How to change a map sensor on a mk2 Focus ST

A&E motorsport MAP sensor -
www.aemotorspo...
Sub count at the time of this video going live - 497
Any questions, let me know in the comments or follow me on insta and message me there mastersmods
Tracks in the vid -
Cosmo - beat is sick

[@Mastersfix]

Great vid. I'm liking the walkthrough 🙌

[@bravofoxable]

This is a good tip, very well done

[@mastersmods]

Always happy to help

[@slyfox186]

Last time 7 years ago my MAP sensor failed, the Symtoms were flickering instrument cluster lights including the turbo pod gauge lighting, fitting new map sensor fixed it, so odd but there you go.

[@debbiebeaton3771]

Great video buddy 👍

[@mastersmods]

Thanks deb, happy to helo

[@slyfox186]

I'm low on boost. Running stock, only boosts to 1/4 but should be 1/2 on gauge. If I run a higher tune it only boosts to 1/2 but should be 3/4 on gauge. Any ideas, maybe boost solenoid, map or maf? Thanks.

[@mastersmods]

@slyfox186 could be all or any one of those mate unfortunately

[@slyfox186]

@mastersmods Pain to diagnose! MAF is reading 3.5 g/s Dont think its Boost solenoid as boost levels change on different maps and boost is completely absent if plug Disconnected. MAP, I have no idea how to try and diagnose that. Checked for Vacuum leaks spraying brake cleaner on joints hoses. Might delete the symposer I've heard they cause problems.

[@mastersmods]

@slyfox186 yea they can leak boost pressure

[@slyfox186]

Changed pierburg BOOST SOLENOID which didn't work, then changed Bosch MAP sensor which actually worked 🥳 and now back to normal running and boost. This is the 2nd MAP sensor I've changed during 15 year ownership. Conclude its the internal electronics that must fail on these MAPS as cleaning them makes no difference whatsoever. My advice would be anyone with boost issues and jerking acceleration change the MAP first.

[@mastersmods]

@slyfox186 glad you've sorted it buddy

[@Beardchanics]

Good how to video!

[@mastersmods]

Thanks mate. Gone back to the roots for a quick one 😊

[@Yodaracing1]

Good video mate I hate map sensors 😂

[@mastersmods]

Cheers dude. Do ya, I never knew 😂

[@bradjoseph1623]

What was the reason for you changing this sensor? I think a persistent issue I'm having with my ST is caused by a faulty MAP sensor, but would like a second opinion

[@mastersmods]

Hi mate. The MAP sensor helps control boost basically. It talks to the ecu along with the MAF and boost solenoid to measure all things boost related such as pressure made and air coming in. Which I think then the ecu decides how to adjust things to keep the car running well

[@mastersmods]

Also the power was fading fast after 4k, which it doesn't feel like it is now but can't confirm that until I can get back to the rollers to see

[@bradjoseph1623]

I've replaced the MAP sensor in mine since writing this comment and it's solved my issue 👌

[@mastersmods]

@@bradjoseph1623 that's good news pal 👍🏼

[@markkirkbride9]

@@bradjoseph1623 what issue were you having mate?

[@kfzvokimk2246]

Really good help in the Videos 💯💪🏼

[@mastersmods]

That's what I like to see

[@markbishop4098]

@Ash, what were the symptoms of a bad MAP sensor? Why did you change it?

[@mastersmods]

I was down on boost. There's things to change when you are. Boost solenoid, MAF and MAP. Usually in that order. Other symptoms are rough idle and poor running conditions. What are you experiencing mate?

[@markbishop4098]

I get FULL boost when only half throttle applied... (intermittently) as sometimes on full throttle acceleration it sometimes "bogs down" and sounds restricted/held back?? Lift off throttle and reapply and away we go again.??? Bloody puzzling mate.. (hope all is going well after your op mate? 👌)

[@mastersmods]

@@markbishop4098 what have you done or changed so far? I'm getting there mate thank you, shouldn't be long now

[@markbishop4098]

@@mastersmods I've changed to RS plugs, K&N air filter, changed MAS sensor, Turbo boost valve for new Turbosmart one, Recirc valve, (again turbo smart) I've also made and used a smoke tester to check vacuum leaks.. Driving me friggin mad.. (oh and its now "popping and banging" ALOT? Running rich?? 🤔 and really really thirsty??)

