Thread: Provent 200 outcome after 150,000km

Originally Posted by BRADS

We have plates and egr deletes in both our hilux and cruiser and both previous hiluxes
While I'm certainly no expert at all I'm not sure your information is correct but happily to be proven wrong
The egr is only open on idle. It's never open when trying to make power.
It can't be you need make exhaust manifold pressure to create boost.

I’ve got the Denso training documents somewhere. If it’s at hand I’ll post it but it’s probably archived away somewhere. You’ll be able to find it online I expect. It’s a hard read but it explains how it all works. It will be a good few years old now, at least 16 or 17 I would think.

But no, what you said is not correct. The EGR is closed on a cold start & idle and gradually opens slightly as the engine temperature warms up. The EGR operates primarily at cruising speed on low to medium engine loads. That’s the whole point - it’s there to put some exhaust gas back into the intake manifold when the engine is not working hard. It closes under hard acceleration.

Give me a few minutes because I know I’ve got a more detailed explanation somewhere from my brother-in-law in South Africa who is very much into this kind of thing.

I have no idea of the origin of this because I’m 100% sure that my brother-in-law didn’t write it because he can barely speak English. But this neatly summarises what I learned about EGR from the LV & heavy plant guys I worked with at the mines, who were Toyota & Denso, Cat trained. They were mostly the light vehicle team so they looked after Hilux, Land Cruiser, Hino trucks and the like. But a couple of the guys in the gang were Caterpillar experts. The principles were broadly the same. To blank or not to blank your 4WD was the subject of many a camp fire debate out in the middle of nowhere.

Article:

Problems with the EGR system, like so many vehicle problems, are often caused by a lack of maintenance: diesel owners typically expect high mileages and low maintenance bills. Because owners expect their diesels to go for huge mileages without much maintenance, they don’t pay much attention to their diesel engines until something goes wrong. By then it may be too late. Also, many diesel owners resent paying to have their engine’s EGR valve replaced at a fairly early age (it can be expensive). However, faulty EGR valves can sometimes be fixed by simply cleaning them. Moreover, many EGR problems can be avoided by simply ensuring that the vehicle is maintained regularly and gets a decent blat down a highway at least once a month, with plenty of accelerating and decelerating (pottering around town at low speeds is especially bad for EGR valves).

The EGR system on this engine uses an electronically-controlled throttle plate within the inlet manifold; hence it’s name: the manifold flap. As the inlet manifold begins to soot-up, the manifold flap begins to jam. This will cause all sorts of problems (see below) Many owners have tried to remove the EGR assembly for this reason, but there are lots of fishhooks in the process. The first one is that the removal of the EGR assembly will confuse the ECU and trigger a ‘check engine’ light. There are, however, proper removal kits for those who wish to take this path. This removal kit has blanking plates for the manifold, together with a custom computer chip that fools the ECU into thinking that nothing’s changed.

There are lots of reasons for removing the EGR, and lots of reasons for not removing the EGR.

The Exhaust Gas Recirculation (EGR) valve is an anti-pollution device, aimed primarily at reducing the amount of nitrogen oxide (NOx) spewing out of the vehicle’s exhaust pipe. The engine produces nitrogen as part of the combustion process. As the temperatures inside the engine increase, this nitrogen and the oxygen in the engine’s combustion chamber can chemically combine to form nitrogen oxides. NOx reacts with sunlight to cause smog.

Exhaust Gas Recirculation works by recirculating a controlled portion of an engine’s exhaust fumes back through the engine. The EGR valve is the tap that turns the flow of exhaust gases on and off, hopefully at appropriate times. These recycled, carbon dioxide-rich exhaust fumes cool the combustion chambers within the engine. This cooling effect lowers the combustion chamber temperature. These recycled exhaust fumes also displace some of the oxygen that would otherwise be drawn into the engine from the surrounding atmosphere. Because the combustion chamber is cooler and because there’s less oxygen, less NOx is produced. Also, because the combustion chambers are cooler, the engine as a whole runs cooler. This is particularly important to the engine’s turbocharger: turbochargers (and the oil that they need for their lubrication) don’t last long if the engine is overheating.

Because the EGR’s recycled exhaust gas displaces some of the air within the combustion chamber, the engine’s efficiency is reduced. For this reason, the EGR system doesn’t operate during times of heavy acceleration. It also doesn’t operate during idle, because the presence of exhaust gases at idle tends to cause uncontrollable rough running.

EGR systems operate primarily when the vehicle is cruising under light load. Because there is less demand on the engine when the vehicle is cruising under light load, the engine can afford to temporarily lose some capacity. Also, because of the cooling effect of the EGR system, the engine can run cooler when the vehicle is cruising under light load. Because the engine is cooler, the engine’s lubricating oil is cooler as well. Cool oil lasts longer and works better than oil that has been continuously overheated. Therefore, the EGR system is important for the cool running of the engine and also in the protection of the engine oil from continuous heat.

