JTS running very rich

[josh18]

Thanks Bazz. I take it a new inlet manifold would be a pretty easy job, and valve guide seals could be done when i do the timing belt. As far as compression is concerned, what values should I expect, and is there a special way to do it on this car due to the electronic throttle body? Number one plug has been wet with oil but Im sure this was due to a leaky cam cover gasket, which i replaced the other day.
Im still confused as to why the smoke seems very black when i always thought oil smoke was supposed to be blue. Though it makes sense it it's oil smoke due to how much oil it uses.
Realistically, how much chance is there of it being a simpler fix like the manifold gasket or stem seals, rather than bad rings? I guess a comp test will confirm it.
Cheers

[johnl]

OPERATION IN CLOSED STAGE
When the closed stage is required (idle speed and maximum power zone), the solenoid is de-energized, so the slide valve in the base mount of the solenoid prevents the oil from reaching the variator.
In this case the timing of the inlet valves remains unchanged (closed).

OPERATION IN OPEN STAGE
When the open stage is required (medium rpm with high torque). The solenoid is energized, thus opening the slide valve allowing oil to enter the Variator and forcing it to rotate clockwise which transmits rotation to the camshaft, thus varying by 25° engine the timing of the inlet valves.

The Variator operation is disabled below 2500-3000rpm, the idea being to give better economy at more "conservative" driving styles. Hence the reason why 2.0 TS & JTS seem doughy and unresponsive below 3000rpm, drop a gear, put the boot in and it kicks in and "away we go!"

There is an old Alfa Romeo saying, "Fun starts at 3000!"   

Baz, you are correct, and my memory is faulty. Off the top of my head I was recalling (from nearly a year ago) the idle becoming a lot worse when I disconnected the solenoid (very 'hunty', as is typical with a lot of valve overlap). But thinking back more carefully what I actually did was to artificially energise the solenoid at idle (testing). It was this that caused the idle to worsen, i.e. energising the solenoid at idle, which means the variator must be inactive at idle / low rpm.

Considering this, I do wonder why the variator tends to rattle for a couple of seconds at start up, until general oil pressure builds and it stops rattling. Surely if the variator is not activated (at idle / low rpm, and again above 5000 rpm) because it is isolated from oil pressure because the solenoid is not 'on', then the variator should not rattle at start up? Yet it does, and only stops when general pressure builds, which implies that even when the solenoid is 'de-energised' the variator must still be seeing at least some pressure at idle / low rpm. Doesn't make sense to me. Confused...

Is it possible that the solenoid is staged, i.e. with at least two 'settings', one allowing X pressure to reach the variator (to prevent rattling), and another allowing X+ pressure to reach it, enough to overcome resistance and advance inlet timing?

Yes, the TS engine is quite doughy below 3000 rpm. At least with my car it also behaves differently when performing heel/toe down shifts. The engine response from a throttle 'blip' is far less predictable below 3000 rpm, making it much harder to achieve clean heel/toe shifts at lower rpm. It would be interesting to see what happens with this if the solenoid were to be artificially switched 'on' 'permanently'...

Regards,
John.

[johnl]

Thanks Bazz. I take it a new inlet manifold would be a pretty easy job, and valve guide seals could be done when i do the timing belt. As far as compression is concerned, what values should I expect, and is there a special way to do it on this car due to the electronic throttle body? Number one plug has been wet with oil but Im sure this was due to a leaky cam cover gasket, which i replaced the other day.
Im still confused as to why the smoke seems very black when i always thought oil smoke was supposed to be blue. Though it makes sense it it's oil smoke due to how much oil it uses.
Realistically, how much chance is there of it being a simpler fix like the manifold gasket or stem seals, rather than bad rings? I guess a comp test will confirm it.
Cheers

Josh,
Replacing valve guides and seals is a head off job.

I doubt the inlet manifold has anything to do with your problem (been wrong before...). It wouldn't hurt to check that all the manifold nuts are tight (or even still there...).