[@mastersmods]

@@markbishop4098 try changing the MAP sensor then mate as that sounds a lot like how mine did

[@subarupaul1995]

Hi I have a 2006 ST Focus , the boost gauge on top of dash only goes to a ¼ instead of ½ way , would you say it could be MAP or Boost Solenoid ?

[@mastersmods]

I'd start with boost solenoid tbh, that's usually the culprit 👍

[@subarupaul1995]

@@mastersmods thank you , would that also mean it's not getting full boost or just giving a wrong reading at gauge , I think I might replace MAP Sensor as well , just as an added maintenance

[@mastersmods]

@@subarupaul1995 would be good practice I guess mate. I'm sure AEmotorsport sell a collection of boost solenoid, maf and map sensor as a package

[@davidmalone8868]

Hi mate. Is there a trick to getting to the screw that holds the sensor in place, just tried and didn’t have enough space with my big hands even tried taking grill and air scoop off 🤷🏻‍♂️

[@mastersmods]

Not that I can remember mate 🤔 if I remember rightly, it wasn't the easiest to get to but was definitely do able

[@classicpvchomeimprovements593]

Hi mate, great vid. have you got a link to that box covering your filter

[@mastersmods]

Cheers pal. I made them mate, I've still got the stuff to do them if you required one

[@classicpvchomeimprovements593]

@@mastersmods yes please mate, what is the cost, does it fix to the frame or something ?

[@mastersmods]

@@classicpvchomeimprovements593 do you want to message me on Instagram so we can discuss colours and cost ect?

[@gavb85]

Hi mate I’m getting code p0111 intake air temp sensor problem will the be the map sensor and would it cause my engine fan to run soon as start car up with the AC off

[@mastersmods]

More likely to be the MAF mate rather than the MAP

[@gavb85]

@@mastersmods hi mate changed map sensor and eml has stayed off and engine fan has stayed off so it worked

[@mastersmods]

@@gavb85 ah sweet, that's great news fair play 👍

[@williN57]

My ST has the full boost, but the intake air temperatur is like the ambient temperature. Do you think that the map is broken?

[@mastersmods]

Nah mate I'd say it's fine. Being close to ambient is good going

[@Emilio-madridista]

hello, I have the same engine and I get the engine failure p2178 looking in google says system too rich off idle bank 1, can the problem come from this sensor? Thank you.

[@kenmurphy4317]

Hi I am having a strange issue with my st3.every now and then when you accelerate generally off a roundabout the esp warn on dash illuminates.then the car reali struggles to move.boost is very low.and sometimes when you lift off throttle the boost gauges reaches 1 bar.its alway only ever gone to mid way on dial.

[@mastersmods]

I'd say start with boost solenoid mate

[@johnfitzpatrick9994]

Great video 👍, what's the sensor for? Yea I know I'm thick 😂

[@neil_st6073]

TBF a lot of people don't know what they do. I believe it measures air pressure in the intake manifold, which along with various readings from other sensors, helps the ECU calculate air/fuel ratios, ignition timing etc. Car runs rich or crap if it's faulty for example.

[@mastersmods]

Great question. Being the idiot I am, I forgot to mention anything useful 😂 the MAP sensor stands for manifold absolute pressure. It basically helps tell the ecu whats going on with the boost pressure. The MAF, MAP and boost solenoid all communicate with each other and the ecu to work out the differences and variables needed to keep the car running well. The MAP sensor is often over looked when trying to diognose boost problems

[@johnfitzpatrick9994]

@@neil_st6073 Thanks for your insight really helpful 👍👍

[@johnfitzpatrick9994]

@@mastersmods Hi Ash, thanks for explaining (along with Neil_ST) very helpful and clear. I'd heard about MAF sensors but not MAP so that's now on my list of things to attend to, you're a 🌟 👍👍

[@mastersmods]

@@johnfitzpatrick9994 no worries mate. It's something I overlooked as well but when there's a boost issue I think it'd be best to replace all 3 sensors at once. MAF, MAP and boost solenoid. But it comes down to budget and what's been changed before I suppose

[@deanopatchino]

Great video mate, did you have any fault codes logged?? I've got p0111 intake air temp fault on mine, seems to be overfueling and a slight missfire. Think It could be map sensor??

[@mastersmods]

I didn't have any codes mate no. I'd changed the boost solenoid and the MAF prior, I didn't think of the MAP sensor until someone suggested it.