In the real world, EGR valves often don’t work very well. What goes wrong is this: the exhaust gases from the vehicle’s engine contain much more than just carbon dioxide: they also contain dozens of chemical by-products, left behind after the fuel was burnt inside the engine. One of these by-products is a fine dust, known as particulates. This dust is mostly unburnt carbon fuel. The more efficiently the diesel engine burns its fuel, the less carbon dust is produced. However, no diesel engine works with anything like complete efficiency and, over time, the carbon dust inside the exhaust gases begins to clog up the EGR system, reducing the movement of the EGR valve. This clogged EGR valve causes the engine to run badly due to an imbalance in the fuel/air mixture. Because the engine is running badly, the fuel is not being consumed efficiently. Because the fuel is not being consumed efficiently, more carbon dust is produced. Some of this carbon dust within the exhaust gets recycled by the EGR system, clogging the EGR valve still further. The more the EGR gets clogged, the more carbon dust is produced. The more carbon dust is produced, the more the EGR valve clogs. This viscious circle continues until the EGR valve jams completely open or closed.

If the jammed EGR valve is not repaired or replaced quickly, all sorts of problems may occur. Four of the most common are rough running, high fuel consumption, turbocharger failure and, sometimes, total engine failure.

Here’s how it works:

When the engine is cruising, the EGR valve is supposed to open to allow the carbon dioxide in the exhaust to cool the combustion chamber. However, if the EGR valve jams open, exhaust fumes are being fed into the engine at all times. This can mean poor acceleration and rough running, because the excess exhaust fumes are depriving the engine of oxygen. Because there is insufficient oxygen, there’s too much fuel, so the unburnt fuel starts spewing out of the exhaust as black smoke, especially when the engine is at idle. Fuel consumption is likely to rise substantially. Also, due to a lack of oxygen (which is needed to complete the combustion process), the engine sometimes starts to misfire, sometimes seriously (this misfiring may produce an unusual metallic rattle or knocking when the engine is under load). If the engine is left in this condition for too long, the engine life will be shortened considerably. In the worst case this problem may cause melted pistons and therefore engine failure. The valves in the cylinder head may also begin to stick due to being heavily coated with carbon.

However, other really nasty problems occur when the EGR valve jams closed: without the cooling effect of the exhaust gases, the engine starts to overheat. Over time, this overheating causes the engine oil that feeds the turbocharger to break down. When the engine oil starts to break down, the bearings in the turbocharger fail. When the bearings fail, the turbocharger will fail, and replacement won’t be cheap. If the turbocharger is replaced without solving the EGR problem, the next turbocharger will also fail before too long.

It gets worse: when the engine overheats, more lubricating oil can enter the combustion chamber and the engine can start running on lubricating oil even if the diesel fuel supply is cut off. The engine may then begin to run on its own engine oil instead of diesel fuel. The driver may be unable to switch off the engine except by stalling it. Eventually, the engine sucks away all the lubricating oil and the engine disintegrates.

Originally Posted by Flyblown

I have no idea of the origin of this because I’m 100% sure that my brother-in-law didn’t write it because he can barely speak English. But this neatly summarises what I learned about EGR from the LV & heavy plant guys I worked with at the mines, who were Toyota & Denso, Cat trained. They were mostly the light vehicle team so they looked after Hilux, Land Cruiser, Hino trucks and the like. But a couple of the guys in the gang were Caterpillar experts. The principles were broadly the same. To blank or not to blank your 4WD was the subject of many a camp fire debate out in the middle of nowhere.

Article:

Problems with the EGR system, like so many vehicle problems, are often caused by a lack of maintenance: diesel owners typically expect high mileages and low maintenance bills. Because owners expect their diesels to go for huge mileages without much maintenance, they don’t pay much attention to their diesel engines until something goes wrong. By then it may be too late. Also, many diesel owners resent paying to have their engine’s EGR valve replaced at a fairly early age (it can be expensive). However, faulty EGR valves can sometimes be fixed by simply cleaning them. Moreover, many EGR problems can be avoided by simply ensuring that the vehicle is maintained regularly and gets a decent blat down a highway at least once a month, with plenty of accelerating and decelerating (pottering around town at low speeds is especially bad for EGR valves).

The EGR system on this engine uses an electronically-controlled throttle plate within the inlet manifold; hence it’s name: the manifold flap. As the inlet manifold begins to soot-up, the manifold flap begins to jam. This will cause all sorts of problems (see below) Many owners have tried to remove the EGR assembly for this reason, but there are lots of fishhooks in the process. The first one is that the removal of the EGR assembly will confuse the ECU and trigger a ‘check engine’ light. There are, however, proper removal kits for those who wish to take this path. This removal kit has blanking plates for the manifold, together with a custom computer chip that fools the ECU into thinking that nothing’s changed.

