Air Flow Sensor/Snorkel Drain Hole??

[Peteyen86]

EDIT: Its the air temp sensor, not flow sensor, that's why it seemed to do nothing when removed. New question. It had a drop of excess sealant on the tip of it, i cleaned it off with some turps, could this effect/damage a temp sensor? Hopefully not!

Im mechanically minded, know nothing about electronics..lol


Hey guys.

Had my snorkel installed today on my 2006 D22 (ZD30). I used the YD25 setup like other guys, and as you will know, you need to drill a new hole in the air duct for the 'air sensor' to fit.

Well, i turned up a little early to pick up the Nav, they were still working on it. Once finished i drove 20 minutes home, no problems what so ever. Seemed to rev up a little faster in boost with the snorkel. Probably just imagining that.

Anyhow, got home and popped the bonnet to check the job out. All looked fine apart from the air sensor just hanging there

In the hurry to finish up, and with the non standard install, they forgot to drill the new hole and re install the sensor. Not to big of problem as i did it myself tonight.

Just wondering why the ute still run fine, didnt miss a beat, with the air sensor not even in the flow, just hanging under the bonnet?? Thought i read on one of the post that if the sensor gets dirty it can lead to all sorts of problems? Or is this a different sensor im thinking of? Whats the go?

First photo shows the new hole needed in the air duct for the sensor. 2nd photo is for question 2.



Question 2:

The new yd25 air duct as seen in the photo has a drain hole in the bottom of it, isn't it meant to be a totally sealed unit? Guess the water that gets sucked in when it rains needs to drain somewhere? or am i missing something...lol

Photos are not of my Nav either.

Cheers

Pete

 

[RustyNav09]

I'm pretty sure its meant to be sealed I mite be wrong. I never noticed a whole when I installed mine.

 

[Peteyen86]

mmm i thought so to, but the duct kinda slopes down to the hole also, so if any moister is in there it runs out.

EDIT:

Alright, did some research. Drain hole is needed. If you dont have a pre-cleaner you are bound to get a little water in through the snorkel (eg, really heavy rain, car wash) so thats what the hole is for. Few threads on a patrol forum.

Anyone got an answer for the sensor question.

Cheers

Pete

 

[RustyNav09]

I don't get any water in my airbox anyway when its raining. I'm pretty sure there is no hole in it. I was thinking it come out at the foam filter thing at the connection to the airbox and that fitting.

 

[Peteyen86]

The hole would only be about 2-3mm diameter at most id say. Dont know, maybe somebody else will chime in.

 

[Old.Tony]

The hole is, as you rightly point out, needed to allow water to drain out of there. When you are wading through deep water, you should have a wading bra attached to the front of the vehicle and you should NOT stop. This creates a bow wave and prevents water from filling the engine bay, which in turn prevents water from getting into that hole.

If you need to fully seal that up (like some people have done), you need to ensure that the air intake at the top of the snorkel faces down and away from the inrush created by forward movement to prevent any water getting in at all.

The sensor should be fine. It will be a bi-metal sensor encased in a ceramic-like housing (like a resistor) and should handle being cleaned without difficulty. I wouldn't use a strong solvent on it, but it's not an easy-to-kill item so I'd not worry too much. A CONSULT-II plugged into your OBD port can read the numbers coming from it (so can a bluetooth OBD with software like Ian Hawkins' "Torque" application that I am using in my car). This will allow you to test it and feel confident that it's working reasonably well - it only has to be roughly accurate (within a few degrees is fine).

 

[Peteyen86]

The hole is, as you rightly point out, needed to allow water to drain out of there. When you are wading through deep water, you should have a wading bra attached to the front of the vehicle and you should NOT stop. This creates a bow wave and prevents water from filling the engine bay, which in turn prevents water from getting into that hole.

If you need to fully seal that up (like some people have done), you need to ensure that the air intake at the top of the snorkel faces down and away from the inrush created by forward movement to prevent any water getting in at all.

The sensor should be fine. It will be a bi-metal sensor encased in a ceramic-like housing (like a resistor) and should handle being cleaned without difficulty. I wouldn't use a strong solvent on it, but it's not an easy-to-kill item so I'd not worry too much. A CONSULT-II plugged into your OBD port can read the numbers coming from it (so can a bluetooth OBD with software like Ian Hawkins' "Torque" application that I am using in my car). This will allow you to test it and feel confident that it's working reasonably well - it only has to be roughly accurate (within a few degrees is fine).

Thanks mate, thats great. Answered eveything with that post.

So the old trick people have been using covering the snorkel to see if their car stalls may not be worth it then! If you have drain holes gussing it will struggle to stall.


Cheers Pete

 

[Dave]

I filled the hole in mine with Silicon.

The engine hasn't Hydrauliced yet.

Just drill a hole for the air temp sensor.

Its easy.

 

[Old.Tony]

With small gaps in the intake, you should still be able to stall the engine.

Diesels require a phenomenal amount of air. Every 2 revolutions of the motor they suck in their entire capacity, so at idle (say 800rpm) on a 2488cc engine it has to draw in 995.2 litres of air every minute (16 litres a second). I'll go out and check that my MAF sensor is in agreement with my calculations ... back in a sec.