[@deanopatchino]

Thanks for the reply mate think I'll try map first 👍 been enjoying the vids keep them coming mate

[@mastersmods]

@@deanopatchino thanks pal really appreciate it. I like to upload every Fri evening if I can

[@carlbriley]

Did you sort yours out Dean? i've had the same issue. i get full 1.2 bar boost but when it gets to 4k revs it hesitates.

[@deanopatchino]

@@carlbriley no mate cars now dead loosing compression and sound like something rattling in head 😂

[@tr1cky967]

Can anyone help me with my problem? My car dont boost all the way it just goes to the middle and only sometimes all the way but not so often. I have replaced the boost solenoid but didnt help..

[@mastersmods]

Map or maf sensor I would say. I've got a brand new bosch map sensor I can send you if you want?

[@tr1cky967]

@@mastersmods oh didnt see ur reply sorry! I have now changed the map sensor too and still no difference and the car gives 0 fault codes..

[@craigforecast9168]

@@mastersmods do you still have it?? Il buy it, I recently got a new one but it damaged and the guys saying it was fine when he sent it 😭 Also when you changed your RV did your stock one fail?? I’m getting a weird hoover kinda noise on lite acceleration.. ordered a new RV, I’ve watched your video like 5 times so I’m ready to go at it lol

[@mastersmods]

@@craigforecast9168 yes mate I've still got the map sensor and still got the after market RV. I don't think I've got the standard one tho

[@craigforecast9168]

@@mastersmods I’ve got the upgraded RV came yesterday.. just issues with the map sensor.. any chance I can grab that?

[@mrkirk4944]

My ST mk2 is poorly, poor idle, rough at lower revs, good at high revs. Changed everything from MAF to plugs, to O2 sensor, but it's looking like it could be my MAP sensor. Did you have any idle probs before you installed your MAP ?

[@mastersmods]

I didn't mate no. Have you checked your oil filter housing for any leaks? I've read that can cause rough idle and running issues too

[@mrkirk4944]

@@mastersmods I have done almost everything I can think of. RS Spark Plugs, Oil change, Oil filter, new Ford Bosch MAF filter, my CAIS gen 2 air intake system was completely removed, then all put back together to make sure all jubilee clips were tight, smoke test done in the engine bay, new alternator - mine was actually knackered, new O2 pre-cat Lambda sensor. My garage had the car up on the ramps and we both went round with torches looking for oil leaks, couldn't see anything. The car feels like it's running lean, almost like if you pulled away in 1st gear with the handbrake still up, that kind of feeling. The engine light comes on at times, and my OBD fault reader tells me that the "O2 sensor is slow to respond", despite a new O2 sensor. The after cat sensor is fine, had that checked. The only think the garage has said it could be is that the CAIS air intake system is leaking, or at fault somewhere, even though we can't see any leaks with a stationary car. Totally lost, at the moment.

[@mastersmods]

@@mrkirk4944 that's crazy mate. If the CAIS was leaking tho, wouldn't that have shown on the smoke test? Have you thought about taking it to a tuner like wayside or automodz?

[@mrkirk4944]

@@mastersmods Where I live nobody wants to touch it, even one or two tuners - their excuse is that with a modded car they could spend all day trying things but it could or could not be the mods themselves. They argue that because there is no history of the mod fitter, who fitted them, and what else has been done. I understand them, but I have asked if it's possible to draw up a check list then tick them all off from most important to less important. They argue that I will just be spending money, but never fixing the issue. I guess, what they're saying is that, IF they say YES - it's this, then when I spend money on it, and it doesn't work then I can hold them liable. I see their issue. I could spend £100 now, and get a cone-based Air Filter Intake Kit from ebay - this will then allow me to see if the CAIS is at fault. But £100, if it doesn't fix it, is a lot of cash to try something. Oh well. Thanks for the replies mate. Wish I had your skills, I am useless with cars.

[@mastersmods]

@@mrkirk4944 I do these vid to show people it's fairly easy really. It's just nuts and bolts. You don't have to spend big money, my air filter was 50 quid off ebay, you can get cheaper ones. Cars can be a head ache mate but sadly times like this it's about trial and error. Try one thing, if that doesn't work try the next

[@dok2304]

I wouldn’t touch that end of the sensor…