Hissing sound under acceleration.

[FatHead1979]

If it’s not an expensive part, personally I’d change it for peace of mind.

[Tdci-Peter]

6 hours ago, Albert27 said:

what is the official name for the sensor?

I am almost certain that is the MAP (Boost pressure) sensor. If it was broken, there would be a warning light on, as it is a critical sensor.

I can not recall if you have an ELM & Forscan, that would soon tell you if the sensor is working ok. It should read about 100kPa (1 Bar) at idle, and ramp up to about 240kPa (2.4 Bar) on full boost, which will only happen while accelerating hard. Forscan can be used in data logging mode while driving.

But if the turbo seems to be working, acceleration & max. power is ok, and there is no excess smoke, the sensor must be working adequately well. But like Damien says, it might be worth replacing if it looks physically damaged. You could also experiment then with why it does not fit in the new pipe, and if there is some way to fit it.

The turbo would not work very well with a hose not connected!

With most fans, centrifugal or axial, they tend to slow down (become more heavily loaded) when working into no pressure, ie free flow. It is when the flow is blocked or restricted that they tend to speed up. It is the air flow through the fan that they work against, and can stall and rotate more easily with insufficient flow. I have not verified this with a turbo compressor, but I doubt if it would have gone overspeed.

 

[Albert27]

7 hours ago, Tdci-Peter said:

I am almost certain that is the MAP (Boost pressure) sensor. If it was broken, there would be a warning light on, as it is a critical sensor

Could it be the Air temp sensor?  I tell you why I think that...I looked in the Haynes and identified the sensor showed on the left as you look at the manifold as the MAP sensor.  The 110ps doesn't seem to have this separate sensor on the right and mine is the 90ps version with that seemingly extra sensor.  When i looked on ECP the MAP sensor looked like the MAP pictured in haynes and the one on the left on mine.  But I couldn't find a sensor that looked like the mysterious one on the right that i've damaged! 

I do have Forscan Lite mobile app but I'm pretty sure you can run a test while driving on that as I've done it before for the EGR valve. I've asked to return the eBay part.  The angle of the second position sensor (the one on the right)  points down where as the genuine part points straight out.  This means that the bracket supporting the manifold and anti shudder valve is obstructing the hole as well as the hole not physically being big enough for the sensor.  I think I'll just ring a few dealers and get the genuine part.  Would it be worth calling a motor factors for a cheaper but OEM manifold pipe?

[TomsFocus]

I think you're right David, it's an intake air temp sensor.  I hadn't even noticed there was one post turbo on these before. 

There is one on the 110 model as well, it's just on the left behind the map sensor with a grey plug.  If you can get a part number from it, put that into fordpartsuk or mister-auto and it should give you the correct sensor.

 

[Tdci-Peter]

8 hours ago, Albert27 said:

Could it be the Air temp sensor?

Yes, I did not notice the second sensor there, either! It is usually called IAT or IAT2 in the diagnostic info (Intake Air |Temp). Often these are just thermistors, that read about 10k ohms at 25C, reducing in resistance as they get warmer. It looks like yours is still working, maybe just the supporting plastic frame is damaged, & the sensor element is ok. It is less critical then the MAP. I think it is mainly used to control the EGR, when an accurate intake flow (from pressure, air density & RPM) is needed. Though air temp may also be used to fractionally adjust the injection timing. But not all 1.6TDCIs have it.

From the circuit diagram, the 110PS non-DPF does not have this sensor, 90PS & 110PS DPF should have it. Though that information is not 100% reliable.

Pity about the hole in the wrong place / angle. Some of these parts can be a real headache to track down. Even the garages & dealers get wrong bits quite often.

[Albert27]

2 minutes ago, Tdci-Peter said:

Yes, I did not notice the second sensor there, either! It is usually called IAT or IAT2 in the diagnostic info (Intake Air |Temp). Often these are just thermistors, that read about 10k ohms at 25C, reducing in resistance as they get warmer. It looks like yours is still working, maybe just the supporting plastic frame is damaged, & the sensor element is ok. It is less critical then the MAP. I think it is mainly used to control the EGR, when an accurate intake flow (from pressure, air density & RPM) is needed. Though air temp may also be used to fractionally adjust the injection timing. But not all 1.6TDCIs have it.

From the circuit diagram, the 110PS non-DPF does not have this sensor, 90PS & 110PS DPF should have it. Though that information is not 100% reliable.

Pity about the hole in the wrong place / angle. Some of these parts can be a real headache to track down. Even the garages & dealers get wrong bits quite often.

I think you may be right, the frame definitely snapped but hopefully the sensor is ok.  Would a temp sensor like that flag up any warnings if it was damaged/broken or give any indications?

It is a shame about the eBay parts on this occasion but hey ho sometimes you get a gem other times you have to cough up and pay ford for the genuine article, £60 later (Ouch! ).  Picking it up tomorrow so should have it fitted by Monday and finally an end to the hiss!

