I got this car and it does this when starting it up. Any ideas what can it be?

 

In case someone can't or doesn't want to see the video, the issue is that after starting, the engine RPM stays around 700 and sounds like a diesel. After a second or two it seems to fix itself.

Thanks

 

Possibly any, all, or some of these:-

• Low oil pressure.
• Wrong grade of oil in the engine.
• Needs Oil change.
• Needs new oil filter.

3 hours ago, unofix said:

Possibly any, all, or some of these:-

• Low oil pressure.
• Wrong grade of oil in the engine.
• Needs Oil change.
• Needs new oil filter.

Since I took it to the mechanic and he did a full service, it can't be an oil change or a filter. His assumption is that it's something with "variable" and that it does take it's time to reach the proper pressure. Excuse my ignorance to the subject.

An oil pump can cause low oil pressure? Could it be something with the power?

The oil pump is mechanically driven off the engine. The pump may be worn and not producing full oil pressure or the oil pick up in the sump for the oil pump may be partly blocked. Is the oil the correct grade ?

Tom @TomsFocus might have an idea of what the problem could be.

10 hours ago, ntelas said:

Since I took it to the mechanic and he did a full service, it can't be an oil change or a filter. His assumption is that it's something with "variable" and that it does take it's time to reach the proper pressure. Excuse my ignorance to the subject.

An oil pump can cause low oil pressure? Could it be something with the power?

A 100bhp model won't have Ti-VCT. (Twin independent variable cam timing).  

I'd say that's a fault with the crank or cam sensors.  The oil pressure is just low because the engine speed isn't fast enough to start with.

The engine light is on so there should be a fault code stored.  

I think I made a mistake by saying it's the 100HP model. Now looking at the registration, it says it's 85kW. The seller had 100HP at the title so I never thought of checking it. Are those all Ti-VCTs? If so, does this change the answer?

 

Apologies for the confusion. If there is a way to check for certain what engine does it have, I will check it.

Also, the check engine light is the L sensor that will be taken care of.

41 minutes ago, ntelas said:

I think I made a mistake by saying it's the 100HP model. Now looking at the registration, it says it's 85kW. The seller had 100HP at the title so I never thought of checking it. Are those all Ti-VCTs? If so, does this change the answer?

 

Apologies for the confusion. If there is a way to check for certain what engine does it have, I will check it.

Yes, that makes a huge difference!  The 115bhp version is Ti-VCT.  And I would now suggest the fault is with the variable cam system.

 

38 minutes ago, ntelas said:

Also, the check engine light is the L sensor that will be taken care of.

Not sure what you mean by this?  Lambda sensor?

1 hour ago, TomsFocus said:

Yes, that makes a huge difference!  The 115bhp version is Ti-VCT.  And I would now suggest the fault is with the variable cam system.

 

Not sure what you mean by this?  Lambda sensor?

Will this get worse, to the point where it can affect idling as well?(that's what a the mechanic I went suggested). This must be expensive to fix.

The check engine according to the same mechanic is a bad catalytic converter. He saw it on the OBD software, cleared it and it reappeared after 2 days.

4 minutes ago, ntelas said:

Will this get worse, to the point where it can affect idling as well?(that's what a the mechanic I went suggested). This must be expensive to fix.

The check engine according to the same mechanic is a bad catalytic converter. He saw it on the OBD software, cleared it and it reappeared after 2 days.

Yes, it will get worse if it's the cam variator.  Very expensive job.  It's basically the cost of a timing belt replacement, plus a bit extra to change the cam variators as well.

While it's running rough like that, there will be some unburnt petrol going into the exhaust.  That petrol can damage the catalytic converter over time.  I wouldn't recommend replacing it until the rough running issue is fixed.

It's also worth noting that the cam variators are powered by oil pressure.  So it is now possible that the oil pressure is causing the rough running fault, as well as the cam variators and the slow engine speed causing the oil pressure fault.  I can't say for certain which of those faults is the correct one.

It's a difficult position to be in, as it's going to be expensive either way.  If you've got the option to return the car and buy a different one, that would be my preference in this case.

5 minutes ago, TomsFocus said:

Yes, it will get worse if it's the cam variator.  Very expensive job.  It's basically the cost of a timing belt replacement, plus a bit extra to change the cam variators as well.

While it's running rough like that, there will be some unburnt petrol going into the exhaust.  That petrol can damage the catalytic converter over time.  I wouldn't recommend replacing it until the rough running issue is fixed.

It's also worth noting that the cam variators are powered by oil pressure.  So it is now possible that the oil pressure is causing the rough running fault, as well as the cam variators and the slow engine speed causing the oil pressure fault.  I can't say for certain which of those faults is the correct one.

It's a difficult position to be in, as it's going to be expensive either way.  If you've got the option to return the car and buy a different one, that would be my preference in this case.

Thank you very much for the details. I hope it doesn't need a repair soon. Returning it is not an option since it was a private seller.

Is there a way I can try to prevent the quick worsening of the issue? If the car is freshly parked, it doesn't do it much. It's only this bad when it's cold.

There isn't really anything you can do unfortunately.