Technical Map Sensor

[Adam1984]

Hello,

So I am now on 63500 miles and had the spark plugs and HT leads done.

I am sure I read with short journeys that the MAP sensor is going to need replacing, is this the case, any brand to get, what about the VVT sensor, worth doing too?

Lambda Sensor?

Thanks.

 

[Herts Hillhopper]

No.

On the diesels, the pressure and airflow sensors can eventually soot up (and be fixed by cleaning - my 120,000 mile diesel Landrover still has all the original sensors and is ‘just fine’. ). Petrols - not considered a service item - and certainly not at that low mileage.

Your car is working. The plugs that came out looked new so didn’t need changing. Just leave it alone .

(Although checking the tyre pressures as the weather cools - which will lower the pressures - would be the one thing you might consider now and again)

 

[Adam1984]

No.

On the diesels, the pressure and airflow sensors can eventually soot up (and be fixed by cleaning - my 120,000 mile diesel Landrover still has all the original sensors and is ‘just fine’. ). Petrols - not considered a service item - and certainly not at that low mileage.

Your car is working. The plugs that came out looked new so didn’t need changing. Just leave it alone .

(Although checking the tyre pressures as the weather cools - which will lower the pressures - would be the one thing you might consider now and again)

Thank you.
I will leave the car as it is. There is still just one problem am having with the car and that is the grinding noise am getting from the brakes. Maybe there is some metal on metal.

Or could the brake pad/disc brand also be causing it. With cheaper ones being used?

 

[Herts Hillhopper]

‘Cheaper’ brands (for most car parts) are just as good as more expensive ones - they just cost less. Like Aldi baked beans vs ‘genuine’ Heinz ones.

Worn brakes squeal. Brakes that don’t see enough use (short journeys round town) tend to ‘scrape’ as a rusty crust forms around the edge of the discs. A regular longer, faster drive with plenty of rapid slowing usually fixes that. If they were nearing end of life the MoT would have flagged it.

 

[rmjbn1]

I think
MAP
VVT solenoid
Throttle body
Inlet manifold
Are worth cleaning every once in a while. I spray carb/brake cleaner on the MAP, on a cloth and wipe out the TB and manifold every year.
But they don't need replacing if they're not faulty

 

[Adam1984]

I think
MAP
VVT solenoid
Throttle body
Inlet manifold
Are worth cleaning every once in a while. I spray carb/brake cleaner on the MAP, on a cloth and wipe out the TB and manifold every year.
But they don't need replacing if they're not faulty

Thank you

What is the inlet manifold and how is that best to be cleaned? All the rest done with electrical cleaner?

 

[Pugglt Auld Jock]

Thank you

What is the inlet manifold and how is that best to be cleaned? All the rest done with electrical cleaner?

I agree with cleaning the MAP sensor. I give mine a good spraying with carb/brake/sensor cleaner at the yearly service - let it dry thoroughly before fitting it back to manifold. I started doing this some years ago when she was not driving quite as I felt she should. There was mainly a slight hesitation and "holding back" when accelerating briskly (largish throttle openings) I'd done all the usual stuff, plugs, HT leads, etc with no change and thought to myself, "Might be the MAP as it directly affects fueling?" so I removed it, which is very easy to do, and found the end was absolutely soaked in engine oil. Sprayed it with cleaner and sprayed cleaner into the hole it fits into. I've never cleaned inside the manifold but I do keep the throttle body clean around the butterfly. Mine doesn't have a VVT solenoid as it's the older 60 hp engine, but I would agree that removing it and cleaning it's screen filter is something I'd do if I ever own one with. These screen filters are something I've often thought about in relation to turbo oil supply. Some, maybe most? have a fine filter in the feed to the turbo bearings and it's one reason why I'm very keen on regular oil changes on any engine which has a turbo. Of course turbos stress their oil anyway so regular oil changes are "de rigueur"
I didn't say above that cleaning the MAP made an absolute world of difference and completely restored normal running. I've done it yearly since then and no longer have any problems.