Thanks for your help guys, as always much appreciated and very informative.  

[Tdci-Peter]

20 minutes ago, Albert27 said:

 Would a temp sensor like that flag up any warnings if it was damaged/broken or give any indications?

My IAT puts the light on with a relevant error code if un-plugged. A broken wire or sensor would do the same. A calibration error is much less likely on these, but would not give any error indication. If you can read it via a diagnostic system, it should read ambient temp with a cold engine.

Probably the biggest risk from a physically damaged sensor is that it could fall apart, and bits of it get sucked into the engine. My sensor has a rather delicate plastic frame that sticks right into the air flow.

I was looking at it the other day because I can not get any sensible readings from it via Forscan. The only IAT I could see, read 27C, cold engine and about 15C ambient. But I gave up due to lack of time (and enthusiasm, as it did not seem to be causing any problems!). But that is the 1.8. You may see two IATs on the 1.6, 1 will be pre-turbo (in the MAF), 2 will be post-turbo (your suspect).

 

[Albert27]

7 minutes ago, Tdci-Peter said:

My IAT puts the light on with a relevant error code if un-plugged. A broken wire or sensor would do the same. A calibration error is much less likely on these, but would not give any error indication. If you can read it via a diagnostic system, it should read ambient temp with a cold engine.

Probably the biggest risk from a physically damaged sensor is that it could fall apart, and bits of it get sucked into the engine. My sensor has a rather delicate plastic frame that sticks right into the air flow.

I was looking at it the other day because I can not get any sensible readings from it via Forscan. The only IAT I could see, read 27C, cold engine and about 15C ambient. But I gave up due to lack of time (and enthusiasm, as it did not seem to be causing any problems!). But that is the 1.8. You may see two IATs on the 1.6, 1 will be pre-turbo (in the MAF), 2 will be post-turbo (your suspect).

 

I think what I'll do is fit the new part and get that sorted and then plug in forscan when i get a minute and see what it shows.  From what I've seen of the sensor I broke, I think I'll be pretty safe but then as this thread has proven; I'm no expert!  

[Albert27]

Fitted the new Ford part today with no issues, car is driving great and a noticeable return of normal acceleration! Also a bit of hesitation the engine was having at certain revs seems to have gone.  Have run forscan and got the underboost DTC which I've cleared.  No other indications on the sensor although i didn't do the test on a run, just on the driveway with ignition on.   

Is there a knack to tightening/undoing torx screws?  Nearly every time i use them i have small shavings either from the torx head or the screw itself. Just worried I'm damaging my tools!

[Tdci-Peter]

4 hours ago, Albert27 said:

Is there a knack to tightening/undoing torx screws?  Nearly every time i use them i have small shavings either from the torx head or the screw itself.

I don't know of any problem in using Torx bits. It may be the bits you see are flakes of corrosion from the bolt, released by the pressure.

One thing I would do, with all old screws, but especially Torx & Allen, is to use a small screwdriver or similar, to clean out the recess in the head. Torx & Allen have blunt driver bits, that will force muck or rust into the recess, and stop full tool engagement, with risk of damaging the head. Also, as with all driver bits, put plenty of pressure inwards, forcing the bit into the recess, to prevent "camout" due to worn screw heads or bits.

Some lower quality bits may be too hard, and flakes could fracture off, you would see this damage on the bit, maybe with a magnifier. If so, discard the bit before it damages a screw head.

---

Good news about the car, if the leak was losing enough air to be audible inside, it would have affected performance and economy, especially at higher powers.

 

[TomsFocus]

I find Torx bits are usually made softer than the bolt head to avoid damaging the head.  Think I've been through 2 T30 bits and a T20 on my current kit...lifetime warranty on Halfords ones though so replaced for free each time.  

I have rounded a couple of Torx heads though, have to make sure you're totally square on the bolt head which can be awkward depending on access.  Cheaper ones may not be made to the same tight tolerances so there could be more chance of slipping with those than branded ones.

[Albert27]

8 hours ago, TomsFocus said:

I find Torx bits are usually made softer than the bolt head to avoid damaging the head.  Think I've been through 2 T30 bits and a T20 on my current kit...lifetime warranty on Halfords ones though so replaced for free each time.

I think I'll be heading the same way with my torx heads!  I have the same Halfords ones with the lifetime warranty.  I reckon I've lost the receipt though. Are they pretty easy going with swapping them?

[TomsFocus]

I bought my kit online about 4 years ago and didn't even get a receipt as far as I can remember.

Haven't had any issues swapping them so far but it might depend on your store.  They keep loose torx bits and sockets behind the counter for exactly this purpose, didn't even ask how it broke.  I once had to swap the tiny adapter, totally my fault using it for something too tight but they didn't even question it!