Help needed engine wont start unless the oil cap is removed!

[bulbsubaru]

Hi guys, if recently got a leon fr tdi 170, the issue is the car was a non runner when I got it, the previous ower said it just cut out on him and would not restart! I was hoping the fuel pump had died, but not to be, if you take the oil cap off it fires up into life, as soon as you put it back on the car starts hissing and whistling and cuts out, I'm now worried the engine is no good, although it sounds fine without the cap on? What other probable causes could it be other than a blocked pcv system, turbo? Head gasket? And how do I go about finding the problem,? Hope someone else has rectified the same problem, Thanks in advance Richard.

 

[Sharpy]

Could be a blocked exhaust / DPF / EGR Valve, the EGR is easy to remove and check / clean then i'd look at the DPF...

 

[bulbsubaru]

Could be a blocked exhaust / DPF / EGR Valve, the EGR is easy to remove and check / clean then i'd look at the DPF...

Forget to mention theres no dpf or egr both removed and mapped out

 

[Sharpy]

Forget to mention theres no dpf or egr both removed and mapped out

oh.... Still could possibly be a blocked exhaust.

Couple of other possibilities are a turbo related issue, that would also explain the noises and an issue with the head gasket meaning gasses are getting where they shouldn't.

I think you will need a well planned process of elimination to get to the bottom of it as there are a few possibilities.

 

[bulbsubaru]

oh.... Still could possibly be a blocked exhaust.

Couple of other possibilities are a turbo related issue, that would also explain the noises and an issue with the head gasket meaning gasses are getting where they shouldn't.

I think you will need a well planned process of elimination to get to the bottom of it as there are a few possibilities.

I know still haven't got the car home yet as I doesn't have a towing eye with it and so far iv hit a wall trying to find one local, I'm going to start with the breather system, then the exhaust I will detach it from the turbo to see if that makes a difference? Then look at the turbo, maybe do a compression test then to see if the gasket has gone?

 

[R3k1355]

I'd start with the breather system, check all the intake pipework as well make sure nothing has gotten in.

Sounds like a very weird problem.

 

[bulbsubaru]

Quick update! Got the car home late Friday night, managed to take a look at it today, breather system seems fine, so I disconnected the egr exhaust pipe and she idled fine with no wheezing noises, when revved I had quite a bit of oil out the pipe, so I took the inlet elbow off the turbo and found the impeller is moving around all over the place in out side to side it doesn't feel like its attached to the exhaust impeller? Turbo off next to see how much damage has been done?