Error code P0172 VVTLi

[steve_weegie]

What seals are you talking about Meatball?? I'm no expert on the 'yota engine, but the only seals i can think of that would let oil into the combustion chamber are the valve stem oil seals

Is it under warranty??

[meatball]

No warranty.....I was told them were the spark plug seals? If that makes sense?

[tenkfeet]

No warranty.....I was told them were the spark plug seals? If that makes sense?

Has your blowing dip stick let oil get into the plugs?

[meatball]

No warranty.....I was told them were the spark plug seals? If that makes sense?

Has your blowing dip stick let oil get into the plugs?

I was told that wasn't possible?

[David]

Me thinks this is adding up to over filling the oil, or oil surge problems. If not, I think this going to get expensive.

[meatball]

Oh thanks!
Nah, oil level is fine, the dipstick wasn't coming free, so I applied more pressure and the O-ring snapped and popped off.....now replaced!
Apparently the spark plug seals are a common VVTLi problem?

[robin]

On the Toyota engine there is an "acrylic rubber" gasket that creates a seal between the cam cover and the cam ladder - this seal runs around the periphery of the engine as you would expect, but it also has a "peninsula" that runs around each spark plug bore (the plugs need to come out the top).

On the K this is a sheet gasket that completely covers all the oily bits; on the Toyota the cams are exposed because there is an oil spray system in the cam cover itself that bathes the cams in oil while the engine is running. This means that there is a lot of oil flying around inside this space, and if the gasket fails around the plug bores, they will fill up quickly.

I thought that the gasket and spark plug seal were a single piece, but it may be on the Elise/Celica variant of the engine they are infact two gaskets, thus "new seals" and "new gasket for cover".

The spark plugs come with compression seals anyway (the captive washer thing that sits at the top of the plug's thread), so if that's the "seal" that is being referred to, new plugs will obviously bring new seals.

Is there any explanation for why oil in this area is causing the problem you're seeing? Is the theory that the oil is causing a breakdown in the HT or control circuit?

I wouldn't replace the plug top coils until it was clear they were broken - I don't suppose they're cheap!

Cheers,
Robin

[meatball]

Your explanation sounds spot on as usual Robin.
The second last para is beyond my level of expertise though.......I was a bit fried by that time! My basic understanding is that the engine is burning some oil and the sensor reads this and says "too rich"?
I will ask my mate again and post the official answer.....
The coils will be checked before I replace them at around £70 a pop!

[robin]

Unfortunately, although you can test the coil at room temperature it's hard to test it at full chat (as I found out to my cost recently). However, I would expect either the ECU to pick up a misfire if the coil isn't working properly - certainly it would be cheaper to do a full power run on a rolling road and check engine performance and emissions than it would be to replace all those coils on spec.

Cheers,
Robin

P.S. Quite surprised that burning a tiny bit of oil makes the ECU think the engine is running rich ...

[meatball]

You are some man......that is exactly the plan!
Going to look for a rolling road through the week....if not I will improvise!
Still waiting on the update re the fault found and the error code!

[DJ]

Going to look for a rolling road through the week....if not I will improvise!

This line made me think of Ferris Beuller's Day Off

Hope you get it sorted

[steve_weegie]

Unfortunately, although you can test the coil at room temperature it's hard to test it at full chat (as I found out to my cost recently).

Dont tell me you're trying some proper tesla experiments Robin...

[robin]

No, much less exciting - on Andy's S2 we had a real problem getting the engine to run once swapping out the rotten old ECU interface board ... I tested the coils with a multi-meter the way you're meant to and they were fine, but when running on the road (or the rolling road) the engine just didn't run properly (spookily it produced about 50% power - that should have been a clue!). Anyway, swapped the coil packs for some other ones and it ran beautifully. Lesson learned ... if the coil packs fail the multi-meter test, they are gubbed; if they pass you still don't know.

In the old days or Robot Wars there was some speculation about building an EMP weapon, but it was quickly outlawed

Cheers,
Robin

[meatball]

the gaskets are seperate as the VVT system on toyota engine operates on a oil pressure related basis. therfore if the oil was diverted elsewhere then no oil pressure would build up causing no VVT.
the k- series engine is VVC. and has a mechnical rod connecting 2 camshafts together with oil pressure playing no part so 1 complete gasket is fine.

the too rich problem: the leaking seal (s) are causing a oil build up in bank 1. therefor the fuel isn't being burnt as it should which causes excess un-burnt fuel hence the too rich fault code.

[robin]

So is it burning oil, or is the oil is stopping the spark from happening? If the oil is stopping the spark is it because the oil is in the cylinder itself or because the oil is in the plug bore (i.e. outside the cylinder?). Whatever, it doesn't really matter - the oil leak should be fixed - but were it me I would like to understand why the oil leak is causing the fault code - otherwise the fault probably won't be cured

Cheers,
Robin