 

[Adam1984]

I agree with cleaning the MAP sensor. I give mine a good spraying with carb/brake/sensor cleaner at the yearly service - let it dry thoroughly before fitting it back to manifold. I started doing this some years ago when she was not driving quite as I felt she should. There was mainly a slight hesitation and "holding back" when accelerating briskly (largish throttle openings) I'd done all the usual stuff, plugs, HT leads, etc with no change and thought to myself, "Might be the MAP as it directly affects fueling?" so I removed it, which is very easy to do, and found the end was absolutely soaked in engine oil. Sprayed it with cleaner and sprayed cleaner into the hole it fits into. I've never cleaned inside the manifold but I do keep the throttle body clean around the butterfly. Mine doesn't have a VVT solenoid as it's the older 60 hp engine, but I would agree that removing it and cleaning it's screen filter is something I'd do if I ever own one with. These screen filters are something I've often thought about in relation to turbo oil supply. Some, maybe most? have a fine filter in the feed to the turbo bearings and it's one reason why I'm very keen on regular oil changes on any engine which has a turbo. Of course turbos stress their oil anyway so regular oil changes are "de rigueur"
I didn't say above that cleaning the MAP made an absolute world of difference and completely restored normal running. I've done it yearly since then and no longer have any problems.

Thank you to everyone for the support.

Can I get to the Map sensor without taking the air filter off?

I have read not to use brake cleaner on this part as it's best to use electrical cleaner .

Is it easy to clean?

 

[Panda IIs]

Thank you to everyone for the support.

Can I get to the Map sensor without taking the air filter off?

I have read not to use brake cleaner on this part as it's best to use electrical cleaner .

Is it easy to clean?

Carb cleaner; check the label on the can for suitability.

 

[Pugglt Auld Jock]

Thank you to everyone for the support.

Can I get to the Map sensor without taking the air filter off?

I have read not to use brake cleaner on this part as it's best to use electrical cleaner .

Is it easy to clean?

I do use sensor cleaner most of the time as my factor always seems to have one brand or another on special offer. Also I wouldn't use brake cleaner or carb cleaner on a hot wire type MAF sensor as I'd worry the cleaner might leave deposits behind which might bake onto the sensor wire/surface. Map sensors don't get hot so I'm happy to use carb/brake cleaner on them, but always let them evaporate dry before trying to start the engine. (Carb cleaner is apparently more aggressive than brake cleaner?) At this moment I've got a can of this: https://www.liqui-moly.com/en/gb/ai...jgs_d3CEwKt3cP29WX96z7gn1mbH_LxOAK04-OUP#4066 Which seems to do the job very nicely.

Edit. I clean mine when doing a service so have the filter housing off anyway. I guess you can get to it ok with the filter in place? but it's so easy to remove I'd just do that. Easy to clean? hell yes, just spray the cleaner all over and into the end of the sensor - general advice is not to physically touch it though, as in trying to poke it with a cotton bud or piece of cloth. Just flood it with the jet of cleaner.

 

[Adam1984]

I do use sensor cleaner most of the time as my factor always seems to have one brand or another on special offer. Also I wouldn't use brake cleaner or carb cleaner on a hot wire type MAF sensor as I'd worry the cleaner might leave deposits behind which might bake onto the sensor wire/surface. Map sensors don't get hot so I'm happy to use carb/brake cleaner on them, but always let them evaporate dry before trying to start the engine. (Carb cleaner is apparently more aggressive than brake cleaner?) At this moment I've got a can of this: https://www.liqui-moly.com/en/gb/ai...jgs_d3CEwKt3cP29WX96z7gn1mbH_LxOAK04-OUP#4066 Which seems to do the job very nicely.

Edit. I clean mine when doing a service so have the filter housing off anyway. I guess you can get to it ok with the filter in place? but it's so easy to remove I'd just do that. Easy to clean? hell yes, just spray the cleaner all over and into the end of the sensor - general advice is not to physically touch it though, as in trying to poke it with a cotton bud or piece of cloth. Just flood it with the jet of cleaner.

This is my map sensor I finally managed to get it out.

Now cleaned and just drying for 15 mins.

Did it look bad?

 

[Adam1984]

This is my map sensor I finally managed to get it out.

Now cleaned and just drying for 15 mins.

Did it look bad?

And this is now. And connected back.

Next to do the same with the VVT solenoid.

 

[rmjbn1]

Well done
Looks pretty oily.

Which makes me think there might be a puddle of oil sitting in the bottom of the inlet manifold? (Which is where the MAP sits)

Sorry I don't know how easy it is to clean out on yours, my 60hp 1.2 has the TB on top of the manifold. I remove the TB and push a cloth in to soak up any oily puddles

 

[Adam1984]

Well done
Looks pretty oily.

Which makes me think there might be a puddle of oil sitting in the bottom of the inlet manifold?

