Jump to content
The mkiv Supra Owners Club

Still smoking, still no solution


Jake
 Share

Recommended Posts

:banghead:

Somebody please tell me what to do with my car.

('00 VVTi with PHR Stage One GT60 single turbo)

 

(Previously discussed in this thread)

 

It's smoking like hell on the over-run. In this thread Jarrett from PowerHouse Racing reckons it's not the turbo and it's probably valve stem seals, rings, or PCV system that are causing the problem.

 

The compression seems OK to me (145psi on each cylinder). Surely the stem seals can't be the problem on a 50,000 mile car?

I don't really understand the PCV system but from what I've read I don't think it would cause smoke on the over-run, would it?

 

What can I do to diagnose the problem?

 

 

Thanks for any help.

Link to comment
Share on other sites

As you know I'm no expert, but leaking stem seals would show themsleves on cold startup or after a long idle. Does it smoke when firing up or after a throttle blip after 10mins+ idle?

 

If not then I can't see how the stem seals could be at fault.

 

Is it puffing blue smoke under boost at all? What about off-boost?

Link to comment
Share on other sites

No smoke on startup, cold or hot.

It only seems to do it when I close the throttle while driving along.

I think I'm right in saying that it only does it when I'm on some boost (even very low boost) and then close the throttle. It's possible that it does it if I'm cruising off-boost and then take my off but I haven't noticed it.

(Smoke from the car you're driving is hard to see unless it's pretty bad)

 

BTW

It's blue smoke so must be oil. It's using lots of oil too.

Link to comment
Share on other sites

Hi Jake

 

Lets look at this logically.

 

I don't remember you saying that the car has always done this, so if it's suddenly started doing it, its unlikely to be valve stem seals. They don't "blow" as such, just gradually wear. You start off noticing a small amount of smoke and it gradually gets worse over the course of time. Valve stem seal problems are more pronounced with the throttle closed, on the overrun, due to the oil being drawn into the cylinders by the high vacuum.

 

For the PCV system to be causing major problems, it really needs to be completely blocked. You can test this by running the engine and removing the oil filler cap. If you get a hiss as all the pressure is released, then you may have crankcase ventilation problems. Alternatively you can temporarily disconnect on of the breather hoses on the cam cover, and as long as the car will run, just take it for a short drive. If it still smokes you know its not excess crankcase pressure, because you're venting to atmosphere.

Be mindful of the fact that you may get some oil out of the cam covers whilst driving.

 

Maybe a leakdown test would help diagnose whether the rings are OK, but it sounds more like oil control rings, than compression rings, so it may not show up the problem.

 

As for the turbo, oil seal problems with turbos normally manifest themselves after the car has been sitting idling for a while and you blip the throttle. Have you tried doing that?

 

Otherwise you're probably down to trying to beg, borrow or steal a turbo from someone else to try on your car.

 

I must admit to having a nasty feeling that it is probably turbo related. I'd probably do the easy checks first to try and eliminate everything else, but it wouldn't surprise me if the turbo ended up being the culprit.

 

It's either that or something nasty internal :( Didn't this happen just after a mapping session?

 

Good luck with it Jake.

If you want to bounce any ideas around feel free to give me a shout.

Link to comment
Share on other sites

Sounds like rings to me, has it ever run for any length of time at all with a bad map in it, allowing it to run rich? I haven't time to go through all the old posts, sorry. If it has been smokey rich I'd say therein lies your answer. Rebore and pistons and rings I'm afraid. If you are very lucky it might hone and new rings could fix it.

Link to comment
Share on other sites

I would say rings as well going from the smoking scenarios you said Jake. I also think your 145psi is a little on the low side.

 

Why not get a proper leakdown test done, that should tell you a lot.

 

He has a thicker HG Dan, although I don't understand the thinking behind that with a small single.

Jake, who did the first rebuild? Do you know why it let go then?

Link to comment
Share on other sites

I don't remember you saying that the car has always done this, so if it's suddenly started doing it, its unlikely to be valve stem seals.
My Mrs reckons it's always done it a bit. She says it does it on gear changes and when accelerating.

 

For the PCV system to be causing major problems, it really needs to be completely blocked.
Hmmm. Does the fact that my exhaust side cam cover is vented to atmosphere means that it's not a PCV problem?

 

Maybe a leakdown test would help diagnose whether the rings are OK, but it sounds more like oil control rings, than compression rings, so it may not show up the problem.
I've just been ringing round but can't find anyone local to do a leakdown test. Like you say though, even if it passes it could still be the oil control rings.

I must admit to having a nasty feeling that it is probably turbo related.
To be honest I'm hoping it is the turbo. Anything to do with piston rings is going to be major work and expense.

Didn't this happen just after a mapping session?
Well it's got worse since then. I never noticed it smoking before buy like I said above, my Mrs recons it's always done it.
Link to comment
Share on other sites

Sounds like rings to me, has it ever run for any length of time at all with a bad map in it, allowing it to run rich?

If it has been smokey rich I'd say therein lies your answer. Rebore and pistons and rings I'm afraid. If you are very lucky it might hone and new rings could fix it.

It was running a bit rich before I had it mapped recently, but not madly rich. The engine rebuild it had about a year ago was, according to the previous owner, because the e-Manage Blue it used to have fitted was over-fuelling badly and had caused bore-wash.

 

Jake' date=' who did the first rebuild? Do you know why it let go then?[/quote']Rebuild was by Tuning Japanese because of borewash. I don't think the problems back then are related to this though.
Link to comment
Share on other sites

I think Phoenix can do the leak down test for you, not sure how close they are to you though

 

You could try a drive with the oil filler cap "kind of" off. This would give you plenty breathing ability (ruling out the PCV being shagged) but I don't know how much misty oil you might get blown out of there. Also you'd want to be careful of anything getting in there. What about fixing a piece of gauze over the hole and go for a drive without the cap. I'm not convinced it's the PCV but it would be a nice easy fix.

 

I'm just throwing ideas out to help rule things out here.....

 

Did you speak to TurboTechnics or Turbodynamics at all? Assuming it is a Garrett core then these guys should be able to repair or at least check it..

Link to comment
Share on other sites

Jake

If your cam cover vents to atmosphere it's not going to be a PCV problem.

 

I'm not going to go up against CW and his vast knowledge ;) I'm a fool, but not that much of one :D

 

If its always done it then it "could" be valve stem seals, but if you're putting out a smokescreen like James Bond, then again its unlikely.

 

I hope it's the turbo, you really don't want to have to pull the engine out for yet another rebuild :(

 

I suppose you don't know if the engine was run in with mineral oil or not?

Link to comment
Share on other sites

The engine had only done about 350 since the rebuild when I got the car. I don't know what oil was in it at the time.

 

 

This afternoon I took the car out to warm it up before trying a few things to diagnose the PCV but the damn thing isn't smoking now. Once it was warmed up I did a few motorway pulls and let it over-run loads of times but as far as I can tell it's fine at the moment. :think:

 

Looking at the oil on the dipstick, it's quite black and I'm not sure if it smells of petrol. If there was petrol in the fuel that would be a sure sign the rings are shot, wouldn't it?

Isn't there somebody here who can get oil samples analysed?

Link to comment
Share on other sites

I'd send the turbo to a good rebuiders for a check over for a start. If it didn't have a rebore with oversize pistons I'd budget for just that, I'm afraid. How long did it run un mapped after the rebuild, in all honesty???? You can knacker rings in an hour with a very rich setting. Are you 100% sure it now runs a sensible fuel map? Has it got datalogging enabled? If not get it unlocked and run a wideband and post me some traces.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.