It's not a bad idea to check compression, keeping in mind that an engine with good compression can still leak oil past the rings (in some cases the extra oil around the compression rings can actually improve compression test numbers). Ideally a compression check should be done with the butterfly wide open, as this will maximise compression numbers measured. However, the most important thing with compression testing isn't the maximum numbers (unless they are all quite low), but the relative numbers cylinder to cylinder. They should all be fairly close to each other. Since checking compression with a closed butterfly will affect all cylinders equally (restricting airflow into the cylinders), it won't make much difference to the relative numbers you'll see (though the absolute numbers will be somewhat lower).

Having said this, unless I'm missing something you could do the compression check with the injector wires disconnected and the throttle pedal held to the floor, which will prevent fuel being injected during the testing. If fuel is injected it will be expelled from the spark plug orifices (all plugs should be out for compression testing so the engine can spin freely), which is at least a fire hazard (don't ask me how I know...).

I'm not quite with Baz on this. He seems convinced your smoke is oil smoke, and while much of it probably is considering your oil consumption, I think the blackness does also point to a rich AFR. My experience is that oil smoke is bluish gray, quite a different colour to fuel smoke. I think Baz is quite right to be concerned at your engines' oil consumption, it does seem quite excessive to me.

At some stage soon I think you'll need to be thinking about the points where oil can enter the cylinders, i.e. rings, valve guides and seals. Another entry point is though crankcase breathers, you might want to have a look at at the hose where the crankcase gasses are vented into the inlet manifold. If this is very oily then this may be where much of the oil is getting in. If it is don't get too exited about any easy fix, oil usually spews from this hose because of excessive crankcase pressure, which is caused by compression and particularly combustion pressures escaping past the compression rings into the crankcase...

(edit to add; there is a 'fix' of sorts for this, crankcase pressure can be vented into a catch tank (to stop oil spillage) rather than into the manifold, but, this is illegal to do...)

I'd still be having a look at the 02 sensors. The pre cat ones are used for measuring 02, the post cat ones are so the ECU can monitor the main cat function, and have no influence on AFR (at least with most engines as I understand it, I don't know the JTS, but I doubt it's different). The problem is that replacing 02 sensors in an engine that is burning a lot of oil might fix the problem in the short term, but continued oil burning may well wreck the new sensors fairly quickly...

From what you say you don't really know if your #1 plug is oily because of oil entering the cylinder, or simply that oil flowed over it when you pulled it out (from the oil in the plug well). You need to clean the plug well of oil, then drive the car for a while before having another look at the plug (hopefully the leak is slow enough that the well won't just fill with oil again).

Regards,
John.

[bazzbazz]

Ok, by telling me that #1 spark plug is oily you have just confirmed that is most likely oil leaking through the inlet manifold galleries. And for you and John, here is a photo of what happens when it leaks.
Also this is the easiest to check, just take the inlet manifold off.

Oil going down the plug tube from leaking camshaft cover wont foul the plug as the plug is sealed against the head, its just the tube that fills with oil.

If I am wrong and its all clean, then it is most likely valve seals. And John, if it was from being OVER FUELLED, why are all the other spark plugs nice and light brown? If it is being over fuelled to the point of leaving oily residue all over the rear bumper I think you'd find the plugs to be in similar condition.



Baz

[johnl]

It seems Josh can't say whether the plug was oily before he pulled it, because of the oil sitting in the plug well that may have just run over the plug when it was extracted. This needs to be clarified.

You have a point, if the engine is consistently running rich then the plugs should show it. But, if the engine only runs rich at wider throttle openings then they might not, because the majority of running might be lean enough to clear the plug of a sooty build up. It's still possible that #1 cylinder is indeed running rich, enough to cause black smoke. If so then the other cylinders are most likely running at least somewhat lean due to the one very rich cylinder affecting overall 02 content in the exhaust gasses and so corrupting the signal to the ECU.

If only one cylinder is running rich (if it is), then I think there would definitely be a problem with the injector to that cylinder, i.e failing to fully close, or maybe sticky, so it can't respond fast enough to the required pulse width (this would keep it effectively open longer than it should be), though, I would expect this to affect AFR at all throttle openings.