Sorry I don't know how easy it is to clean out on yours, my 60hp 1.2 has the TB on top of the manifold. I remove the TB and push a cloth in to soak up any oily puddles

This what you mean?

 

[rmjbn1]

That's the butterfly in the throttle body.

I would spray some cleaner on a cloth and wipe it clean.

Undoing the four torx screws and removing the TB should give you access to clean inside the black plastic manifold, but I'm not certain, maybe someone else could confirm

 

[Herts Hillhopper]

Brakes. I did disc and pad on Ruby earlier this year. A corner of the tin back plate got bent and was touching the disc. Awful noise less wgen turning. There is very little clearancce. It was quite hard to spot, but easy to fix.

I think this reply was intended to be in a different thread (this one…
https://www.fiatforum.com/threads/2...ar-brake-disc-replacement.518993/post-4840917 )

 

[Herts Hillhopper]

The sensor and manifold will tend to have an oily film as that’s where the crankcase breather ‘vents’ to, so that any oil vapour is burnt in the engine rather than released into the atmosphere as ‘pure oil’. It’s not uncommon to see them like this.

Although not listed as a service action, it’s a good idea to spray carb cleaner on the sensor now and again (every couple of years maybe) - although it is presumably designed to cope with an oil coating since it will always be in an oily mist?

I would stay away from trying to do anything with the manifold as there’s a risk of doing more harm than good (eg displaced debris getting into the engine)

 

[Panda IIs]

I think this reply was intended to be in a different thread (this one…
https://www.fiatforum.com/threads/2...ar-brake-disc-replacement.518993/post-4840917 )

Yes I thought so! @The Panda Nut noted - thanks but not the back plate

 

[Pugglt Auld Jock]

The sensor and manifold will tend to have an oily film as that’s where the crankcase breather ‘vents’ to, so that any oil vapour is burnt in the engine rather than released into the atmosphere as ‘pure oil’. It’s not uncommon to see them like this.

Although not listed as a service action, it’s a good idea to spray carb cleaner on the sensor now and again (every couple of years maybe) - although it is presumably designed to cope with an oil coating since it will always be in an oily mist?

I would stay away from trying to do anything with the manifold as there’s a risk of doing more harm than good (eg displaced debris getting into the engine)

I think you've nailed it here. The sensor seems to tolerate a certain amount of oil mist contamination but when the covering gets too heavy it impacts on performance - typically with the driver experiencing hesitation and lack of pulling power when the throttle is initially opened. Because it's such an easy thing to do I just make cleaning it with a spray of cleaner part of my yearly maintenance plan, along with oil and filter change etc. I have never tried cleaning out the inlet manifold as I think it's a waste of time. The breather is going to quite quickly reintroduce some oily deposits due to the very nature of how it works - Must say I didn't consider that solid deposits might be disturbed by cleaning. I'm a big fan of NOT using engine flush products for this very reason (ie possible blocking of pickup strainers etc.)

At one time I considered rerouting the breather so it vented to atmosphere thus avoiding the problem altogether. However I think this is actually illegal? and likely to fail MOT if noticed by the tester? So, when I found that a periodic quick clean of the sensor made the problem go away I just left things as they are.

Talking about rerouting crankcase breathers. From what I've read, and logical deduction, I believe a great deal of the carbon fouling - but not necessarily all of it (EGR gasses for instance) - which causes so much of the inlet tract carbon fouling on direct injection petrol engines, can be directly attributed to crankcase gasses being directed into the inlet tract. Which is then exacerbated by feeding exhaust gasses into the same system. When I learned that my previous car 2016 1.0 litre Ibiza (EA 211 engine with 95hp) didn't "do" EGR I actually started looking at how I might achieve a direct to atmosphere vent which wasn't too obvious. However The issues I had with the gearbox etc overtook me before I got round to it and I sold her. I don't know if the Scala "does" EGR and actually, I don't know, now my annual mileage is much reduced, whether I can be bothered! I'd rather spend my time with my old lawnmowers etc (got a very early 2 stroke Flymo with the JLO engine (which, in my opinion was a much better engine than the much more common Tecumseh) and upgrading my Home Cinema

 

[Adam1984]

Thank you to all the advice you have given me.

So since cleaning the VVT and map sensor. My MPG has gone down by so much, I was getting about 44, but now only getting 39.8 to 40.1 is this poor? And maybe causing another issue somewhere else?