My Navara idles at about 750rpm (give or take about 30rpm) according to data from the ECU. At these revs, it's varying between almost 14g/s and 18g/s of air (that's what the MAF sensor is reporting - grams per second, I assume). I think it should be (750/2)*2.488/60 = 15.55 litres per second. Air weighs 1.204grams per litre at 20C (at sea level), so my 15.55 litres per second should be 18.7g/s - my calculations are roughly right, give or take errors in the MAF sensor, and my ability to see MAF data on one screen and RPM data on the other.

So - requiring THAT much air means that if you DO block the snorkel's intake, if the tube is MOSTLY sealed, the engine will starve anyway and stall. The small gaps are definitely not enough to allow enough air into the engine.

This also means that if you have a snorkel and it DOES NOT stall when you cover the inlet, it must have some large gaps in it somewhere!

 

[fzrr]

I sealed the small hole up when i sealed the rest of the snorkel with sikaflex.

Am I asking for trouble when it rains??

 

[Old.Tony]

I suppose it's possible. Water enters with nowhere to go but the airbox and the intake - it would only be a matter of time before it found its way into the turbocharger and from there into the engine. The big worry is getting it in a large gulp. The engine can handle ingesting water a drop at a time - for goodness' sake, they actually promote water injection because it "steam cleans your pistons and valves!!!" - here's one sample page that discusses it.

If your airbox gets full of water as it will if it's sealed with no means of escape, then hitting a bump or a dip in the road will cause a large amount of water to slosh into the intake, be sucked up by the turbo and jetted into the inlet manifold where it flash-boils inside the head, destroying it.

Personally, I'd put the hole back and get a wading bra.

 

[joffo81]

pre-cleaner seal?

With small gaps in the intake, you should still be able to stall the engine.

Diesels require a phenomenal amount of air. Every 2 revolutions of the motor they suck in their entire capacity, so at idle (say 800rpm) on a 2488cc engine it has to draw in 995.2 litres of air every minute (16 litres a second). I'll go out and check that my MAF sensor is in agreement with my calculations ... back in a sec.

My Navara idles at about 750rpm (give or take about 30rpm) according to data from the ECU. At these revs, it's varying between almost 14g/s and 18g/s of air (that's what the MAF sensor is reporting - grams per second, I assume). I think it should be (750/2)*2.488/60 = 15.55 litres per second. Air weighs 1.204grams per litre at 20C (at sea level), so my 15.55 litres per second should be 18.7g/s - my calculations are roughly right, give or take errors in the MAF sensor, and my ability to see MAF data on one screen and RPM data on the other.

So - requiring THAT much air means that if you DO block the snorkel's intake, if the tube is MOSTLY sealed, the engine will starve anyway and stall. The small gaps are definitely not enough to allow enough air into the engine.

This also means that if you have a snorkel and it DOES NOT stall when you cover the inlet, it must have some large gaps in it somewhere!

I just had an airtec snorkel fitted and pulled the ram off and blocked the top as you suggested when I arrived home. The engine doesn't stall. Sikaflex was used in the snorkel pipe joins (with a hose clamp of course). The pre-clener is still installed. Could the valve on the bottom of the pre-cleaner be allowing air in when I block the top of the snorkel? Should I seal that rubber valve?

Any help/advice would be appreciated as I dont really understand the function of the pre-cleaner.

Joffo

 

[Old.Tony]

I just had an airtec snorkel fitted and pulled the ram off and blocked the top as you suggested when I arrived home. The engine doesn't stall. Sikaflex was used in the snorkel pipe joins (with a hose clamp of course). The pre-clener is still installed. Could the valve on the bottom of the pre-cleaner be allowing air in when I block the top of the snorkel? Should I seal that rubber valve?

Any help/advice would be appreciated as I dont really understand the function of the pre-cleaner.

Joffo

I notice in my Airtec snorkel that there's a join as the pipe passes through the wall that I could NOT sikaflex. I can grab the air filter and pull it away from the guard, and stick a finger in the gap.

Mine's a D40 - doesn't have a precleaner and I don't follow why the D22 has one - but I'd suggest that if you have sealed that thing up fairly tight it has to be that valve. Dave might be able to shed some more light on it, but your D22 will be sucking the same volume of air as my D40 - and it's a lot!

 

[joffo81]

Thanks Tony. I'm currently sourcing the YD25 duct (from Nizzbits) to bypass the precleaner and therefore minimise number of joins and therefore potential leaks. I will definitely have a close look at the join through the wall that you mentioned. I'm still hoping that even with some minor leaks and provided I don't actually stop the nav in deep water then air will follow the path of least resistance which will be from the top of the snorkel, rather tham sucking water.

 

[Old.Tony]

Use a wading bra as well. It not only creates a bow wave and discourages water from entering the engine bay too much, but it also protects the radiator/aircon condensor/intercooler etc from stray debris in the water that you can't see.

 

[RustyNav09]

Also on the wading bra thing. I'm not sure how expensive they are for the actual branded ones, but a cheap Bunnings tarp and rope will do the same job.

Goodluck