If excessive oil is getting into #1 (quite possible), it would create grey smoke. If the cylinder is very rich then any grey smoke can be hidden by the black smoke. If the valve seals are toast, then I would expect to see more smoke at start up after the car had been sitting for some time (enough time for oil to drain past the seal, down the guide and into the cylinder, or to sit on top of a closed valve). This is a classic symptom of worn seals / guides, as is a puff of oil smoke as you get on throttle after the engine has been on the over run with a closed throttle (very high manifold vacuum 'sucking' oil into the ports through the stem / guide clearances, then burnt as soon as the throttle is opened). After a short while running the oil smoke from worn stem seals tends to diminish. If on the other hand the engine smokes more consistently then it's more likely to be oil leaking past the piston rings.

The oil in the plug well isn't good, but not a big deal, just messy. It won't cause a loss of spark at the plug because oil is a very poor conductor of electricity. My Accord used to leak a heap of oil into the plug wells (before I fixed it), and I can't say I ever noticed any misfires. It is indeed conceivable for an 'oil bath' to prevent a misfire, say by effectively insulating an eroded hole in the plug lead where a spark would otherwise be free to jump to the side of the plug tube...

Regards,
John.

[bazzbazz]

Here is a guide for doing a compression test. Values for your car should be between 200 - 250psi

http://www.freeasestudyguides.com/compression-test-wet.html

Don't forget to check the Crankcase High Speed Breather Valve (PCV Valve), its the one going from the top back right of your Cam Cover to just behind the Throttle Body. It can get clogged up which will cause high oil usage too. So check that first, it's the easiest. Just be careful removing the plastic valve cover behind the Throttle Body, old plastic is brittle. Give the valve cover a good clean as well as the little golf tee valve inside, make sure the spring is not broken.

Then compression check, to disable fuel and ignition, remove the corresponding relays in front of the battery.

Then check for variator duct leak in the manifold gasket.

These are the easiest in order.

Baz

[josh18]

Thanks guys, you both have some really good points and info. I think like John said, the oil on number one plug came from the oil in the pug well saturating the plug when i took it out. I have replaced the gasket so it should be dry in there when i check it again so i will have a better idea of where oil if any is from.
The way john described worn valve seals was pretty much my understanding of it too- smoke on acceleration after the over run due to high vacuum.
Thanks Bazz for the tip on the breathers etc. I will re read all the posts and go through all the easier things this weekend.
There is a pretty good chance I am seeing blue smoke in the mirror and mistaking it as black, seeing the plugs are not fouled (I have a lucas injected Triumph as my toy, so I know what fouled plugs look like), but as John said it only seems rich some of the time. Fuel economy is still pretty good though too.
Cheers guys

[johnl]

Baz is right to suggest checking the PCV. Any blockage in the breather system means that crankcase pressure can't easily vent, so the pressure rises and rises to the point that one of the easiest pathways to relieve the pressure is into the cylinder void past the piston rings. This happens when the cylinder pressures are low, mostly on the induction stroke (when cylinder pressures are actually negative), and oil is carried with the crankcase gasses into the cylinder.

Another symptom often associated with a blocked breather is a multitude of small oil leaks, because the pressure can be high enough to force oil past any weak gasket or other seals (might explain a leaky cam cover gasket...?).

High crankcase pressure also reduces performance appreciably, because it takes energy for the pistons to descend against the higher than usual crankcase pressures. This is a debatable point, because it can be argued that the pressure also pushes against the underside of the simultaneously ascending pistons, so it's a zero sum game, i.e. no net increase in power required to move the pistons. What I do know from experience with blocked breathers on a couple of cars I have owned, declogging resulted in a quite noticeable improvement in performance...

Regards,
John.

[johnl]

Forgot to mention that high crankcase pressures can also force oil from the case into the cylinders via the valve guides. I suspect less will tend to flow through worn guides / seals than will flow past worn rings, all else being equal.

More thoughts on crankcase breather systems, as per my understanding of them;

Most systems use two hoses between the case and the induction system. One hose (A) is connected to the induction at some point between the butterfly valve and the ports (i.e. somewhere on the inlet manifold), and is exposed to high vacuum at small throttle openings, and lesser vacuum at larger openings. The PCV is part of this circuit, and restricts hose A gas flow into the manifold at higher manifold vacuum, and increasing flow as manifold vacuum decreases. The idea is that the 'air leak' into the manifold created by hose A is always flowing a more or less consistent quantity of gasses, which can be adequately accounted for by the ECU or the carburettor jetting (i.e. more relative pressure through a smaller orifice at high manifold vacuum, less relative pressure through a larger orifice at lower vacuum, hopefully amounting to a similar gas quantity flowed in the differing conditions). If the PCV were not there, then this would be an uncontrolled air leak.