There are lots of reasons for removing the EGR, and lots of reasons for not removing the EGR.

The Exhaust Gas Recirculation (EGR) valve is an anti-pollution device, aimed primarily at reducing the amount of nitrogen oxide (NOx) spewing out of the vehicle’s exhaust pipe. The engine produces nitrogen as part of the combustion process. As the temperatures inside the engine increase, this nitrogen and the oxygen in the engine’s combustion chamber can chemically combine to form nitrogen oxides. NOx reacts with sunlight to cause smog.

Exhaust Gas Recirculation works by recirculating a controlled portion of an engine’s exhaust fumes back through the engine. The EGR valve is the tap that turns the flow of exhaust gases on and off, hopefully at appropriate times. These recycled, carbon dioxide-rich exhaust fumes cool the combustion chambers within the engine. This cooling effect lowers the combustion chamber temperature. These recycled exhaust fumes also displace some of the oxygen that would otherwise be drawn into the engine from the surrounding atmosphere. Because the combustion chamber is cooler and because there’s less oxygen, less NOx is produced. Also, because the combustion chambers are cooler, the engine as a whole runs cooler. This is particularly important to the engine’s turbocharger: turbochargers (and the oil that they need for their lubrication) don’t last long if the engine is overheating.

Because the EGR’s recycled exhaust gas displaces some of the air within the combustion chamber, the engine’s efficiency is reduced. For this reason, the EGR system doesn’t operate during times of heavy acceleration. It also doesn’t operate during idle, because the presence of exhaust gases at idle tends to cause uncontrollable rough running.

EGR systems operate primarily when the vehicle is cruising under light load. Because there is less demand on the engine when the vehicle is cruising under light load, the engine can afford to temporarily lose some capacity. Also, because of the cooling effect of the EGR system, the engine can run cooler when the vehicle is cruising under light load. Because the engine is cooler, the engine’s lubricating oil is cooler as well. Cool oil lasts longer and works better than oil that has been continuously overheated. Therefore, the EGR system is important for the cool running of the engine and also in the protection of the engine oil from continuous heat.

In the real world, EGR valves often don’t work very well. What goes wrong is this: the exhaust gases from the vehicle’s engine contain much more than just carbon dioxide: they also contain dozens of chemical by-products, left behind after the fuel was burnt inside the engine. One of these by-products is a fine dust, known as particulates. This dust is mostly unburnt carbon fuel. The more efficiently the diesel engine burns its fuel, the less carbon dust is produced. However, no diesel engine works with anything like complete efficiency and, over time, the carbon dust inside the exhaust gases begins to clog up the EGR system, reducing the movement of the EGR valve. This clogged EGR valve causes the engine to run badly due to an imbalance in the fuel/air mixture. Because the engine is running badly, the fuel is not being consumed efficiently. Because the fuel is not being consumed efficiently, more carbon dust is produced. Some of this carbon dust within the exhaust gets recycled by the EGR system, clogging the EGR valve still further. The more the EGR gets clogged, the more carbon dust is produced. The more carbon dust is produced, the more the EGR valve clogs. This viscious circle continues until the EGR valve jams completely open or closed.

If the jammed EGR valve is not repaired or replaced quickly, all sorts of problems may occur. Four of the most common are rough running, high fuel consumption, turbocharger failure and, sometimes, total engine failure.

Here’s how it works:

When the engine is cruising, the EGR valve is supposed to open to allow the carbon dioxide in the exhaust to cool the combustion chamber. However, if the EGR valve jams open, exhaust fumes are being fed into the engine at all times. This can mean poor acceleration and rough running, because the excess exhaust fumes are depriving the engine of oxygen. Because there is insufficient oxygen, there’s too much fuel, so the unburnt fuel starts spewing out of the exhaust as black smoke, especially when the engine is at idle. Fuel consumption is likely to rise substantially. Also, due to a lack of oxygen (which is needed to complete the combustion process), the engine sometimes starts to misfire, sometimes seriously (this misfiring may produce an unusual metallic rattle or knocking when the engine is under load). If the engine is left in this condition for too long, the engine life will be shortened considerably. In the worst case this problem may cause melted pistons and therefore engine failure. The valves in the cylinder head may also begin to stick due to being heavily coated with carbon.

However, other really nasty problems occur when the EGR valve jams closed: without the cooling effect of the exhaust gases, the engine starts to overheat. Over time, this overheating causes the engine oil that feeds the turbocharger to break down. When the engine oil starts to break down, the bearings in the turbocharger fail. When the bearings fail, the turbocharger will fail, and replacement won’t be cheap. If the turbocharger is replaced without solving the EGR problem, the next turbocharger will also fail before too long.

