MAP Sensor & Purge Valve

25th March 2008, 20:00

So, went to the garage today and got the ECU read for a fault reading and it came up the Purge Valve and the MAP Sensor had given an error. So bought a Haynes manual and checked it out and it looks like the MAP sensor has been changed by the previous owner, only had the car a month. Could someone confirm this is the MAP sensor for me?

Also what are these two? Even with a Haynes it leaves me scratching my head a little.

The car is a 97 mk1 1.4i VSX with zero modifications.

25th March 2008, 20:05

in the second picture im sure the green plug is for the engine coolant temperature sensor . thats all i know

25th March 2008, 22:29

Looks like a very similar setup to the 106 GTI. Yes, that's the MAP sensor, as it's fixed into the inlet manifold. The other 2 sensors will be your coolant temperature sensors. One of them is just for the reading on your dash, and the other is the important one, it's the one that sends values back to the ECU on the temperature of your coolant. The one which appears to fit into the coolant housing will be the first one i've mentioned, and the important one (I think it's the blue one in your pic) will go into the side of the cylinder head.

25th March 2008, 23:07

Thanks guys, repped.

This kind of makes no sense though, why would the map sensor be giving a reading if it is quite new? One throey i was milling over at work was maybe a low voltage from the battery giving a false positive on the sensor? I took it out earlier and it seems fine and clean, could the purge valve be giving the error on the map sensor? What does that do?

27th March 2008, 14:54

is it possible to pull the map sensor out, and give it a clean?

27th March 2008, 15:14

Is it the correct MAP sensor? I bought a new MAP sensor once, and it looked identical to the OEM Pug one. The only difference was the last 2 digits of the part number... Anyway, when I tried to run the car with it, the ECU threw up an error, and the car ran like a bag of ...

27th March 2008, 22:00

dt_ i took it out and it as spotless, no grime on it at all. Could give it another wipe though.

Toad, haven't a clue tbh, must have been fitted by the previous owner. I will take the code down and give the local parts supplier a call and see if it matches to what they have. I know different map sensors are set for different pressures so i guess if i have the wrong one it could be that.

The car is really starting to do my head in, the cutting out went away for a few days and now it's back with a vengence. Very annoying, thought i'd go check how much a coil pack is in Halfords.. £120 they want! Walked out. I'm tempted just to take it into the garage but they said that all they have done in the past is changed the coil pack. Really is annoying

28th March 2008, 00:20

when mine went wrong it read out as a short circuit- replaced it and it solved it- cleaned it loads with no luck (was on and off working regardless of cleaning- sometimes thought it had helped then it would go bad)

29th March 2008, 09:13

Didn't the error already show there was an issue with the MAP sensor? Why are you looking at coilpacks?

29th March 2008, 11:23

I'm confused? Whats the actual problem? I see no mention of the car not running properly? I bet i've just missed it lol.

29th March 2008, 13:04

The car is cutting out when putting the clutch in, only happens when the car has warmed up, lol, maybe i should have mentioned that!

Took the map sensor out again today, it is SPOTLESS, seriously, and the hole it goes into is clean as a whistle too. Tried finding where you can buy purge valves but unable to find a place to buy them

29th March 2008, 13:18

The purge valve won't cause a problem.
The important temp sensor is the green one, that could cause your problem, £12 for a new one.

29th March 2008, 13:35

Quote:

Originally Posted by Toad

Didn't the error already show there was an issue with the MAP sensor? Why are you looking at coilpacks?

Yes mate, could replace it but surely a new one shouldn't go wrong too quickly?

I'm looking at Coil Packs as this has been mentioned as one of the things that could cause a problem with the revs dropping, it also misfires when driving along, will sort of jump and shake the car if you know what i mean?

Alex will try and source one and replace it.

29th March 2008, 14:35

Cutting out can only be caused by certain things.

Not enough Air - IAC Vavle problem
Not enough Fuel - Injector/ECU/Pump Fault/temp sensor
Not enough spark - Coil/Spark plug related

See what i mean? Process of elimination, check the cheap stuff first, IAC, plugs, temp sensor etc

29th March 2008, 16:29

Cheers RCD, will check the state of the IAC as it looks quie old, tried taking it off just now but can't remove the second screw to remove it. Repped.

30th March 2008, 12:55

There a git, if you take the whole throttle body off, its a lot easier

Thanks

Ross
RCD.

30th March 2008, 21:51

Yeah is a pain, will have a go on Wednesday. Local scrappy is never open, was gonna see if they had any saxo's sitting around but been up two weekends in a row now and never open!

Tried taking out the temp sensor to check the state of it and was sprayed by some pressured engine coolant... doh lol.

30th March 2008, 22:05

Whoops lol. Wait till the engines cool mate.