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[Mv6tipp]

hi every1 can any one tell me were my map sensor is on a 2.5td,and wot does it do thanks

[jonnycool]

I think you must mean the MAF sensor ( Mass Air Flow ), it measures how much air is flowing into the front of the engine so that a good fuel/air mix can be acheived

Jon

[aaronjb]

He could well mean MAP sensor Manifold Absolute Pressure.

Early TDs have MAP sensor and no MAF sensor (like mine), later models had both if memory serves.

It serves much the same function as the MAF sensor, although you need two sensors to do the job - MAP and air temperature (since air density can be calculated as a function of pressure & temperature, a MAF reads density directly).

Anyway, it's here, over on the passenger side inner wing on a '95:

[Mv6tipp]

thank you aaronjb that helped a lot,can u get this off your local vauxhall dealer or the great ebay

[aaronjb]

I don't see any on eBay unfortunately, so it looks like a trip to Vx for this unless any motor factors (like EuroCarParts or PartCo) can get one.

[Mv6tipp]

sound thanks for the info

[TheBoy]

Only U25DT (up to around 96) have a MAP. X25DT lose this sensor as they have a MAF.

[TheBoy]

Only U25DT (up to around 96) have a MAP. X25DT lose this sensor as they have a MAF.

Ignore that, I'm talking rubbish 

Its the air temp that the X25DT loses, not the MAP, which is used to judge turbo boost.

If its flagging MAP fault, these are mega reliable, check the turbo and its wastegate are working properly...

[Mv6tipp]

ok i will check this all out,my map sensor had no air tube on it i put one on but dont know were the other end goes too??

[aaronjb]

I've been there! That's why I had that pic handy

I don't know what age your car is, but assuming the vac routing is the same as mine (roughly)..

Take off the big black plastic cover on the inlet manifold (two plastic retainers at the front, one 8mm nut near the back).

You'll now see a pipe that runs front to back of the engine right under where that black cover was.  If you follow it, at the front it's quite narrow and connects to the vacuum pump, at the very rear it's wider and follow it round to the brake master cylinder.  In the middle of it's length, roughly, you'll see a 'thing' (one way valve) and in front of that a T-piece.

That T-piece should be connected to one side of the EGR solenoid - depending on year yours will either have two or three connections.  This fella on mine has two connections: http://i49.tinypic.com/a0waap.jpg

Now.. ignore all that pipework, it's not what you want (it's where the MAP was wrongly connected to on my car!) But I figured I should show you that so you know what bit to avoid, unlike the previous owner of my car...

Now.. the MAP sensor should be connected via a short length of vacuum hose to a nipple that is on the underside of the main runner of the inlet manifold.  You can find it best by feel - feel along the underside starting at the EGR valve end (this bit - http://i45.tinypic.com/9jonld.jpg - you should be feeling along the underside of the square aluminium section behind that).

About 1/3rd along you should find a small nipple with a vac hose connected to it - or you might need to attach a vac hose there.  Hook that up to the MAP sensor.  Look in this kind of area - http://i45.tinypic.com/2ymaet2.jpg - but ignore quite where my hose goes to because at this point in time it was plugged into the wrong thing.

If you can't find it let us know and I'll take more pictures (although not until Wednesday, as I'm off to Prague tomorrow at 6am!)

[Mv6tipp]

Hi all I connected the tube to the map sensor it works fine now for everything.I bought a tuning box for her but now when it goes to hit full boost it cuts out it keeps doing this so I have to disconnect it can any 1 help thanks every 1 ye have been great help