It gets worse: when the engine overheats, more lubricating oil can enter the combustion chamber and the engine can start running on lubricating oil even if the diesel fuel supply is cut off. The engine may then begin to run on its own engine oil instead of diesel fuel. The driver may be unable to switch off the engine except by stalling it. Eventually, the engine sucks away all the lubricating oil and the engine disintegrates.

Good read thanks for that
I was way out

Sent from my SM-S916B using Tapatalk

So @BRADS For me the reason I didn’t want to blank the EGR was because when I bought my Hilux in Australia, I knew that there would be many long, continuous operating hours trips at relatively light engine loads as we cruised from A to B across the outback. When we crossed the Nullarbor we would drive over 1,300km in one hit, from Kal to Penong, sometimes further.

We would be sitting at a fairly consistent 100km/h for the entire journey at a moderate engine load, monitored on the Scangauge II, so the EGR would be open pretty much the whole time. With the mileage I was doing on a new engine I was far more concerned about not screwing up the ECU’s ability to manage combustion temperature, than I was about a slightly sooty valve & intake manifold.

The article does state the intentions of the design quite well, ties in with what I have been trained on it.

What I can't correlate in my head, is the fairly large assumption that there will be long periods of time at moderate engine loadings for one and two that the engine management system needs extra help to manage engine temperature during periods where engine loads are not high and combustion temperatures are comparatively lower than at periods of high loading.

It's for me a fairly large assumption to be making that you are going to have the load cycles where the egr system will have a positive net effect on engine operation and not negative. There's been a few of those fireside conversations I've been part of where the discussion revolved around the intent of the system and the real world does not seem to really correlate with the operating conditions where it's required to be in use by the ECU.

If the engine is at high load, injectors will be operating at near full duty cycle or sequentially firing on each power stroke until the oxygen sensor cries enough, not sufficient oxygen left in the exhaust gasses to burn any more fuel which is prime conditions for NO creation (insufficient oxygen/rich burn). At this point the EGR setup will be fully closed at peak heat generating, relying fully on the engine cooling system.

Injecting what is essentially low-oxygen heated gas into the combustion system intake basically seems counter-intuitive on any consideration of straight engine operating efficiency, unless you factor in reburning I.e. modifying the chemical nature of the exhaust gasses for the reasons of climate requirements while preventing a lean-burn condition which can cause excess heat generation and poor efficiency. Maximum cooling effect is by high airflow of cool clean fresh air through the engine in conjunction with engine coolant systems, that's why we have turbos and intercoolers. The EGR system from that, works hand in hand with the other exhaust gas treatment system or systems to provide climate mitigation effects by chemically modifying the exhaust gasses.

Where this gets interesting, is the prevailing opinion by people that know this stuff is that the EGR system is designed to work in conjunction with the DPF system and cooling the combustion temps is largely driven by the need to control the DPF operating environment. A DPF 'self clean' or 'reburn' requires engine rpm/load, extra fuel and the egr valve closing supporting this opinion. Deleting the DPF without doing the EGR or vice versa could or can create the unusual operating conditions that might result in engine damage.

Of more interest, real world figures show that deleting both DPF and EGR with the appropriate retune results in slight power and torque gains, reduction in fuel burn and a cooler running engine. So, if we fit EGR/DPF for environmental reasons yet it causes more fuel to be burned to do the same work what are we gaining? Possibly the only realistic benefit is a reduction in diesel exhaust particulates, but only if you are not near a reburn event or an engine in high load operating conditions. And arguably burning more fuel creates more of what we don't want, hotter exhausts, worse pollution... Again, supporting this is the fact that virtually all testing and stats on these engines is on test tracks with vehicle at factory unloaded, not in real world conditions.

Originally Posted by Mathias

@Twodiffs there's some really good reading on the aussie patrol forum about what you describe. Old Mav on there explanes about the volume of crankcase pressure on a boosted TD42 being close to 200L per minute, which a Provent 200 is designed for. Theres pictures of a custom rocker cover vent with 25mm outlet.
I've got same truck as you but running way less boost (10psi) due to no cooler. I've got a bit of sneaky oil issue too & I think it's related to my cheap Chinese catch can. So I'm going to by pass it to see if it fixes the issue.

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Yep onto that mate, I was Twodiffs on there but changed to 1TUFGQ, I started a thread couple months ago and fortunately Oldmav is still around

He chimed in with some really good info hence why the Safari is away getting the Provent replumbed now.

Originally Posted by Twodiffs

Yep onto that mate, I was Twodiffs on there but changed to 1TUFGQ, I started a thread couple months ago and fortunately Oldmav is still around

He chimed in with some really good info hence why the Safari is away getting the Provent replumbed now.

Would like to see a snap of the new breather attachment on rocker cover if poss, when done. I'll probably do same

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Will do, I should have it back in next few days.