Black smoke from engine + turbo pressure sensor?? Anyone identify this picure sensor?

[nige2009]

Hi, my Hilux has some black smoke when I rev hard in neutral or when the gears are changing (noticed when I was following my brother driving it).

I took the air filter off today and found that there is a sensor that was not attached. Could this be the reason for the black smoke problem? I'm putting the air filter back on tomorrow so won't know for sure until I've cleaned it all and got a new filter.

The engine also seems to be sucking in loads of air, is this to do with the unconnected sensor.

I've read that it might be the turbo pressure sensor.

Pics below...

Any info?

Thanks,
Nigel

Sensor pic



Sensor pic2



Back top of filter casing

[Albannach]

Could be. More likely to be either the EGR or something.

Have you any fault codes showing?

[BUSHWHACKER]

Thats the air flow sensor, it monitors the incoming airflow to the engine.
It just pushes into that rubber grommet in the filter housing.

The turbo pressure sensor is on the inner wing next to the airfilter housing and has two small diameter rubber hoses attatched.

[nige2009]

no fault codes showing or anything...

What does this sensor do though? Is it for the turbo pressure? If so how would it effect the running with it disconnected?

Cheers,
Nigel

[nige2009]

Thats the air flow sensor, it monitors the incoming airflow to the engine.

How would this effect the engine with it disconnected and could it cause the black smoke by putting the mixture out?

Nige

[GRASSMAN]

How would this effect the engine with it disconnected and could it cause the black smoke by putting the mixture out?

Nige

I allways thought that was the air temp sensor,
(it's not a flow meter) it could be fooling the ECU
to over fuel, hence the black smoke. Put plenty of
injector cleaner in next time you fill it up, and drive
it hard for a while, hope this helps.
BTW looks like a 3L is it?

Gman.

[Albannach]

How would this effect the engine with it disconnected and could it cause the black smoke by putting the mixture out?

Nige

Not really, diesel engines aren't as air sensitive as petrol engines. The MAF is more an emmissions thing.

Diesels will always smoke a bit, especially accelarating. Drive the truck really hard for a few miles, see if that helps. EGR could be gubbed, or dribbling injectors, or a split hose somewhere.

[jaky cakes]

Yup - air temp sensor. doesn't have much effect on the combustion - although if removed - unfiltered air will be allowed to enter through mounting oriface.
Surfs do emit quite a bit of black smoke during hard acceleration - it's due to the EGR valve mixing a bit of exhaust gas with incoming fresh air to "mute" or cool the combustion a bit to reduce NOx emmisions (Japan emmisions test - not UK).
It's possibly fair to say you are concerned about the smoke due to the fact this is the first time you have seen it - as you were driving behind your own truck. try blocking your EGR valve to see if it makes a difference.
Some info (taken from this forum)....

Exhaust gas recirculation (EGR) systems were introduced in the early '70s to reduce an exhaust emission that was not being cleaned by the other smog controls. Oxides of nitrogen (NOx) are formed when temperatures in the combustion chamber get too hot. At 2500 degrees Fahrenheit or hotter, the nitrogen and oxygen in the combustion chamber can chemically combine to form nitrous oxides, which, when combined with hydrocarbons (HCs) and the presence of sunlight, produces an ugly haze in our skies known commonly as smog.
So basically it re-circulates some of the exhaust gases back in to the block to reduce NOx. It says in doing this it reduces the operating temperature of the block. There are many articles written on this topic. Some written by the Green/environment people who advocate you should never disconnect the EGR because of the detrimental effects it has on your engine, of course they would, nothing to do with the environment of course.
Some by Profs’s of motor mechanics, who don't deny in disconnecting the valve it raises the NOx levels released to atmosphere (our MOT laws in England don't test for NOx). They also claim that lowering the operating temperature is not a bad thing except the re-circulated gases cause hot spots and on cast heads that’s not good. The re-circulated gases are reintroduced into the block on one side, so cooling that area not the far side of the engine, one side hotter than the other.
The other down side of the EGR is, in reintroducing the gases back in to the engine, this will place an even greater demand on engine oil performance through increased soot generation and acid levels. So you need to make sure regular oil changes are strictly adhered to.
The EGR also comes with another downside slight loss of power and decreased MPG.
The very early valves (like on the early surfs) were single diaphragm valves that open on positive pressure (some open on negative pressure) these early valves entailed a mass of vacuum hoses within the engine bay. They were not that reliable, hoses can rot, split, the diaphragm within the valve can perish, become perforated. All this leads to a none or poorly operational valve.
This system had many problems. It would often open to much, which caused a hesitation on acceleration as massive amounts of re-circulated exhaust hit the combustion chamber. The peak temperature NOx is produced at only occurs when the engine is under full load, not all the time so with older style valves it re-circulated all the time.
The newer valves are controlled by solenoids, so control the recirculation better only reintroducing the gases when the engine is under full load. So are more reliable don't effect performance so much or the MPG.
I have disconnected my EGR. I personally noticed more low down torque on my surf and better MPG. Yes my head has cracked 1 year after I got the motor and 10 months after disconnecting the EGR.
There are some who's heads have cracked and have never disconnected the EGR.
After replacing my head I reconnected the EGR for three weeks. Its disconnected again, couldn't stand the smoke it throws out the exhaust, the less grunt on acceleration and the worse MPG.
I hope this answers your question with an unbiased opinion, there are the greens who write articles on the EGR saying how great it is and mechanics who write articles saying the early valves were poor.
That’s the info; you make up your own mind.
i just blanked mine off this morning and noticed the difference immediately
more power at the low end and absolutely no black smoke at all even when i first started it
Exhaust Gas Recirculating Valves
What are they? What do they do? How do they fail??
EGR Valves have been around for a long time. Way back in 1972 GM used them in an attempt to reduce emissions of oxides of nitrogen (NOx) which were a major cause of air pollution, mainly photochemical smog, that kind of smog which is formed when strong sunlight shines down on the exhaust gasses we puke out of our tailpipes by the billions of cubic feet a day.