Hose A 'sucks' fairly hard at small throttle openings (idle / low rpm cruise), when blow-by gas production is low and at relatively low pressure in the case. At larger throttle openings the manifold vacuum reduces and blow-by and case pressure increase, but a lesser %age of the total pressure and gas escapes through hose A because of the lower manifold vacuum and the restriction created by the PCV (even fully open it's a fairly small valve area relative to the quantity of blow-by gasses being created).

The second hose (B) is connected to the induction pipe before the throttle body (or carburettor), and never sees the degree of vacuum that hose A sees at small throttle openings. At idle / low rpm, hose B allows the crankcase to actually be ventilated with filtered fresh air, not just for the pressure to be relieved (hose A sucks gas from the crankcase as hose B allows fresh air to flow in, replacing harmful gasses, including water vapour). This helps to scavenge harmful gaseous chemicals from the crankcase (products of combustion, many of which are acidic), which otherwise would be absorbed into the oil, and increase the rate of oil contamination.

When throttle opening is high, cylinder pressures increase dramatically, and thus so does the blow-by gas (I think both max out at the max torque rpm, when cylinder pressures are greatest). A lesser %age  of the crankcase pressure / gas now escapes through hose A, but due to the increase in blow-by gasses the flow through hose B reverses, so now much more blow-by gas flows though hose B, which is then 'sucked' into the engine through the throttle body (or carburettor). This is aided by the decrease in manifold vacuum at larger throttle openings, and by the concurrent increase in vacuum before the butterfly (where hose B connects).

Normally not much oil will be carried with the blow-by gas through hose B (or hose A for that matter). However, if blow-by is quite substantially more than it should be, then quite a lot of oil can be carried through both hoses with the gasses. If an engine tends to get a filthy throttle body, then this is likely to be the problem, i.e. excessive blow-by. The worst example of this I've experienced was the Fiat Twin Cam engine in the Nota Sportsman I used to own (google it if you're wondering). The engine generally ran well, but really it needed new rings, blow-by was excessive.

If this car was driven at about 110kmh for a long stretch then blow-by pressure could steadily increase until oil would spray from hose B into the air filter canister, get sucked in through the carbs and create a smokescreen behind the car. Then, at lower speeds the car would run rough for a while until the plugs cleared, and if you had to come to a stop it could stall and be somewhat reluctant to restart.

Regards,
John.

[josh18]

Ok guys, compression test done and all were around 215 to 220 dry and all about 250 to 250 wet (three squirts of oil).
PCV hoses seem to be clear but I couldn't find the golf tee valve in the cam cover. It looks to be just a baffle setup, glued and bolted in. It didnt seem like it would come out without breaking it. I dont have any other leaks anywhere though so I doubt it is blocked and pressurizing the crank case. I am going to try running with the PCV hose off though (into a can) and see if it runs different and if it is expelling anything. That pipe was cracked previously and it didn't run any different so I think it should run ok with out it (am I wrong?).
I did notice though that while I thought the cams are in good nick, they are stuffed. I'll post pics later but one of quite a few lobe pairs are worn pretty severely. At first it looked like it was meant to be like that as it is smooth but they are all different. One exhaust lobe is almost gone! i don't know if this could have anything to do with my smoke issues but it needs to be fixed.
I haven't looked at the manifold gasket yet but will put a pic up of the week old plugs. They all look pretty similar, some slightly darker than the others and all black around just the base.
So going by my comression results is it safe to say that the rings might be ok and it's valve guide seals or is it too hard to tell without a strip down? I'm prepared to either fix or change the head (timing belt needs doing soon anyway) but am not up for a rebuild. Also am I looking at stuffed bearings with all the cam metal floating around in the oil? It has always seemed particle free, hopefully the filter has done it's job!
To tell you the truth we have been thinking about selling this car on but everything else we look at is so boring! So I am trying to decide whether or not to put some more money into it and keep it.
Cheers, pics later

[josh18]

