PCV valve

[serendipity]

I'm trying to work out why my Yaris stalls in hot weather. I noticed today that with the engine idling and the oil filter cap off that there is  positive air pressure from the filler cap (i.e air is blown out of the cap). This suggests me the the PCV valve may not being functioning correctly and possibly jammed shut.

Before I pull it out I was wondering if anyone had any advice?

 

 

[ZZT86]

Should flow if you blow into 1 side but not the other. If faulty replace it with new, they're not expensive but your engine is 😉

[serendipity]

Cheers. I pulled it out and it does what you say so seems to be OK. I cleaned it with some throttle body cleaner.

Still curious if others have noticed pressure blown out of oil filler when cap removed at idle. 

[campbeam]

12 hours ago, serendipity said:

Cheers. I pulled it out and it does what you say so seems to be OK. I cleaned it with some throttle body cleaner.

Still curious if others have noticed pressure blown out of oil filler when cap removed at idle. 

I will check the girlfriend's Yaris tomorrow and give a definite answer.

Suggest that you have a read of the following link that may give you some hints of what to check.

https://www.ifixit.com/Answers/View/62340/stalls+after+engine+heats+to+operating+temp

 

I have recently replaced the spark plugs. Previously, I have replaced the MAF sensor and an ignition coil. The crankshaft position sensor also got replaced after a check engine light had come on. Removed and cleaned the existing sensor and the CEL went out. Still ended up replacing the sensor.

[campbeam]

Just checked the girlfriend's Yaris and there is air blowing out of the oil filler cap.

There is not too much airflow unlike my previous Honda Prelude which showered me in oil when I was trying to top it up. Lesson learnt. Now I don't do any oil top up with the engine running.

[serendipity]

Thanks very much checking. The airflow out the filler cap sounds very similar to ours so I'm happy the PCV valve is working as it should. 

I pulled the MAF/intake temp. sensor out this afternoon and noticed that one of the two temp. sensor wires is very black. I'll try cleaning it once I get some MAF cleaner and hopefully this might improve the stalling.

The stalling is very dependent on ambient temperature. It seems to need to be above about 35C for stalling to happen.

thanks again

 

 

Edited October 23, 2020 by serendipity

[campbeam]

5 hours ago, serendipity said:

I pulled the MAF/intake temp. sensor out this afternoon and noticed that one of the two temp. sensor wires is very black. I'll try cleaning it once I get some MAF cleaner and hopefully this might improve the stalling.

MAF sensor wires certainly need to be cleaned. Suggest that you look at cleaning the throttle body, checking the air filter and the spark plugs. All help to have the engine idling and running nicely.

I learnt the hard way that the condition of the spark plugs impacts the life of the ignition coils. Ended up having to replace one of the ignition coils when it failed then replacing the spark plugs. I reckon that if I had replaced the spark plugs much sooner then the ignition coil may not have failed.

When the girlfriend complained recently about the engine not running the best, I replaced those spark plugs with long life iridiums; Denso IK16TT. Also be wary of fake parts.

https://www.ebay.com.au/itm/4-X-DENSO-IRIDIUM-SPARK-PLUGS-IK16TT-for-Toyota-Corolla-ZZE122R-1ZZFE-BKR5EIX-11/132603888741?epid=847195733&hash=item1edfcec465:g:ZSQAAOSw8nFemiSm