which one is the feed and which is the return. Fuel should be flowing through them all though. I'm sure MJ will be able to help further

 

[Dan FR]

Just found this, worth a read
http://www.mk5golfgti.co.uk/forum/index.php/topic,71467.0.html

 

[shnazzle]

That's quite a scary resemblance to this thread

 

[MJ]

I'm sure if you disconnect pipe 1 and turn the ignition on then the lift pump will prime and fire out a burst of fuel it certainly should while cranking. If not the lift pump has had it.

So I'm with DanFr on this.

Pull the pipe off and check it. Failing that get the back seats out and put 12v to the pump and see if it kicks into life.

 

[STU3Y]

So what rpm shoukd I be looking for when cranking? should I pull any fuses to stop ot starting?

 

[STU3Y]

1. lifted back seat can hear pump very easily when turning ignition.

2. removed pipe one and turned ignition. About 20ml of diesel comes out every time. nice and clean.
what next

 

[STU3Y]

started car qwith torque loaded. said revs were 211 when cranked then when up to 838 or similar. second time of trying showed revs of 117 then up to 838ish

 

[MJ]

Does it smoke once it starts?

 

[STU3Y]

Not that I can see.

 

[STU3Y]

Please dont shoot me for saying this but seen this video as way to check battery. is it something worth trying?
https://www.youtube.com/watch?v=viltQBg2jOQ

 

[MJ]

As already suggested - boost it from another vehicle when it won't fire.