A short chemistry lesson is in order here. It was discovered way back when, that high combustion chamber peak temperatures (the really short duration high temperatures near the end of the combustion process) caused oxygen and nitrogen to combine chemically and form these oxides of nitrogen mentioned above. Most of the anti-pollution devices of the day did a pretty good job of reducing the other bad by-products of combustion, namely excessive hydrocarbons and carbon monoxide, however they tended to induce the formation of oxides of nitrogen. Something had to be done else we would all die of smog diseases.

The automotive engineers figured that they needed to do something to lower the peak combustion temperatures which only occurred under certain high load driving conditions. They figured they could do so at the expense of power and fuel economy but what the heck, ya can't have everything! If they could only add something to the combustion chamber that would act like sort of a fire extinguisher to cool the combustion temperatures that would do it.

So they invented a way to allow some very inert gas to get back into the combustion chamber only when needed. They needed a source of this gas - it wasn't air, cuz that contains oxygen and nitrogen which caused the problem in the first place. So they chose carbon dioxide. Where to get a supply of carbon dioxide . . . ??? Hmmmm, how about the exhaust system? That is mainly carbon dioxide and water (plus a zillion other noxious chemicals) Suppose we allow some of the exhaust gas to get back into the intake manifold under strict control and only when we need it? That would cool the combustion chamber and prevent the formation of the NoX. Maybe we should call it recirculated exhaust gas (REG??). But a guy named Reginald voted no cuz he didn't want his name associated with a car part, so they called it exhaust gas recirculation (EGR) since there was nobody around with that name.

Now we understand why it is there. And we understand what it does. So what can go wrong with it and what are the symptoms??

It's really pretty simple - it can be open when it isn't supposed to be, or it can be closed when it is supposed to be open. Not rocket science, but it is science. If it is open when it is not supposed to be open, at idle for instance, It will act like one monster vacuum leak and the engine will not idle or will idle really roughly. If it doesn't open when it is supposed to open you will probably experience a symptom of "pinging" or "knocking" since the combustion chamber temperature will be higher than normal (one of the main causes of pinging in an engine).

[BUSHWHACKER]

I allways thought that was the air temp sensor,
(it's not a flow meter) it could be fooling the ECU
to over fuel, hence the black smoke. Put plenty of
injector cleaner in next time you fill it up, and drive
it hard for a while, hope this helps.
BTW looks like a 3L is it?

Gman.

Oops, yeah I meant air temp sensor.

All my vehicles are petrol, thats my excuse anyway.

[nige2009]

Put plenty of
injector cleaner in next time you fill it up, and drive
it hard for a while, hope this helps.
BTW looks like a 3L is it? Gman.

Cheers, and it is a 3L 95 model surf.

[nige2009]

Yup - air temp sensor. doesn't have much effect on the combustion - although if removed - unfiltered air will be allowed to enter through mounting oriface.
Surfs do emit quite a bit of black smoke during hard acceleration - it's due to the EGR valve mixing a bit of exhaust gas with incoming fresh air to "mute" or cool the combustion a bit to reduce NOx emmisions (Japan emmisions test - not UK).
It's possibly fair to say you are concerned about the smoke due to the fact this is the first time you have seen it - as you were driving behind your own truck. try blocking your EGR valve to see if it makes a difference.

Thanks, I will look into this more...

cheers...

[potif]

I used to have a fair amount of black smoke coming from my 2.4. Disabled egr , changed air and fuel filters - no change, fitted performance air filter,tried many bottles of various additives (redex etc)- not much difference. Eventually got a set of recon injectors from diesel Bob and now have no black smoke and regularly get 24mpg as opposed to the 21 I was betting before.
I don't have a pocket for my air temp sensor since I fitted the performance air filter straight onto the turbo intake, so have fixed it to the pipework on the throttle body as this is the hottest point. Theory is that the computer will think that the air is at 70+ degrees and will lean out the mixture to compensate. Don't know if it makes that much difference but certainly does no harm.