location of map sensor on astra

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Sun 6 Nov 2005 13:18
location of map sensor on astra - r3d_dwarf
Just found out how much a new map sensor costs for my astra 1600 gls its a m reg so instead i thought of getting a second hand one but where is it located? i know they are quite small about 4inches long and its plugged in somewhere but thats all i know.
(apparently its a common problem on these engines)
thanks
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Sun 6 Nov 2005 14:13
location of map sensor on astra - Ruperts Trooper
The engine mapping is on a chip inside the ECU. Vauxhall do move them around, depending on model and build date. Check a Haynes manual for your specific car. It may be behind the side trim in one of the front footwells.

The MAF (mass air flow) sensor is in the inlet tract between the air filter box and the throotle body.

How sure are you about what's actually faulty? Just because it's a common problem, relatively, doesn't mean that your car has the fault!

Your car will have a number of sensors, failure of any one of which can cause bad, or non-, running.
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Sun 6 Nov 2005 14:24
location of map sensor on astra - r3d_dwarf
well in pretty sure, sometimes at low rpm the ecu light flickers on the dash and it losses power but never cuts out or stalls but if i go faster its ok im just told that it sounds like the map sensor as its quite common fault.
mines the ecotec engine on a 1995 model M plate.

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Sun 6 Nov 2005 18:55
location of map sensor on astra - Ruperts Trooper
I've never heard of a map sensor. There's a MAF sensor and an ignition map.

Find an independent Vauxhall specialist and connect up to the Tech2 computer which will identify the fault in more detail.
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Sun 6 Nov 2005 19:10
location of map sensor on astra - Screwloose
r3d dwarf

You'll find your MAP [M-anifold A-bsolute P-ressure] sensor fixed to the bulkhead behind the engine. Follow it's thin rubber hose from the inlet manifold and it's the flat black block [stamped GM] with the rubber hose and a three-pin plug going to it.

Changing parts at random to find even a "common" engine-management fault requires exceptional luck; ("do you feel lucky...?")

Before spending anything, check that the throttle-plate housing is spotless inside and all the breather pipes, hoses and stubs are clear.
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Sun 6 Nov 2005 20:28
location of map sensor on astra - Number_Cruncher
I agree with everything Screwloose has said.

What is the fault on your car? Why do you think that a new MAP sensor is the answer?

I have replaced a few MAP sensors, but in most cases, it isn't the first place I'd look.

Number_Cruncher
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Sun 6 Nov 2005 23:48
location of map sensor on astra - Railroad.
The MAP sensor can be tested quite easily. There will be a three pin plug attached to it. The outer pins will be a 5V supply (with ignition on) and the other will be earth. The centre pin will be the signal to the ECU.

1. Check for voltage supply with ignition on, around 4.5V

2. Make sure earth connection is good. Earths should always be <5Ω. Make sure ignition is off when you check resistance, or you will not get an accurate reading.

3. Remove vacuum pipe, use voltmeter to probe centre pin with ignition on and gently apply vacuum to pipe. The voltage should fall down to about 0.5V, and return to around 4.5V when vacuum is released. If it does the the sensor is working and need not be replaced.

4. Check continuity of wiring from MAP sensor to ECU.
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