So I put some long hoses onto the cam cover vent and wrapped them up in a white rag. I blocked off the respective lines to the TB.
I noticed the vent puts out a bit of pressure so I guess there is a bit of blow by the rings but all engines do this, I don't know how much though. So on my drive It still blows smoke, but on inspection of the rag afterwards it was still clean, so I don't think a blocked PCV or venting oil into the inlet is an issue.
So that leaves me with rings, valve stem seals or the manifold gasket leak.
So from my limited knowledge, if it was rings I would have thought the compression would be down more, valve guides like John said, would be more likely after idling or after decelerating in gear. So next port of call will be to inspect that gasket. Looking at the set up, it looks like a pretty painful job to get the manifold off- is there an easy way?
One thing I noticed on this drive is that the smoke seems to start as the engine makes a slight change in tone, maybe the variator kicking in or out? It seems to be around 5000 rpm, so when it disengages?

Here are some pics of the plugs and cams. Looking back at the plugs, number 1 is definitely darker. Let me know what you think.
Cheers

[josh18]

pics

[V AR 164]

Haven't read the whole thread, so excuse me if I have said things others have said previously.

Plug no.1 definately is darker. Also if you have a look at the washer on the plug itself, it is covered in oil. One of my V6 does this and I'm 99% sure it's because of the valve stem seals. However, as you mentioned, it should blow blue/white smoke, not black.

Have you tried a good old Italian tune up? (A good thrashing, I mean a REALLY GOOD thrashing). You will be surprised as to how much better the car will run afterwards.

Also, I would HIGHLY recommend to check out the Coolant Temp Sensor and its wiring, I have just spent the last 6 months tracking down rich running myself and after changing everything, it turned out to the the coolant temp sensor connector.
To test it out, pull off the plug while the car is running. It should make the computer think the car is very cold (or hot, I don't quite remember) and in doing this it will over fuel (or under fuel) to compensate. You should hear a difference in idle, if not I would investigate it further.

Hope this helps, Andrew.

[josh18]

Thanks Andrew.
I had thought about coolant temp sensor but assumed it worked as the gauge works, but I don't know if it uses the same wiring or not. Or even if it uses the same sensor!
It's a strange issue though as it only seems to over fuel (or whatever the smoke is) above 4-5000 revs. Seems fine the rest of the time.

[johnl]

The plugs look just a bit sooty to me rather than oily, though it's hard to really tell from photos. One is a bit darker on the outer electrode, but not hugely. It's the porcelain colour that is more indicative, and those all look rather similar, and reasonably OK.

Your compression numbers seem healthy, suspiciously high even on the 'dry' test (oily rings can give a higher psi on a compression test). I'd expect numbers under 200 psi, though the JTS static compression ratio is fairly high, so maybe it's fine.

I'd be surprised if your problem has to do with a leaky manifold gasket. This would normally induce a lean condition, at least in the cylinder most affected. It would also tend to cause a poor idle.

Here's a trick to roughly test how much 'suction' you're getting from the inlet manifold side of the breather. Take off the oil filler cap while the engine is idling. Hold your hand just above the orifice, and you'll feel a pulsating air movement (you can take your hand away now).

Next, take a sheet of paper and slowly lower it onto the filler orifice. As the paper gets near the orifice it will at first be blown upward by the air pulsations, but as it gets very close it should suddenly get 'sucked' onto the orifice and stay there. It is being sucked onto the orifice by the low pressure created by the manifold vacuum. If not then you may have an issue, either the breather isn't working properly or the amount of blow-by gasses are too great for the breather to cope with.

Even though the pulsations make it feel (i.e. with the hand) like there is a lot of pressure in the crankcase, it's an illusion. With the cap off, blow-by gas comes out, air goes in, the fact that the paper gets sucked onto the orifice once it's close enough demonstrates that the air going in exceeds the gas coming out. The pulsating air from within the crankcase isn't caused by the blow-by gasses, but by the motion of the pistons moving up and down, moving gas rather violently as they do so (all engines do this, more noticeably the fewer cylinders there are, so with say a V12 it's likely to be less pronounced).

Now, with the paper sucked on, if you rev the engine the manifold vacuum will reduce and the blow-by will increase, and the paper will be blown off the filler orifice. This doesn't really tell you much, other than demonstrate the principal.

If that's not of much help, I hope it's at least somewhat interesting...

Regards,
John.