Leon mk1 cupra tdi starting issues

[hendocupra555]

Hi folks, has anyone ever had a problem with their Leon not starting? 9 times out of 10 she will start no problem at all but then I do exact same process of letting glow plug light go out and then she will think about starting but then doesn't, the next time I turn her over she will eventually start after a bit of spluttering. I don't know if it's a coincidence or not but it happens more easily when I run the fuel down. So I normally only run it to about half a tank then refuel. Anyone with any ideas or similar experiences please let me know.


Ps. I have changed fuel filter, the little "valve" on top of the fuel filter.

 

[masterfrodo]

Mine can be a bit slow at turning over in the mornings but eventually starts. Other mornings it starts straight away. Not sure why

 

[sockpuppet]

I have the same thing, it's very intermittent but more pronounced when the car is hot and if I have the aircon running when starting the car.

I have used injector cleaner and starting using V power diesel and Miller additive, it's too early to say if it's made any difference, but the car hasn't failed to start so far. Im going to change the fuel filter this week as well to rule that out.

There is a theory that the starter motor isn't turning fast enough so the engine doesn't turn fast enough to start. When it does fail to start it's normally at about 600 rpm for a second and either picks up to 900rpm or stalls.

Have you chacked for any fault codes? Mine is completely clear of any codes.

 

[hendocupra555]

Yeah I've checked for codes but nothing. First time I noticed it the car was parked uphill so I thought it might be fuel running back to the fuel tank if that's possible. But since then it's very random. It's been going on for a wee while now but starting to annoy me. Wouldn't mind being able to run the car until the tank is near empty rather having to fuel it up at the halfway point.

 

[BadBoy03]

Just a thought, have you considered the fuel pump? My old leon (petrol) started playing up randomly on start up. For example i parked up for half an hour, came back and it wouldn't start. I let it sit still for a while as i didn't want to overload attempts and it started after 10 mins or so. Eventually car just wouldn't start after work, but had been fine in the day. RAC checked it over and after process of elimination determined it was the fuel pump in the back seat. To get it started he kicked the lower side of the drivers door/chassis to get the fuel moving, then it started. We then went straight to the garage for a new pump. You should here a faint hum when the key is in the ignition, this is the pump. (although i have no clue about diesels so could be wrong).

 

[hendocupra555]

Is it in the back seat? I was told the fuel pump was inside the tank? Maybe it could be that. Although you do hear the noise you are talking about. Thanks for your reply.

 

[BadBoy03]

Is it in the back seat? I was told the fuel pump was inside the tank? Maybe it could be that. Although you do hear the noise you are talking about. Thanks for your reply.

The fuel pump is accessed underneath the rear drivers side seat (presuming that is where the fuel tank is). By moving out the seat you can access the fuel pump without disturbing the tank. It is a relatively simple job to replace but bit pricey on certain pumps. If you are hearing the noise it probably means it's ok. It was only after it had gone that i realised no noise engaged with the ignition. I really hope you can find some answers. Without fault codes it's tricky. My Cupra played up starting but the fault code read 'Camshaft sensor' and once replaced it was perfect again. Shame there are so many possibilities on start up. Power, sparkies, starter motor, fuel etc. I hope one these bright dudes on here will have you an answer ASAP. keep trawling relevant threads, you never know!

 

[s1 evoloution]

have you checked for any air bubbles in the fuel line. i had air bubbles on my fuel line was not starting until i slackened the main injector line on the engine to no,3 cylinder put a big rag over top to stop fuel going over engine turned engine over for about 10 seconds then stopped checked rags and fuel line and tightened injector back up .air bubbles gone car started first time every time.

 

[hendocupra555]

I haven't checked that. It has been going on for a while so never thought to try that as I assumed if it had been air in the system it would have worked its way out by now?

 

[s1 evoloution]

if you have clear fuel line going to your pump you can see any little air bubbles in the fuel system. it used to be 2 bolts to bleed air and diesel on diesel injection pumps most of that has changed to the new set up. they say they are self bleeding but you still see air bubbles in the fuel system. wether you changed a diesel filter run out of diesel or the diesel sludge in the tank has been drawn up with good diesel to cause problems. millers diesel additive makes the engine feel smoother driving regardless of age or mileage of engine.

 

[hendocupra555]

Thanks very much will look into that, much appreciated

 

[teddycatkin]

When starting from cold--try turning on ign until heater light goes out-then repeat the proceedure -then wait a second then turn all the way to start engine---? this usually works by giving the glow plugs an extra warm up time